WO2025248690A1

WO2025248690A1 - Semiconductor optical integrated element

Info

Publication number: WO2025248690A1
Application number: PCT/JP2024/019816
Authority: WO
Inventors: 正和高林; 憲一阿部
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2024-05-30
Filing date: 2024-05-30
Publication date: 2025-12-04
Anticipated expiration: 2026-11-30

Abstract

A semiconductor optical integrated element (500, 600, 700, 750) according to the present disclosure comprises: a semiconductor laser unit (2) that is formed on a substrate (1) and that comprises a semiconductor laser; and an optical modulation unit (20) that is formed on the substrate (1) and that comprises a first optical modulation unit (5) having one end (5a) connected to one end (2a) of the semiconductor laser unit (2) via a first passive waveguide (3), and a second optical modulation unit (6) having one end (6a) connected to the other end (2b) of the semiconductor laser unit (2) via a second passive waveguide (4).

Description

semiconductor optical integrated device

　本開示は、半導体光集積素子に関する。 This disclosure relates to semiconductor optical integrated devices.

　スマートフォンに代表される移動体通信端末の普及、クラウドサービスの拡張によるデータサービスの多様化などにより、近年、通信トラフィックは急速に増大している。これにともない、さらなる光通信システムの高速化及び大容量化が要求されている。 Due to the widespread use of mobile communication devices such as smartphones and the diversification of data services due to the expansion of cloud services, communication traffic has been increasing rapidly in recent years. This has led to demand for even faster and larger capacity optical communication systems.

　マッハツェンダ（Ｍａｃｈ－Ｚｅｈｎｄｅｒ：ＭＺ）型半導体変調器（以下、ＭＺ型半導体光変調器と呼ぶ）は、従来から使用されているニオブ酸リチウム（Ｌｉｔｈｉｕｍ　Ｎｉｏｂａｔｅ：ＬｉＮｂＯ₃）などの誘電体材料からなるＬＮ導波路を利用したＬＮ光変調器と比較して、小型化、低消費電力化が可能であり、光通信システムの大容量化を図る上で重要なキーデバイスである。 Mach-Zehnder (MZ) type semiconductor modulators (hereinafter referred to as MZ type semiconductor optical modulators) can be made smaller and consume less power than conventional LN optical modulators that use LN waveguides made of dielectric materials such as lithium niobate (LiNbO ₃ ), and are therefore important key devices for increasing the capacity of optical communication systems.

　ＭＺ型半導体光変調器は、量子井戸構造が有する特有の量子閉じ込めシュタルク効果（Ｑｕａｎｔｕｍ　Ｃｏｎｆｉｎｅｄ　Ｓｔａｒｋ　Ｅｆｆｅｃｔ：ＱＣＳＥ）を利用するので、ＬＮ導波路と比較して電圧を印加した際の屈折率変化が大きいため、素子の小型化、低消費電力化が可能となる。 MZ-type semiconductor optical modulators utilize the Quantum Confined Stark Effect (QCSE), a characteristic of quantum well structures, which results in a larger change in refractive index when voltage is applied compared to LN waveguides, making it possible to miniaturize the device and reduce power consumption.

　また、半導体レーザとＭＺ型半導体光変調器とを集積した半導体光集積素子も開発されている。個々の素子をレンズなどを使用して結合させた構成と比較して、半導体光集積素子では小型化及び高出力化が可能となる。 Semiconductor optical integrated devices that integrate a semiconductor laser and an MZ-type semiconductor optical modulator have also been developed. Compared to configurations in which individual elements are combined using lenses or other devices, semiconductor optical integrated devices can be made smaller and produce higher output.

　しかしながら、半導体光集積素子として半導体レーザとＭＺ型半導体光変調器が直線状に並ぶような構成では、半導体レーザの長さが約５００μｍ、ＭＺ型半導体光変調器の長さが約４ｍｍであるため、半導体光集積素子の長手方向の長さが長くなるという問題があった。半導体光集積素子の長手方向の長さを短くするために、例えば特許文献１では、半導体レーザとＭＺ型半導体変調器を折り返した構成などが提案されている。 However, in a semiconductor optical integrated device where a semiconductor laser and an MZ-type semiconductor optical modulator are arranged in a straight line, the length of the semiconductor laser is approximately 500 μm and the length of the MZ-type semiconductor optical modulator is approximately 4 mm, which poses a problem of long longitudinal lengths of the semiconductor optical integrated device. To shorten the longitudinal length of the semiconductor optical integrated device, for example, Patent Document 1 proposes a configuration in which the semiconductor laser and MZ-type semiconductor modulator are folded back.

特開２０１２－７４４１１号公報JP 2012-74411 A

　しかしながら、特許文献１に記載の光半導体素子では、半導体レーザから出射したレーザ光を第１光結合器によって２つに分岐した上でＭＺ型半導体光変調器の第１位相変調部と第２位相変調部にそれぞれ出力する構成であるため、長手方向の素子の長さの短縮化が充分ではないという問題が依然としてあった。 However, in the optical semiconductor element described in Patent Document 1, the laser light emitted from the semiconductor laser is split into two by the first optical coupler and then output to the first phase modulation section and the second phase modulation section of the MZ-type semiconductor optical modulator, which means that the longitudinal length of the element cannot be sufficiently shortened.

　本開示は上記のような問題点を解決するためになされたものであり、半導体レーザとＭＺ型半導体光変調器とを集積した半導体光集積素子において、長手方向の長さがより短縮化された構成からなる半導体光集積素子を得ることを目的とする。 The present disclosure has been made to solve the above-mentioned problems, and aims to provide a semiconductor optical integrated device that integrates a semiconductor laser and an MZ-type semiconductor optical modulator and has a configuration that further shortens its longitudinal length.

　本開示に係る半導体光集積素子は、
　基板上に形成され、半導体レーザからなる半導体レーザ部と、
　前記基板上に形成され、前記半導体レーザ部の一端に第１受動型導波路を介して一端が接続された第１光変調部、及び前記半導体レーザ部の他端に第２受動型導波路を介して一端が接続された第２光変調部からなる光変調部と、を備える。 The semiconductor optical integrated device according to the present disclosure comprises:
a semiconductor laser portion formed on a substrate and made of a semiconductor laser;
The optical modulation unit is formed on the substrate and includes a first optical modulation unit having one end connected to one end of the semiconductor laser unit via a first passive waveguide, and a second optical modulation unit having one end connected to the other end of the semiconductor laser unit via a second passive waveguide.

　本開示に係る半導体光集積素子によれば、半導体レーザ部から出射するレーザ光を分岐することなく光変調部に出力する構成としたので、長手方向の長さがより短縮化された構成からなる半導体光集積素子を得ることができるという効果を奏する。 The semiconductor optical integrated element according to the present disclosure is configured so that the laser light emitted from the semiconductor laser section is output to the optical modulation section without being branched, thereby achieving the effect of obtaining a semiconductor optical integrated element with a configuration that further shortens its longitudinal length.

実施の形態１に係る半導体光集積素子の構成を示す上面図である。1 is a top view showing a configuration of a semiconductor optical integrated device according to a first embodiment; 実施の形態１に係る半導体光集積素子における半導体レーザ部の断面図である。1 is a cross-sectional view of a semiconductor laser portion in a semiconductor optical integrated device according to a first embodiment. 実施の形態１に係る半導体光集積素子における光変調部の断面図である。2 is a cross-sectional view of an optical modulation unit in the semiconductor optical integrated device according to the first embodiment. FIG. 実施の形態１に係る半導体光集積素子における受動型導波路の断面図である。1 is a cross-sectional view of a passive waveguide in a semiconductor optical integrated device according to a first embodiment. 実施の形態１の変形例に係る半導体光集積素子の構成を示す上面図である。FIG. 10 is a top view showing a configuration of a semiconductor optical integrated device according to a modification of the first embodiment. 実施の形態１に係る半導体光集積素子とＲＦ信号生成用ドライバ回路を組み合わせた構成を示す上面図である。1 is a top view showing a configuration in which a semiconductor optical integrated device according to a first embodiment is combined with a driver circuit for generating an RF signal; 実施の形態２に係る半導体光集積素子の構成を示す上面図である。FIG. 10 is a top view showing the configuration of a semiconductor optical integrated device according to a second embodiment. 実施の形態３に係る半導体光集積素子の構成を示す上面図である。FIG. 10 is a top view showing the configuration of a semiconductor optical integrated device according to a third embodiment. 実施の形態３の変形例に係る半導体光集積素子の構成を示す上面図である。FIG. 11 is a top view showing a configuration of a semiconductor optical integrated device according to a modification of the third embodiment. 実施の形態４に係る半導体光集積素子の構成を示す上面図である。FIG. 10 is a top view showing the configuration of a semiconductor optical integrated device according to a fourth embodiment. 実施の形態４に係る半導体光集積素子におけるモニタ用受光部の断面図である。FIG. 10 is a cross-sectional view of a monitor light-receiving portion in a semiconductor optical integrated device according to a fourth embodiment.

実施の形態１．
　図１は、実施の形態１に係る半導体光集積素子５００の構成を示す上面図である。 Embodiment 1.
FIG. 1 is a top view showing the configuration of a semiconductor optical integrated device 500 according to the first embodiment.

＜実施の形態１に係る半導体光集積素子の構成＞
　実施の形態１に係る半導体光集積素子５００は、半導体基板１上に設けられた、半導体レーザからなる半導体レーザ部２と、半導体レーザ部２の一端２ａに一端が接続された第１受動型導波路３と、半導体レーザ部２の他端２ｂに一端が接続された第２受動型導波路４と、第１受動型導波路３の他端に一端５ａが接続された第１光変調部５と、第２受動型導波路４の他端に一端６ａが接続された第２光変調部６と、第１光変調部５の他端５ｂに一端が接続された第３受動型導波路７と、第２光変調部６の他端６ｂに一端が接続された第４受動型導波路８と、第３受動型導波路７の他端及び第４受動型導波路８の他端に一端９ａが接続された光合波部９と、光合波部９の他端９ｂが接続された光出力部１０と、を備える。 <Configuration of semiconductor optical integrated device according to first embodiment>
The semiconductor optical integrated device 500 according to the first embodiment includes a semiconductor laser section 2 formed on a semiconductor substrate 1 and configured as a semiconductor laser, a first passive waveguide 3 having one end connected to one end 2a of the semiconductor laser section 2, a second passive waveguide 4 having one end connected to the other end 2b of the semiconductor laser section 2, a first optical modulation section 5 having one end 5a connected to the other end of the first passive waveguide 3, and a second passive waveguide 5. a second optical modulation section 6 having one end 6a connected to the other end of the first passive waveguide 4; a third passive waveguide 7 having one end connected to the other end 5b of the first optical modulation section 5; a fourth passive waveguide 8 having one end connected to the other end 6b of the second optical modulation section 6; an optical multiplexing section 9 having one end 9a connected to the other end of the third passive waveguide 7 and the other end of the fourth passive waveguide 8; and an optical output section 10 having the other end 9b of the optical multiplexing section 9 connected.

　光変調部２０は、第１光変調部５と第２光変調部６のペアで構成される。半導体レーザ部２は、光変調部２０と対向する位置に配置される。半導体レーザ部２の長手方向と、第１光変調部５及び第２光変調部６の長手方向は互いに平行な位置関係にある。第１受動型導波路３から第４受動型導波路８までを総称して受動型導波路３０と呼ぶ。なお、半導体基板１以外の基板を用いてもよい。 The optical modulation section 20 is composed of a pair of a first optical modulation section 5 and a second optical modulation section 6. The semiconductor laser section 2 is positioned opposite the optical modulation section 20. The longitudinal direction of the semiconductor laser section 2 and the longitudinal directions of the first optical modulation section 5 and second optical modulation section 6 are parallel to each other. The first passive waveguide 3 to the fourth passive waveguide 8 are collectively referred to as the passive waveguides 30. Note that substrates other than the semiconductor substrate 1 may also be used.

　半導体光集積素子５００を構成する、半導体レーザ部２、光変調部２０、及び受動型導波路３０の各構造及び製造方法について、以下に説明する。 The structures and manufacturing methods of the semiconductor laser section 2, optical modulation section 20, and passive waveguide 30 that make up the semiconductor optical integrated device 500 are described below.

＜半導体レーザ部の構造＞
　半導体レーザ部２について、光の伝搬方向に直交する面における断面図を表す図２を用いて説明する。半導体レーザ部２は、半導体基板１上に形成されたｎ型下部クラッド層４１の一部と、利得コア層４２と、ｐ型上部クラッド層４３の一部がストライプ状に形成されたハイメサ型構造５５と、ストライプ状のハイメサ型構造５５の両側面のｎ型下部クラッド層４１上に形成されたｐ型電流ブロック層４５ａ及びｎ型電流ブロック層４５ｂからなる電流ブロック層４５と、ハイメサ型構造５５及び電流ブロック層４５の上面に形成されたｐ型上部クラッド層４３の残部及びｐ型コンタクト層４６と、ｐ型コンタクト層４６の上面に形成されたレーザ部電極４７と、少なくともハイメサ型構造５５の側面部及びレーザ部電極４７に覆われていないｐ型コンタクト層４６の表面を覆う保護絶縁膜４８と、ハイメサ型構造５５から離間してｎ型下部クラッド層４１上に形成されたｎ型コンタクト層４９と、ｎ型コンタクト層４９上に設けられた下側電極５０と、で構成されている。 <Structure of semiconductor laser part>
The semiconductor laser section 2 will be described with reference to FIG. 2, which shows a cross-sectional view taken along a plane perpendicular to the light propagation direction. the semiconductor laser section 2 is composed of: a part of the n-type lower cladding layer 41 formed on the semiconductor substrate 1; a gain core layer 42; a high mesa structure 55 in which a part of the p-type upper cladding layer 43 is formed in a stripe shape; a current blocking layer 45 consisting of a p-type current blocking layer 45 a and an n-type current blocking layer 45 b formed on the n-type lower cladding layer 41 on both sides of the stripe-shaped high mesa structure 55; a remaining part of the p-type upper cladding layer 43 and a p-type contact layer 46 formed on the upper surfaces of the high mesa structure 55 and the current blocking layer 45; a laser section electrode 47 formed on the upper surface of the p-type contact layer 46; a protective insulating film 48 covering at least the side portions of the high mesa structure 55 and the surface of the p-type contact layer 46 that is not covered by the laser section electrode 47; an n-type contact layer 49 formed on the n-type lower cladding layer 41 at a distance from the high mesa structure 55; and a lower electrode 50 provided on the n-type contact layer 49.

　利得コア層４２は、光を増幅する機能を持つ半導体層である。n型下部クラッド層４１及びp型上部クラッド層４３は、利得コア層４２に光を閉じ込めるため、利得コア層４２よりも低い屈折率の半導体層で構成されている。 The gain core layer 42 is a semiconductor layer that has the function of amplifying light. The n-type lower cladding layer 41 and the p-type upper cladding layer 43 are composed of semiconductor layers with a lower refractive index than the gain core layer 42 in order to confine light in the gain core layer 42.

　ｐ型コンタクト層４６は、レーザ部電極４７から半導体層へ電流を注入する際の抵抗を小さくするため、ｐ型上部クラッド層４３よりも低抵抗である半導体層で構成されている。 The p-type contact layer 46 is composed of a semiconductor layer with lower resistance than the p-type upper cladding layer 43 in order to reduce the resistance when current is injected from the laser portion electrode 47 into the semiconductor layer.

　電流ブロック層４５は、電流を流さない構造及び材料で構成され、利得コア層４２に電流を集中させるための半導体層として機能する。図２に示す半導体レーザ部２の一例では、ｐ型電流ブロック層４５ａ及びｐ型電流ブロック層４５ａの内部に形成され端部が利得コア層４２と接していないｎ型電流ブロック層４５ｂの２層で構成されている。 The current blocking layer 45 is constructed with a structure and material that does not allow current to flow, and functions as a semiconductor layer for concentrating current in the gain core layer 42. In the example of the semiconductor laser section 2 shown in Figure 2, it is composed of two layers: a p-type current blocking layer 45a and an n-type current blocking layer 45b formed inside the p-type current blocking layer 45a, the ends of which do not contact the gain core layer 42.

　保護絶縁膜４８は、酸化膜または窒化膜などの無機絶縁膜、あるいはベンゾシクロブテン（Ｂｅｎｚｏｃｙｃｌｏｂｕｔｅｎｅ：ＢＣＢ）などの有機絶縁膜からなる絶縁性材料で構成される。保護絶縁膜４８は、雰囲気中の酸素、水などにより半導体が酸化すること、あるいは変質することを防止する機能を有する。 The protective insulating film 48 is made of an insulating material, such as an inorganic insulating film such as an oxide film or a nitride film, or an organic insulating film such as benzocyclobutene (BCB). The protective insulating film 48 functions to prevent the semiconductor from being oxidized or altered by oxygen, water, etc. in the atmosphere.

　実施の形態１で示す半導体レーザ部２は、利得コア層４２の側壁、つまりハイメサ型構造５５の側面部に電流ブロック層４５を形成した埋め込み型構造である。埋め込み型構造では、利得コア層４２で発生する発熱が電流ブロック層４５を介して拡散され、利得コア層４２の温度上昇に起因する利得減少を抑制できるため、高出力化が可能となる。 The semiconductor laser section 2 shown in embodiment 1 has a buried structure in which a current blocking layer 45 is formed on the sidewall of the gain core layer 42, i.e., on the side surface of the high mesa structure 55. In a buried structure, heat generated in the gain core layer 42 is diffused via the current blocking layer 45, suppressing gain reduction due to temperature rise in the gain core layer 42, thereby enabling high output power.

＜半導体レーザ部の製造方法＞
　半導体レーザ部２の製造方法について、以下に説明する。例えば半導体結晶の面方位の（１００）面を基板面とするＩｎＰ基板からなる半導体基板１の上に、有機金属気相成長法（Ｍｅｔａｌ　Ｏｒｇａｎｉｃ　Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ：ＭＯＣＶＤ）を用いて、ｎ型下部クラッド層４１を構成する層厚２０００ｎｍのｎ型ＩｎＰ層と、半導体レーザ部２の利得コア層４２として層厚の合計が１００ｎｍであるＡｌＧａＩｎＡｓからなる多重量子井戸層と、ｐ型上部クラッド層４３を構成する層厚２０００ｎｍのｐ型ＩｎＰ層とを、順次エピタキシャル結晶成長する。 <Method of manufacturing semiconductor laser part>
The following describes a method for manufacturing the semiconductor laser portion 2. For example, on the semiconductor substrate 1 made of an InP substrate having a (100) plane of semiconductor crystal orientation as the substrate surface, an n-type InP layer having a thickness of 2000 nm that constitutes the n-type lower cladding layer 41, a multi-quantum well layer made of AlGaInAs with a total thickness of 100 nm that serves as the gain core layer 42 of the semiconductor laser portion 2, and a p-type InP layer having a thickness of 2000 nm that constitutes the p-type upper cladding layer 43 are epitaxially grown in this order using metal organic chemical vapor deposition (MOCVD).

　利得コア層４２を構成する多重量子井戸層は、発光に寄与する井戸層と、井戸層よりもバンドギャップの大きいバリア層とのペアの繰り返しで構成される。利得コア層４２は、例えば８ペアの多重量子井戸層で構成される。なお、上述のエピタキシャル結晶成長で形成したｎ型下部クラッド層４１は、後述の光変調部２０及び受動型導波路３０のｎ型下部クラッド層と共通化することが可能である。 The multiple quantum well layers that make up the gain core layer 42 are composed of repeated pairs of well layers that contribute to light emission and barrier layers with a larger band gap than the well layers. The gain core layer 42 is composed of, for example, eight pairs of multiple quantum well layers. The n-type lower cladding layer 41 formed by the above-mentioned epitaxial crystal growth can be shared with the n-type lower cladding layer of the optical modulation section 20 and passive waveguide 30, which will be described later.

＜光変調部の構造＞
　光変調部２０について、光の伝搬方向に直交する面における断面図を表す図３を用いて説明する。 <Structure of the optical modulation section>
The optical modulation section 20 will be described with reference to FIG. 3, which shows a cross-sectional view taken along a plane perpendicular to the propagation direction of light.

　光変調部２０は、半導体基板１上に形成されたｎ型下部クラッド層６１の一部と、光変調コア層６２と、ｐ型上部クラッド層６３と、ｐ型コンタクト層６４がストライプ状に形成されたハイメサ型構造６５と、ｐ型コンタクト層６４の上面に形成された光変調部電極６７と、少なくともハイメサ型構造６５の側面部を覆う保護絶縁膜６８と、ハイメサ型構造６５から離間してｎ型下部クラッド層６１上に形成されたｎ型コンタクト層６９と、ｎ型コンタクト層６９上に設けられた下側電極７０と、で構成されている。 The optical modulation section 20 is composed of a portion of an n-type lower cladding layer 61 formed on the semiconductor substrate 1, an optical modulation core layer 62, a p-type upper cladding layer 63, a high mesa structure 65 in which a p-type contact layer 64 is formed in a striped pattern, an optical modulation section electrode 67 formed on the upper surface of the p-type contact layer 64, a protective insulating film 68 covering at least the side surface of the high mesa structure 65, an n-type contact layer 69 formed on the n-type lower cladding layer 61 and spaced apart from the high mesa structure 65, and a lower electrode 70 provided on the n-type contact layer 69.

　光変調コア層６２は、逆バイアスを印加した際に屈折率が変わることで伝搬する光の位相を変化させる機能を持つ半導体層である。ｐ型上部クラッド層６３は、光変調コア層６２に光を閉じ込めるため、光変調コア層６２よりも低い屈折率の半導体層で構成されている。 The optical modulation core layer 62 is a semiconductor layer that has the function of changing the phase of propagating light by changing the refractive index when a reverse bias is applied. The p-type upper cladding layer 63 is composed of a semiconductor layer with a lower refractive index than the optical modulation core layer 62 in order to confine light in the optical modulation core layer 62.

　ｐ型コンタクト層６４は、光変調部電極６７から半導体層に電圧を印加する際の抵抗を小さくするため、ｐ型上部クラッド層６３よりも低抵抗である半導体層で構成されている。 The p-type contact layer 64 is composed of a semiconductor layer with lower resistance than the p-type upper cladding layer 63 in order to reduce the resistance when voltage is applied to the semiconductor layer from the optical modulation section electrode 67.

　保護絶縁膜６８は、酸化膜または窒化膜などの無機絶縁膜、あるいはＢＣＢなどの有機絶縁膜からなる絶縁性材料で構成される。保護絶縁膜６８は、雰囲気中の酸素、水などにより半導体が酸化すること、あるいは変質することを防止する機能を有する。 The protective insulating film 68 is made of an insulating material, such as an inorganic insulating film such as an oxide film or a nitride film, or an organic insulating film such as BCB. The protective insulating film 68 functions to prevent the semiconductor from being oxidized or altered by oxygen, water, etc. in the atmosphere.

　実施の形態１で示す光変調部２０は、ｐ型コンタクト層６４からｎ型下部クラッド層６１の一部までをＲＩＥ法などでエッチングしたハイメサ型構造６５で構成されている。 The optical modulation section 20 shown in embodiment 1 is configured with a high mesa structure 65 in which the p-type contact layer 64 to a portion of the n-type lower cladding layer 61 is etched using a method such as RIE.

　ハイメサ型構造６５では、光変調コア層６２とエッチングされた領域との屈折率差が大きいため、光変調コア層６２に光を強く閉じ込めることができる。ハイメサ型構造６５によって、光変調コア層６２の屈折率が変化した際に、光の位相変化量が大きくなるため、高い変調効率が得られる。 In the high mesa structure 65, the difference in refractive index between the optical modulation core layer 62 and the etched region is large, allowing light to be tightly confined within the optical modulation core layer 62. The high mesa structure 65 increases the amount of phase change in light when the refractive index of the optical modulation core layer 62 changes, resulting in high modulation efficiency.

＜光変調部の製造方法＞
　光変調部２０の製造方法について、以下に説明する。エピタキシャル結晶成長したｎ型下部クラッド層６１の表面に、光変調コア層６２を構成する層厚の合計が３００ｎｍであるＡｌＧａＩｎＡｓからなる多重量子井戸層と、ｐ型上部クラッド層６３を構成する層厚２０００ｎｍのｐ型ＩｎＰ層と、ｐ型コンタクト層６４を構成する層厚３００ｎｍのｐ型ＩｎＧａＡｓ層とを、順次エピタキシャル結晶成長する。 <Method of manufacturing the optical modulation section>
The manufacturing method of the optical modulation section 20 is described below. On the surface of the epitaxially grown n-type lower cladding layer 61, a multi-quantum well layer made of AlGaInAs with a total layer thickness of 300 nm that constitutes the optical modulation core layer 62, a p-type InP layer with a layer thickness of 2000 nm that constitutes the p-type upper cladding layer 63, and a p-type InGaAs layer with a layer thickness of 300 nm that constitutes the p-type contact layer 64 are sequentially grown by epitaxial crystal growth.

　エピタキシャル結晶成長後、各半導体層をＲＩＥ法などにより選択的にエッチングして、ハイメサ型構造６５を形成する。ｐ型コンタクト層６４上に、Ｔｉ、Ａｕ、Ｐｔ、Ｎｂ、Ｎｉなどの金属で構成された光変調部電極６７と、半導体表面を保護するための保護絶縁膜６８を構成する膜厚３００ｎｍのＳｉＯ₂膜を、ＣＶＤ法などの成膜方法により形成する。 After the epitaxial crystal growth, each semiconductor layer is selectively etched by RIE or the like to form a high mesa structure 65. On the p-type contact layer 64, an optical modulation section electrode 67 made of a metal such as Ti, Au, Pt, Nb, or Ni, and a 300 nm thick _SiO2 film constituting a protective insulating film 68 for protecting the semiconductor surface are formed by a film formation method such as CVD.

＜受動型導波路の機能＞
　受動型導波路３０は、半導体基板１上に形成した各素子部を接続させるための導波路として機能する。 <Functions of passive waveguides>
The passive waveguide 30 functions as a waveguide for connecting each element portion formed on the semiconductor substrate 1 .

＜受動型導波路の構造＞
　受動型導波路３０について、光の伝搬方向に直交する面における断面図を表す図４を用いて説明する。受動型導波路３０は、半導体基板１上に形成されたｎ型下部クラッド層８１の一部と、導波路コア層８２と、ｉ型上部クラッド層８３とがストライプ状に形成されたハイメサ型構造８５と、ハイメサ型構造８５の上面及び側面部を少なくとも覆う保護絶縁膜８８と、で構成されている。 <Structure of passive waveguide>
4, which shows a cross-sectional view of the passive waveguide 30 taken along a plane perpendicular to the light propagation direction. The passive waveguide 30 is composed of a high mesa structure 85 in which a part of an n-type lower cladding layer 81, a waveguide core layer 82, and an i-type upper cladding layer 83 are formed on a semiconductor substrate 1 in a striped pattern, and a protective insulating film 88 that covers at least the top and side surfaces of the high mesa structure 85.

　実施の形態１に係る半導体光集積素子５００における受動型導波路３０は、ｉ型上部クラッド層８３からｎ型下部クラッド層８１の一部までをＲＩＥ法などでエッチングすることにより形成されたハイメサ型構造８５で構成される。半導体レーザ部２と光変調部２０とを接続するため、これらを接続する受動型導波路３０は湾曲した領域（以下、湾曲部分と呼ぶ）を一部に設ける必要がある。受動型導波路３０において、湾曲部分での光学的損失を抑制するため、受動型導波路３０は導波路コア層８２内に光を強く閉じ込めることが可能なハイメサ型構造８５を適用することが好適である。 The passive waveguide 30 in the semiconductor optical integrated device 500 according to the first embodiment has a high mesa structure 85 formed by etching the i-type upper cladding layer 83 through a portion of the n-type lower cladding layer 81 using a method such as RIE. To connect the semiconductor laser section 2 and the optical modulation section 20, the passive waveguide 30 connecting them must have a curved region (hereinafter referred to as the curved portion) in part. To suppress optical loss in the curved portion of the passive waveguide 30, it is preferable for the passive waveguide 30 to have a high mesa structure 85 that can tightly confine light within the waveguide core layer 82.

　ｉ型上部クラッド層８３は、導波路コア層８２に光を閉じ込めるため、導波路コア層８２よりも低い屈折率の半導体層で構成されている。 The i-type upper cladding layer 83 is composed of a semiconductor layer with a lower refractive index than the waveguide core layer 82 in order to confine light in the waveguide core layer 82.

　保護絶縁膜８８は、酸化膜または窒化膜などの無機絶縁膜、あるいはＢＣＢなどの有機絶縁膜からなる絶縁性材料で構成される。保護絶縁膜８８は、雰囲気中の酸素、水などにより半導体が酸化すること、あるいは変質することを防止する機能を有する。 The protective insulating film 88 is made of an insulating material, such as an inorganic insulating film such as an oxide film or a nitride film, or an organic insulating film such as BCB. The protective insulating film 88 functions to prevent the semiconductor from being oxidized or altered by oxygen, water, etc. in the atmosphere.

　導波路コア層８２は、光変調部２０の光変調コア層６２と同じ構造であってもよい。そうすることで、半導体レーザ部２の利得コア層４２と、光変調部２０及び受動型導波路３０の光変調コア層６２の２種類のコア層で半導体光集積素子５００を構成できる。 The waveguide core layer 82 may have the same structure as the optical modulation core layer 62 of the optical modulation section 20. In this way, the semiconductor optical integrated device 500 can be constructed with two types of core layers: the gain core layer 42 of the semiconductor laser section 2 and the optical modulation core layer 62 of the optical modulation section 20 and passive waveguide 30.

　受動型導波路３０は、光の強度及び位相を変化させる機能を有しないため、電極、コンタクト層などに必要な電流または電圧を印加するための構造は必要ない。 Because the passive waveguide 30 does not have the function of changing the intensity or phase of light, it does not require structures for applying the necessary current or voltage to electrodes, contact layers, etc.

＜受動型導波路の製造方法＞
　受動型導波路３０の製造方法について、以下に説明する。半導体レーザ部２の形成時にエピタキシャル結晶成長したｎ型下部クラッド層８１の表面に、導波路コア層８２を構成する層厚の合計が３００ｎｍであるＡｌＧａＩｎＡｓからなる多重量子井戸層と、ｉ型上部クラッド層８３を構成する層厚２０００ｎｍのｉ型ＩｎＰ層とを、順次エピタキシャル結晶成長する。 <Method for manufacturing a passive waveguide>
The following describes a method for manufacturing the passive waveguide 30. On the surface of the n-type lower cladding layer 81 epitaxially grown during the formation of the semiconductor laser portion 2, a multi-quantum well layer made of AlGaInAs and having a total thickness of 300 nm constituting the waveguide core layer 82, and an i-type InP layer having a thickness of 2000 nm constituting the i-type upper cladding layer 83 are sequentially grown by epitaxial crystal growth.

　エピタキシャル結晶成長後、各半導体層をＲＩＥ法などで選択的にエッチングして、ハイメサ型構造８５を形成する。半導体表面を保護するための保護絶縁膜８８を構成する膜厚３００ｎｍのＳｉＯ₂膜を、ＣＶＤ法などの成膜方法により形成する。 After the epitaxial crystal growth, each semiconductor layer is selectively etched by RIE or the like to form a high mesa structure 85. A 300 nm thick _SiO2 film that constitutes a protective insulating film 88 for protecting the semiconductor surface is formed by a film formation method such as CVD.

＜実施の形態１に係る半導体光集積素子の動作＞
　実施の形態１に係る半導体光集積素子５００の動作を以下に説明する。半導体レーザ部２の一端２ａから出射されるレーザ光は、第１受動型導波路３内を伝搬し、第１光変調部５の一端５ａから第１光変調部５の内部に入射する。第１光変調部５では、光変調部電極６７にＲＦ電気信号が印加され、導波路の屈折率が変化することにより、第１光変調部５を透過する光の位相が変化する。 <Operation of the semiconductor optical integrated device according to the first embodiment>
The operation of the semiconductor optical integrated device 500 according to the first embodiment will be described below. Laser light emitted from one end 2a of the semiconductor laser unit 2 propagates through the first passive waveguide 3 and enters the first optical modulation unit 5 from one end 5a of the first optical modulation unit 5. In the first optical modulation unit 5, an RF electrical signal is applied to the optical modulation unit electrode 67, which changes the refractive index of the waveguide, thereby changing the phase of the light passing through the first optical modulation unit 5.

　一方、半導体レーザ部２の他端２ｂから出射されるレーザ光は、第２受動型導波路４内を伝搬し、第２光変調部６の一端６ａから第２光変調部６の内部に入射する。第２光変調部６では、光変調部電極６７にＲＦ電気信号が印加され、導波路の屈折率が変化することにより、第２光変調部６を透過する光の位相が変化する。 Meanwhile, the laser light emitted from the other end 2b of the semiconductor laser unit 2 propagates through the second passive waveguide 4 and enters the second optical modulation unit 6 from one end 6a of the second optical modulation unit 6. In the second optical modulation unit 6, an RF electrical signal is applied to the optical modulation unit electrode 67, changing the refractive index of the waveguide and thereby changing the phase of the light passing through the second optical modulation unit 6.

　光変調部２０の第１光変調部５及び第２光変調部６においてそれぞれ位相変調された光は、第３受動型導波路７及び第４受動型導波路８をそれぞれ介して光合波部９に入射して一つの強度変調信号に合波されて、光出力部１０から半導体光集積素子５００の外部に出射される。 The light phase-modulated in the first optical modulation section 5 and second optical modulation section 6 of the optical modulation section 20 enters the optical multiplexing section 9 via the third passive waveguide 7 and fourth passive waveguide 8, respectively, where it is multiplexed into a single intensity-modulated signal and emitted from the optical output section 10 to the outside of the semiconductor optical integrated device 500.

＜実施の形態１に係る半導体光集積素子の機能＞
　半導体レーザ部２の両端から出力されたレーザ光は受動型導波路３０を伝搬して、第１光変調部５及び第２光変調部６にそれぞれ入力され、光合波部９により合波されて出力される。 <Functions of the semiconductor optical integrated device according to the first embodiment>
The laser light output from both ends of the semiconductor laser section 2 propagates through the passive waveguide 30, is input to the first optical modulation section 5 and the second optical modulation section 6, respectively, and is then multiplexed by the optical multiplexing section 9 and output.

　光変調部２０では光変調部電極６７にＲＦ電気信号が印加され、導波路の屈折率が変化して、導波路を透過する光の位相が変化することで、光合波部９により合波される光出力強度が変化し、強度変調信号が生成される。 In the optical modulation unit 20, an RF electrical signal is applied to the optical modulation unit electrode 67, which changes the refractive index of the waveguide and the phase of the light passing through the waveguide. This changes the intensity of the optical output combined by the optical combiner 9, generating an intensity-modulated signal.

　例えば第１光変調部５及び第２光変調部６の光変調部電極６７に同一の大きさの数Ｖ程度の逆バイアス電圧を印加した上で、第１光変調部５及び第２光変調部６のそれぞれに逆向きの電圧（ｐｕｓｈ－ｐｕｌｌ）が印加されるようなＲＦ電気信号を印加することで、強度変調信号を生成できる。 For example, an intensity-modulated signal can be generated by applying the same reverse bias voltage of several volts to the optical modulation section electrodes 67 of the first optical modulation section 5 and the second optical modulation section 6, and then applying an RF electrical signal that applies reverse voltages (push-pull) to each of the first optical modulation section 5 and the second optical modulation section 6.

＜実施の形態１に係る半導体光集積素子の特徴＞
　特許文献１に記載の光半導体素子では、半導体レーザ部から出力されるレーザ光を分岐部により分岐して、各レーザ光を各変調部にそれぞれ入力している。一方、実施の形態１に係る半導体光集積素子は、半導体レーザ部２の両端からそれぞれ出力された２つのレーザ光を光変調部２０に直接入力している点に特徴がある。 <Features of the semiconductor optical integrated device according to the first embodiment>
In the optical semiconductor device described in Patent Document 1, the laser light output from the semiconductor laser unit is branched by a branching unit, and each laser light is input to each modulation unit. On the other hand, the semiconductor optical integrated device according to the first embodiment is characterized in that two laser lights output from both ends of the semiconductor laser unit 2 are directly input to the optical modulation unit 20.

＜実施の形態１に係る半導体光集積素子の効果＞
　実施の形態１に係る半導体光集積素子によると、半導体レーザ部から光変調部にレーザ光を出力する場合に、受動型導波路中に分岐部を設ける必要がないため、チップ長の短尺化が図られ、また、受動型導波路中に分岐部が無いため分岐部に起因する損失が発生しないので、光出力が増大した半導体光集積素子が得られるという効果を奏する。 <Effects of the semiconductor optical integrated device according to the first embodiment>
According to the semiconductor optical integrated device of the first embodiment, when laser light is output from the semiconductor laser section to the optical modulation section, there is no need to provide a branch section in the passive waveguide, which makes it possible to shorten the chip length. Furthermore, since there is no branch section in the passive waveguide, no loss due to the branch section occurs, which has the effect of providing a semiconductor optical integrated device with increased optical output.

実施の形態１の変形例．
＜実施の形態１の変形例に係る半導体光集積素子の特徴＞
　図５は、実施の形態１の変形例に係る半導体光集積素子５５０の構成を示す上面図である。図１に示す実施の形態１に係る半導体光集積素子５００は、１つの半導体レーザ部２から出力されるレーザ光を用いていた。一方、実施の形態１の変形例に係る半導体光集積素子５５０では、第１半導体レーザからなる第１半導体レーザ部２２及び第２半導体レーザからなる第２半導体レーザ部２３の２つの半導体レーザ部で構成されている点に特徴がある。 A modified example of embodiment 1.
<Features of the semiconductor optical integrated device according to the modification of the first embodiment>
5 is a top view showing the configuration of a semiconductor optical integrated device 550 according to a modification of the first embodiment. The semiconductor optical integrated device 500 according to the first embodiment shown in FIG. 1 uses laser light output from one semiconductor laser unit 2. On the other hand, the semiconductor optical integrated device 550 according to the modification of the first embodiment is characterized in that it is configured with two semiconductor laser units, namely, a first semiconductor laser unit 22 consisting of a first semiconductor laser and a second semiconductor laser unit 23 consisting of a second semiconductor laser.

　第１半導体レーザ部２２は第１光変調部５に対向する位置において、第１光変調部５に平行に配置される。第２半導体レーザ部２３は第２光変調部６に対向する位置において、第２光変調部６に平行に配置される。 The first semiconductor laser unit 22 is positioned opposite the first optical modulation unit 5 and is arranged parallel to the first optical modulation unit 5. The second semiconductor laser unit 23 is positioned opposite the second optical modulation unit 6 and is arranged parallel to the second optical modulation unit 6.

＜実施の形態１の変形例に係る半導体光集積素子の構成＞
　実施の形態１の変形例に係る半導体光集積素子５５０は、半導体基板１上に設けられた、第１半導体レーザからなる第１半導体レーザ部２２と、第２半導体レーザからなる第２半導体レーザ部２３と、第１半導体レーザ部２２の一端２２ａに一端が接続された第１受動型導波路３と、第２半導体レーザ部２３の一端２３ａに一端が接続された第２受動型導波路４と、第１受動型導波路３の他端に一端５ａが接続された第１光変調部５と、第２受動型導波路４の他端に一端６ａが接続された第２光変調部６と、第１光変調部５の他端５ｂに一端が接続された第３受動型導波路７と、第２光変調部６の他端６ｂに一端が接続された第４受動型導波路８と、第３受動型導波路７の他端及び第４受動型導波路８の他端に一端９ａが接続された光合波部９と、光合波部９の他端９ｂに接続された光出力部１０と、を備える。 <Configuration of Semiconductor Optical Integrated Device According to Modification of First Embodiment>
The semiconductor optical integrated device 550 according to the modification of the first embodiment includes a first semiconductor laser portion 22 formed on a semiconductor substrate 1 and consisting of a first semiconductor laser, a second semiconductor laser portion 23 formed on a second semiconductor laser, a first passive waveguide 3 having one end connected to one end 22a of the first semiconductor laser portion 22, a second passive waveguide 4 having one end connected to one end 23a of the second semiconductor laser portion 23, and a second passive waveguide 5 having one end 5a connected to the other end of the first passive waveguide 3. the second optical modulation section 6 having one end 6a connected to the other end of the second passive waveguide 4; a third passive waveguide 7 having one end connected to the other end 5b of the first optical modulation section 5; a fourth passive waveguide 8 having one end connected to the other end 6b of the second optical modulation section 6; an optical multiplexing section 9 having one end 9a connected to the other end of the third passive waveguide 7 and the other end of the fourth passive waveguide 8; and an optical output section 10 connected to the other end 9b of the optical multiplexing section 9.

　第１半導体レーザ部２２及び第２半導体レーザ部２３の断面構造は、実施の形態１の半導体レーザ部２の断面構造と同一であるので、説明を省略する。 The cross-sectional structures of the first semiconductor laser section 22 and the second semiconductor laser section 23 are the same as the cross-sectional structure of the semiconductor laser section 2 in embodiment 1, so a description thereof will be omitted.

＜実施の形態１の変形例に係る半導体光集積素子の効果＞
　以上、実施の形態１の変形例に係る半導体光集積素子によると、上述のように第１半導体レーザ部及び第２半導体レーザ部の２つの半導体レーザ部が、光変調部を構成する第１光変調部及び第２光変調部にそれぞれ対向する位置において平行に配置されるため、実施の形態１と同様、半導体レーザ部から光変調部にレーザ光を出力する場合に、受動型導波路中に分岐部を設ける必要がないため、チップ長の短尺化が図られ、また、受動型導波路中に分岐部が無いため分岐部に起因する損失が発生しないので、光出力が増大した半導体光集積素子が得られるという効果を奏する。 <Effects of the semiconductor optical integrated device according to the modification of the first embodiment>
As described above, according to the semiconductor optical integrated element of the modification of the first embodiment, as described above, the two semiconductor laser portions, the first semiconductor laser portion and the second semiconductor laser portion, are arranged in parallel at positions facing the first optical modulation portion and the second optical modulation portion that constitute the optical modulation portion, respectively. Therefore, similar to the first embodiment, when outputting laser light from the semiconductor laser portion to the optical modulation portion, there is no need to provide a branch portion in the passive waveguide, which enables the chip length to be shortened. Furthermore, since there is no branch portion in the passive waveguide, no loss due to the branch portion occurs, and therefore, an effect is achieved in which a semiconductor optical integrated element with increased optical output is obtained.

＜実施の形態１に係る半導体光集積素子とドライバ回路との組み合わせ＞
　実施の形態１に係る半導体光集積素子５００を駆動する際には、図６に示すように、ＲＦ信号生成用のドライバ回路９０と組み合わせて使用する。 <Combination of the semiconductor optical integrated device according to the first embodiment and the driver circuit>
When driving the semiconductor optical integrated device 500 according to the first embodiment, it is used in combination with a driver circuit 90 for generating an RF signal, as shown in FIG.

　ＲＦ信号生成用のドライバ回路９０にはＲＦ信号出力用の電極パッド９１が配置され、ワイヤ９２などにより半導体光集積素子５００に形成されたＲＦ信号入力用配線部９３と接続し、光変調部２０にＲＦ信号を印加する。光変調部２０を伝搬するＲＦ信号は、伝搬中にある程度減衰して、光変調部２０の終端まで到達する。光変調部２０の終端に、光変調部２０のインピーダンスに一致した抵抗値を有する終端抵抗９４を配置することにより、ＲＦ信号の終端部での不要な反射を抑制できる。 An electrode pad 91 for RF signal output is arranged on the driver circuit 90 for generating the RF signal, and is connected by a wire 92 or the like to an RF signal input wiring section 93 formed on the semiconductor optical integrated device 500, and an RF signal is applied to the optical modulation section 20. The RF signal propagating through the optical modulation section 20 is attenuated to some extent during propagation before reaching the end of the optical modulation section 20. By placing a termination resistor 94 at the end of the optical modulation section 20, with a resistance value that matches the impedance of the optical modulation section 20, unwanted reflection at the end of the RF signal can be suppressed.

＜実施の形態１に係る半導体光集積素子とドライバ回路との組み合わせの効果＞
　実施の形態１に係る半導体光集積素子５００とドライバ回路９０との組み合わせの構成によると、第１光変調部５及び第２光変調部６が並列に配置され、かつ対向する構成であるため、ＲＦ信号生成用のドライバ回路９０から出力されたＲＦ電気信号の減衰が比較的抑制されるので、半導体光集積素子５００の広帯域化が可能となるという効果を奏する。 <Effect of Combination of Semiconductor Optical Integrated Device and Driver Circuit According to First Embodiment>
According to the configuration of the combination of the semiconductor optical integrated element 500 and the driver circuit 90 of the first embodiment, the first optical modulation section 5 and the second optical modulation section 6 are arranged in parallel and facing each other, and therefore attenuation of the RF electrical signal output from the driver circuit 90 for generating an RF signal is relatively suppressed, thereby achieving the effect of enabling the semiconductor optical integrated element 500 to have a broadband.

　また、光変調部２０の終端側でのＲＦ信号の反射を抑制するために設ける終端抵抗９４を短い配線によって配置できるので、余分な浮遊容量などの発生を抑制できるため、半導体光集積素子５００の広帯域化が可能となるという効果を奏する。 Furthermore, the termination resistor 94, which is provided to suppress reflection of the RF signal at the termination side of the optical modulation section 20, can be placed using short wiring, which suppresses the generation of excess stray capacitance and the like, thereby achieving the effect of enabling the semiconductor optical integrated device 500 to have a wider bandwidth.

実施の形態２．
＜実施の形態２に係る半導体光集積素子の特徴＞
　図７は、実施の形態２に係る半導体光集積素子６００の構成を示す上面図である。実施の形態２に係る半導体光集積素子６００は、実施の形態１に係る半導体光集積素子５００の構成に加えて、第１受動型導波路３中に第１光増幅部１００及び第１位相調整部１１０が設けられ、第２受動型導波路４中に第２光増幅部１０１及び第２位相調整部１１１が設けられている点に特徴がある。以下、第１光増幅部１００及び第２光増幅部１０１を光増幅部と総称し、第１位相調整部１１０及び第２位相調整部１１１を位相調整部と総称する。 Embodiment 2.
<Features of the semiconductor optical integrated device according to the second embodiment>
7 is a top view showing the configuration of a semiconductor optical integrated device 600 according to the second embodiment. The semiconductor optical integrated device 600 according to the second embodiment is characterized in that, in addition to the configuration of the semiconductor optical integrated device 500 according to the first embodiment, a first optical amplification section 100 and a first phase adjustment section 110 are provided in the first passive waveguide 3, and a second optical amplification section 101 and a second phase adjustment section 111 are provided in the second passive waveguide 4. Hereinafter, the first optical amplification section 100 and the second optical amplification section 101 will be collectively referred to as optical amplification sections, and the first phase adjustment section 110 and the second phase adjustment section 111 will be collectively referred to as phase adjustment sections.

＜位相調整部の機能＞
　位相調整部は、電流を印加することにより、位相調整部コア層（図示せず）の屈折率を変化させて伝搬する光の位相を調整する機能を有する。実施の形態２に係る半導体光集積素子６００では光合波部９において合波する際の各変調光の相対的な位相の関係から出力光の光強度が決定される。例えば各変調光間の相対的な位相差をゼロとすると、光出力は最大となる。一方、各変調光間の相対的な位相差を１８０度とすると、光出力はゼロとなる。さらに、各変調光間の相対的な位相差を９０度とすると、光出力は１／２となる。 <Function of phase adjustment section>
The phase adjustment unit has a function of adjusting the phase of propagating light by applying a current to change the refractive index of the phase adjustment unit core layer (not shown). In the semiconductor optical integrated device 600 according to the second embodiment, the optical intensity of the output light is determined based on the relative phase relationship of each modulated light when multiplexed in the optical multiplexer 9. For example, if the relative phase difference between each modulated light is set to zero, the optical output is maximized. On the other hand, if the relative phase difference between each modulated light is set to 180 degrees, the optical output is zero. Furthermore, if the relative phase difference between each modulated light is set to 90 degrees, the optical output is halved.

　例えば各変調光間の相対的な位相差を９０度として光出力を１／２とした状態で、各光変調部に逆向きの電圧（ｐｕｓｈ－ｐｕｌｌ）が印加されるようなＲＦ電気信号を印加することにより、光出力強度１／２を中心として、光出力強度０～１までの任意の強度変調信号光を出力することが可能となる。 For example, by applying an RF electrical signal that applies reverse voltages (push-pull) to each optical modulation section while setting the relative phase difference between each modulated light beam to 90 degrees and the optical output to 1/2, it is possible to output an intensity-modulated signal beam with an optical output intensity of any value between 0 and 1, with the optical output intensity at 1/2 as the center.

＜光増幅部の機能＞
　光増幅部は、電流を印加することで光を増幅できるため、半導体光集積素子６００の出力光の光強度を増大させることが可能となる。 <Function of the optical amplifier>
The optical amplifier can amplify light by applying a current, and therefore can increase the optical intensity of the output light from the semiconductor optical integrated device 600 .

　半導体レーザ部の両端から出力されるレーザ光の強度が異なっていた場合、光合波部９で合波される際の消光比が劣化するという不具合が発生する。かかる不具合を改善するために、光合波部９において合波される各変調光の光強度が同一となるように光増幅部で調整することで、消光比の劣化を抑制することが可能となる。 If the intensities of the laser light output from both ends of the semiconductor laser unit are different, a problem occurs in which the extinction ratio deteriorates when the light is combined in the optical combiner 9. To improve this problem, the optical amplifier adjusts the optical intensity of each modulated light combined in the optical combiner 9 so that it is the same, thereby suppressing the deterioration of the extinction ratio.

　なお、実施の形態２に係る半導体光集積素子６００は、半導体レーザ部２の一端２ａに接続された第１受動型導波路３に第１光増幅部１００及び第１位相調整部１１０のいずれか１つまたは両方が設けられ、半導体レーザ部２の他端２ｂに接続された第２受動型導波路４に第２光増幅部１０１及び第２位相調整部１１１のいずれか１つまたは両方が設けられた構成であってもよい。 The semiconductor optical integrated device 600 according to the second embodiment may be configured such that either or both of the first optical amplifier 100 and the first phase adjuster 110 are provided in the first passive waveguide 3 connected to one end 2a of the semiconductor laser section 2, and either or both of the second optical amplifier 101 and the second phase adjuster 111 are provided in the second passive waveguide 4 connected to the other end 2b of the semiconductor laser section 2.

　また、実施の形態１に係る半導体光集積素子５００ではなく、実施の形態１の変形例に係る半導体光集積素子５５０に適用して、第１半導体レーザ部２２の一端２２ａに接続された第１受動型導波路３に第１光増幅部１００及び第１位相調整部１１０のいずれか１つまたは両方が設けられ、第２半導体レーザ部２３の一端２３ａに接続された第２受動型導波路４に第２光増幅部１０１及び第２位相調整部１１１のいずれか１つまたは両方が設けられた構成であってもよい。 Furthermore, instead of the semiconductor optical integrated device 500 according to embodiment 1, this may be applied to a semiconductor optical integrated device 550 according to a modified example of embodiment 1, in which either one or both of a first optical amplifier 100 and a first phase adjustment unit 110 are provided in the first passive waveguide 3 connected to one end 22a of the first semiconductor laser unit 22, and either one or both of a second optical amplifier 101 and a second phase adjustment unit 111 are provided in the second passive waveguide 4 connected to one end 23a of the second semiconductor laser unit 23.

＜実施の形態２に係る半導体光集積素子の効果＞
　以上、実施の形態２に係る半導体光集積素子によると、第１受動型導波路に第１光増幅部及び第１位相調整部を設け、第２受動型導波路に第２光増幅部及び第２位相調整部を設けたので、光出力強度０～１までの任意の強度変調信号光を出力することが可能であり、かつ、出力光の光強度を増加させることも可能である半導体光集積素子が得られるという効果を奏する。 <Effects of the semiconductor optical integrated device according to the second embodiment>
As described above, the semiconductor optical integrated device according to the second embodiment has a first optical amplification section and a first phase adjustment section provided in the first passive waveguide, and a second optical amplification section and a second phase adjustment section provided in the second passive waveguide, thereby achieving the effect of obtaining a semiconductor optical integrated device that is capable of outputting intensity-modulated signal light with an optical output intensity of any value between 0 and 1 and that is also capable of increasing the optical intensity of the output light.

実施の形態３．
＜実施の形態３に係る半導体光集積素子の特徴＞
　図８は、実施の形態３に係る半導体光集積素子７００の構成を示す上面図である。実施の形態３に係る半導体光集積素子７００は、基本的な構成は実施の形態１に係る半導体光集積素子５００と共通するが、第１受動型導波路１２０の導波路長Ｌ１と第２受動型導波路１２１の導波路長Ｌ２が等しい点に特徴がある。 Embodiment 3.
<Features of the semiconductor optical integrated device according to the third embodiment>
8 is a top view showing the configuration of a semiconductor optical integrated device 700 according to embodiment 3. The semiconductor optical integrated device 700 according to embodiment 3 has a basic configuration in common with the semiconductor optical integrated device 500 according to embodiment 1, but is characterized in that the waveguide length L1 of the first passive waveguide 120 and the waveguide length L2 of the second passive waveguide 121 are equal to each other.

　第１受動型導波路１２０の導波路長Ｌ１と第２受動型導波路１２１の導波路長Ｌ２の長さを等しくすることにより、各受動型導波路の伝搬損失を等しくすることが可能となるため、消光比の劣化を抑制することができる。別の効果として、半導体レーザ部２から出力されるレーザ光の波長が変動した場合であっても、安定した光出力が得られる。 By making the waveguide length L1 of the first passive waveguide 120 and the waveguide length L2 of the second passive waveguide 121 equal, it is possible to equalize the propagation loss of each passive waveguide, thereby suppressing deterioration of the extinction ratio. Another effect is that a stable optical output can be obtained even if the wavelength of the laser light output from the semiconductor laser unit 2 fluctuates.

　上述の各導波路長を等しくすることに加えて、各受動型導波路の等価屈折率も等しくする場合は、例えば光合波部９が２×１ＭＭＩ（Ｍｕｌｔｉ－Ｍｏｄｅ　Ｉｎｔｅｒｆｅｒｅｎｃｅ）である場合には、原理的に光合波部９で合波される光の位相が一致するため、最大の出力光、つまり光強度１の出力光が出力される。 If, in addition to making the lengths of the waveguides equal as described above, the equivalent refractive index of each passive waveguide is also equal, for example, if the optical multiplexer 9 is a 2x1 MMI (Multi-Mode Interference), then in principle the phases of the light multiplexed by the optical multiplexer 9 will match, and the maximum output light, that is, output light with a light intensity of 1, will be output.

　光合波部９が２×２ＭＭＩである場合は、各出力ポートの光強度はそれぞれ１／２となる。したがって、１／２の光強度を中心値として、ＲＦ信号の印加により光強度０～１の範囲の強度変調信号を出力できる。よって、２×１ＭＭＩでは、光強度の中心値を１／２とするために位相調整が必要になるが、２×２ＭＭＩとする場合には原理的に位相調整が不要となる。 When the optical multiplexer 9 is a 2x2 MMI, the optical intensity of each output port is 1/2. Therefore, with 1/2 optical intensity as the center value, an intensity-modulated signal with an optical intensity range of 0 to 1 can be output by applying an RF signal. Therefore, with a 2x1 MMI, phase adjustment is required to set the center value of the optical intensity to 1/2, but with a 2x2 MMI, phase adjustment is theoretically not necessary.

　実施の形態３に係る半導体光集積素子７００において、基本的な構成を実施の形態２に係る半導体光集積素子６００とする場合は、以下のように構成すればよい。 If the semiconductor optical integrated device 700 according to embodiment 3 has the same basic configuration as the semiconductor optical integrated device 600 according to embodiment 2, it can be configured as follows.

　半導体光集積素子７００の第１受動型導波路３に第１光増幅部１００、第２受動型導波路４に第２光増幅部１０１がそれぞれ設けられた場合は、第１受動型導波路３及び第１光増幅部１００の長さの合計が、第２受動型導波路４及び第２光増幅部１０１の長さの合計に等しければよい。 When the first optical amplifier 100 is provided in the first passive waveguide 3 and the second optical amplifier 101 is provided in the second passive waveguide 4 of the semiconductor optical integrated device 700, the total length of the first passive waveguide 3 and the first optical amplifier 100 should be equal to the total length of the second passive waveguide 4 and the second optical amplifier 101.

　半導体光集積素子７００の第１受動型導波路３に第１位相調整部１１０、第２受動型導波路４に第２位相調整部１１１がそれぞれ設けられた場合は、第１受動型導波路３及び第１位相調整部１１０の長さの合計が、第２受動型導波路４及び第２位相調整部１１１の長さの合計に等しければよい。 When the first passive waveguide 3 of the semiconductor optical integrated device 700 is provided with a first phase adjustment unit 110 and the second passive waveguide 4 is provided with a second phase adjustment unit 111, the total length of the first passive waveguide 3 and the first phase adjustment unit 110 should be equal to the total length of the second passive waveguide 4 and the second phase adjustment unit 111.

　半導体光集積素子７００の第１受動型導波路３に第１光増幅部１００及び第１位相調整部１１０、第２受動型導波路４に第２光増幅部１０１及び第２位相調整部１１１がそれぞれ設けられた場合は、第１受動型導波路３、第１光増幅部１００及び第１位相調整部１１０の長さの合計が、第２受動型導波路４、第２光増幅部１０１及び第２位相調整部１１１の長さの合計に等しければよい。 When the first passive waveguide 3 of the semiconductor optical integrated device 700 is provided with the first optical amplifier 100 and the first phase adjustment unit 110, and the second passive waveguide 4 is provided with the second optical amplifier 101 and the second phase adjustment unit 111, the total length of the first passive waveguide 3, the first optical amplifier 100, and the first phase adjustment unit 110 should be equal to the total length of the second passive waveguide 4, the second optical amplifier 101, and the second phase adjustment unit 111.

＜実施の形態３に係る半導体光集積素子の効果＞
　以上、実施の形態３に係る半導体光集積素子によると、第１受動型導波路の導波路長と第２受動型導波路の導波路長の長さを等しくしたので、消光比の劣化の抑制が可能であり、かつ、半導体レーザ部から出力されるレーザ光の波長が変動した場合であっても、安定した光出力が実現できる半導体光集積素子が得られるという効果を奏する。 <Effects of the semiconductor optical integrated device according to the third embodiment>
As described above, according to the semiconductor optical integrated device of the third embodiment, the waveguide length of the first passive waveguide and the waveguide length of the second passive waveguide are made equal to each other, and therefore it is possible to suppress deterioration of the extinction ratio, and it is possible to obtain an advantageous effect of obtaining a semiconductor optical integrated device that can achieve stable optical output even when the wavelength of the laser light output from the semiconductor laser unit fluctuates.

実施の形態３の変形例．
＜実施の形態３の変形例に係る半導体光集積素子の特徴＞
　図９は、実施の形態３の変形例に係る半導体光集積素子７５０の構成を示す上面図である。実施の形態３の変形例に係る半導体光集積素子７５０では、第１受動型導波路１３０の湾曲部分Ｃ１の個数Ｎ１と第２受動型導波路１３１の湾曲部分Ｃ２の個数Ｎ２の個数が等しい点に特徴がある。なお、図９中において、各湾曲部分は、便宜上、受動型導波路が直角に曲がる形状で描いている。 Variant of embodiment 3.
<Features of the semiconductor optical integrated device according to the modification of the third embodiment>
9 is a top view showing the configuration of a semiconductor optical integrated device 750 according to a modification of the third embodiment. The semiconductor optical integrated device 750 according to the modification of the third embodiment is characterized in that the number N1 of the curved portions C1 of the first passive waveguide 130 is equal to the number N2 of the curved portions C2 of the second passive waveguide 131. For convenience, each curved portion in FIG. 9 is depicted as if the passive waveguide is bent at a right angle.

＜実施の形態３の変形例に係る半導体光集積素子の効果＞
　以上、実施の形態３の変形例に係る半導体光集積素子では、上述の構成とすることにより、第１受動型導波路と第２受動型導波路の間で湾曲部分による放射損失を等しくすることができるため、消光比の劣化を抑制できる半導体光集積素子が得られるという効果を奏する。 <Effects of the semiconductor optical integrated device according to the modification of the third embodiment>
As described above, in the semiconductor optical integrated device according to the modification of the third embodiment, the above-described configuration makes it possible to equalize the radiation loss due to the curved portions between the first passive waveguide and the second passive waveguide, thereby achieving an effect of obtaining a semiconductor optical integrated device that can suppress deterioration of the extinction ratio.

実施の形態４．
＜実施の形態４に係る半導体光集積素子の特徴＞
　図１０は、実施の形態４に係る半導体光集積素子８００の構成を示す上面図である。実施の形態４に係る半導体光集積素子８００は、実施の形態１の変形例に係る半導体光集積素子５５０の構成に加えて、第１半導体レーザ部１５１の他端１５１ｂに第１モニタ用受光部１７１が設けられ、第２半導体レーザ部１５２の他端１５２ｂに第２モニタ用受光部１７２が設けられている点に特徴がある。以下の説明では、第１モニタ用受光部１７１及び第２モニタ用受光部１７２を、モニタ用受光部１７３と総称する。 Embodiment 4.
<Features of the semiconductor optical integrated device according to the fourth embodiment>
10 is a top view showing the configuration of a semiconductor optical integrated device 800 according to the fourth embodiment. The semiconductor optical integrated device 800 according to the fourth embodiment is characterized in that, in addition to the configuration of the semiconductor optical integrated device 550 according to the modified example of the first embodiment, a first monitor light-receiving portion 171 is provided at the other end 151 b of the first semiconductor laser portion 151, and a second monitor light-receiving portion 172 is provided at the other end 152 b of the second semiconductor laser portion 152. In the following description, the first monitor light-receiving portion 171 and the second monitor light-receiving portion 172 are collectively referred to as a monitor light-receiving portion 173.

　実施の形態４に係る半導体光集積素子８００は、半導体基板１上に設けられた、第１半導体レーザからなる第１半導体レーザ部１５１と、第２半導体レーザからなる第２半導体レーザ部１５２と、第１半導体レーザ部１５１の一端１５１ａに一端が接続された第１受動型導波路３と、第１半導体レーザ部１５１の他端１５１ｂに接続された第１モニタ用受光部１７１と、第２半導体レーザ部１５２の一端１５２ａに一端が接続された第２受動型導波路４と、第２半導体レーザ部１５２の他端１５２ｂに接続された第２モニタ用受光部１７２と、第１受動型導波路３の他端に一端５ａが接続された第１光変調部５と、第２受動型導波路４の他端に一端６ａが接続された第２光変調部６と、第１光変調部５の他端５ｂに一端が接続された第３受動型導波路７と、第２光変調部６の他端６ｂに一端が接続された第４受動型導波路８と、第３受動型導波路７の他端及び第４受動型導波路８の他端に一端９ａが接続された光合波部９と、光合波部９の他端９ｂが接続された光出力部１０と、を備える。 The semiconductor optical integrated device 800 according to the fourth embodiment includes a first semiconductor laser section 151 formed on a semiconductor substrate 1 and consisting of a first semiconductor laser, a second semiconductor laser section 152 formed on a second semiconductor laser, a first passive waveguide 3 having one end connected to one end 151a of the first semiconductor laser section 151, a first monitor light receiving section 171 connected to the other end 151b of the first semiconductor laser section 151, a second passive waveguide 4 having one end connected to one end 152a of the second semiconductor laser section 152, and a second passive waveguide 5 having one end connected to the other end 151b of the second semiconductor laser section 152. 2b, a first optical modulation unit 5 having one end 5a connected to the other end of the first passive waveguide 3, a second optical modulation unit 6 having one end 6a connected to the other end of the second passive waveguide 4, a third passive waveguide 7 having one end connected to the other end 5b of the first optical modulation unit 5, a fourth passive waveguide 8 having one end connected to the other end 6b of the second optical modulation unit 6, an optical multiplexer 9 having one end 9a connected to the other end of the third passive waveguide 7 and the other end of the fourth passive waveguide 8, and an optical output unit 10 having the other end 9b of the optical multiplexer 9 connected.

　半導体基板１上に形成した複数の半導体レーザ部の間の特性のばらつきによって、各半導体レーザ部に印加する電流値が同じ場合であっても、各半導体レーザ部で光出力強度が異なる不具合が発生する場合がある。実施の形態４に係る半導体光集積素子８００では、各半導体レーザ部１５１、１５２にそれぞれモニタ用受光部を配置することにより、各半導体レーザ部１５１、１５２の光出力強度をモニタして、各半導体レーザ部１５１、１５２に印加する電流値を個別に調整することにより、光出力強度を同一にできる。この結果、半導体光集積素子の消光比の劣化を抑制できる。 Due to variations in the characteristics among multiple semiconductor laser units formed on the semiconductor substrate 1, problems may occur in which the optical output intensity differs among the semiconductor laser units even when the same current value is applied to each semiconductor laser unit. In the semiconductor optical integrated device 800 according to embodiment 4, by arranging a monitor light receiving unit in each semiconductor laser unit 151, 152, the optical output intensity of each semiconductor laser unit 151, 152 can be monitored and the current value applied to each semiconductor laser unit 151, 152 can be individually adjusted to make the optical output intensity the same. As a result, deterioration of the extinction ratio of the semiconductor optical integrated device can be suppressed.

＜モニタ用受光部の構成＞
　図１１は、実施の形態４に係る半導体光集積素子８００におけるモニタ用受光部１７３の断面図である。なお、図１１は、モニタ用受光部１７３の光の伝搬方向に直交する面での断面図を表す。 <Configuration of monitor light receiving unit>
11 is a cross-sectional view of the monitor light-receiving portion 173 in the semiconductor optical integrated device 800 according to the fourth embodiment. Note that Fig. 11 shows a cross-sectional view of the monitor light-receiving portion 173 taken along a plane perpendicular to the propagation direction of light.

　モニタ用受光部１７３は、半導体基板１上に形成されたｎ型下部クラッド層１６１の一部と、光吸収コア層１６２と、ｐ型上部クラッド層１６３と、ｐ型コンタクト層１６４がストライプ状に形成されたハイメサ型構造１６５と、ｐ型コンタクト層１６４の上面に形成された受光部電極１６７と、少なくともハイメサ型構造１６５の側面部を覆う保護絶縁膜１６８と、ハイメサ型構造１６５から離間してｎ型下部クラッド層１６１上に形成されたｎ型コンタクト層１６９と、ｎ型コンタクト層１６９上に設けられた下側電極１７０と、で構成されている。 The monitor light receiving section 173 is composed of a portion of the n-type lower cladding layer 161 formed on the semiconductor substrate 1, a light absorbing core layer 162, a p-type upper cladding layer 163, a high mesa structure 165 in which the p-type contact layer 164 is formed in a striped pattern, a light receiving section electrode 167 formed on the upper surface of the p-type contact layer 164, a protective insulating film 168 covering at least the side surface of the high mesa structure 165, an n-type contact layer 169 formed on the n-type lower cladding layer 161 and spaced apart from the high mesa structure 165, and a lower electrode 170 provided on the n-type contact layer 169.

　光吸収コア層１６２として、実施の形態１の変形例に係る半導体光集積素子５５０の第１半導体レーザ部２２及び第２半導体レーザ部２３において形成されている利得コア層４２と同一の構造を適用している。しかしながら、半導体レーザ部のような埋め込み型構造とはしておらず、光変調部２０と同様なハイメサ型構造１６５としている。 The optical absorption core layer 162 has the same structure as the gain core layer 42 formed in the first semiconductor laser section 22 and the second semiconductor laser section 23 of the semiconductor optical integrated device 550 according to the modified example of embodiment 1. However, it does not have a buried structure like the semiconductor laser section, but rather has a high mesa structure 165 similar to the optical modulation section 20.

　半導体レーザ部では順方向電流を印加して内部を伝搬する光を増幅させるため、コア層を、特に利得コア層４２と呼んでいる。実施の形態４におけるモニタ用受光部１７３のコア層は、半導体レーザ部と同一のコア層を配置しているが、光を吸収するためのコア層なので、実施の形態４では特に光吸収コア層１６２と呼ぶ。 In the semiconductor laser section, a forward current is applied to amplify the light propagating inside, so the core layer is specifically referred to as the gain core layer 42. The core layer of the monitor light receiving section 173 in embodiment 4 is the same as that of the semiconductor laser section, but since it is a core layer for absorbing light, it is specifically referred to as the light absorption core layer 162 in embodiment 4.

　光吸収コア層１６２は、逆バイアスを印加することで入力された光の強度に比例した光電流を流す機能を有する。ｎ型下部クラッド層１６１及びｐ型上部クラッド層１６３は、光吸収コア層１６２に光を閉じ込めるため、光吸収コア層１６２よりも低い屈折率の半導体層で構成されている。ｐ型コンタクト層１６４は、抵抗を小さくするため、ｐ型上部クラッド層１６３よりも低抵抗である半導体層で構成される。 The light absorbing core layer 162 has the function of passing a photocurrent proportional to the intensity of the input light when a reverse bias is applied. The n-type lower cladding layer 161 and p-type upper cladding layer 163 are composed of semiconductor layers with a lower refractive index than the light absorbing core layer 162 in order to confine light in the light absorbing core layer 162. The p-type contact layer 164 is composed of a semiconductor layer with a lower resistance than the p-type upper cladding layer 163 in order to reduce resistance.

　保護絶縁膜１６８は、酸化膜または窒化膜などの無機絶縁膜、あるいはＢＣＢなどの有機絶縁膜からなる絶縁性材料で構成される。保護絶縁膜１６８は、雰囲気中の酸素、水などにより半導体が酸化すること、あるいは変質することを防止する機能を有する。 The protective insulating film 168 is made of an insulating material, such as an inorganic insulating film such as an oxide film or a nitride film, or an organic insulating film such as BCB. The protective insulating film 168 functions to prevent the semiconductor from being oxidized or altered by oxygen, water, etc. in the atmosphere.

＜モニタ用受光部の製造方法＞
　モニタ用受光部１７３の製造方法について、以下に説明する。半導体基板１上に、層厚２０００ｎｍのｎ型ＩｎＰ層で構成されたｎ型下部クラッド層１６１と、層厚の合計が１００ｎｍのＡｌＧａＩｎＡｓからなる多重量子井戸層で構成された光吸収コア層１６２と、層厚２０００ｎｍのｐ型ＩｎＰ層で構成されたｐ型上部クラッド層１６３と、層厚３００ｎｍのｐ型ＩｎＧａＡｓ層で構成されたｐ型コンタクト層１６４とを、ＭＯＣＶＤ法を用いて順次エピタキシャル結晶成長する。 <Method of manufacturing the monitor light receiving unit>
The following describes a method for manufacturing the monitor light receiving section 173. On the semiconductor substrate 1, the following are epitaxially grown in sequence by MOCVD: an n-type lower cladding layer 161 made of an n-type InP layer with a layer thickness of 2000 nm, a light absorbing core layer 162 made of an AlGaInAs multiple quantum well layer with a total layer thickness of 100 nm, a p-type upper cladding layer 163 made of a p-type InP layer with a layer thickness of 2000 nm, and a p-type contact layer 164 made of a p-type InGaAs layer with a layer thickness of 300 nm.

　エピタキシャル結晶成長後、各半導体層をＲＩＥ法などにより選択的にエッチングして、ハイメサ型構造１６５を形成する。ｐ型コンタクト層１６４上に、Ｔｉ、Ａｕ、Ｐｔ、Ｎｂ、Ｎｉなどの金属で構成された受光部電極１６７を形成し、半導体表面を保護するための保護絶縁膜１６８を構成する膜厚３００ｎｍのＳｉＯ₂膜を、ＣＶＤ法などの成膜方法により形成する。 After epitaxial crystal growth, each semiconductor layer is selectively etched by RIE or the like to form a high mesa structure 165. A light-receiving electrode 167 made of a metal such as Ti, Au, Pt, Nb, or Ni is formed on the p-type contact layer 164, and a 300-nm-thick _SiO2 film that constitutes a protective insulating film 168 for protecting the semiconductor surface is formed by a film-forming method such as CVD.

　上述の構成において、光吸収コア層１６２の多重量子井戸層は、光吸収に寄与する井戸層と、井戸層よりバンドギャップが大きいバリア層とのペアの繰り返しで構成され、例えば８ペアとする。なお、上述の構成において、ｎ型下部クラッド層１６１は、半導体レーザ部及び受動型導波路のｎ型下部クラッド層と共通化することができる。 In the above-described configuration, the multiple quantum well layer of the light absorption core layer 162 is composed of repeated pairs of well layers that contribute to light absorption and barrier layers with a larger band gap than the well layers, for example, eight pairs. In the above-described configuration, the n-type lower cladding layer 161 can be shared with the n-type lower cladding layer of the semiconductor laser section and the passive waveguide.

＜実施の形態４に係る半導体光集積素子の効果＞
　以上、実施の形態４に係る半導体光集積素子では、各半導体レーザ部にそれぞれモニタ用受光部を配置することにより各半導体レーザ部の光出力強度をモニタし、各半導体レーザ部に印加する電流値を個別に調整することにより光出力強度を同一にできるので、消光比の劣化の抑制が可能な半導体光集積素子を得ることができるという効果を奏する。 <Effects of the semiconductor optical integrated device according to the fourth embodiment>
As described above, in the semiconductor optical integrated device according to the fourth embodiment, by disposing a monitor light receiving section in each semiconductor laser section, the optical output intensity of each semiconductor laser section can be monitored, and by individually adjusting the current value applied to each semiconductor laser section, the optical output intensities can be made uniform, thereby providing an advantageous effect of obtaining a semiconductor optical integrated device capable of suppressing deterioration of the extinction ratio.

　本開示は、様々な例示的な実施の形態及び実施例が記載されているが、１つ、または複数の実施の形態に記載された様々な特徴、態様、及び機能は特定の実施の形態の適用に限られるのではなく、単独で、または様々な組み合わせで実施の形態に適用可能である。 Although this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.

　従って、例示されていない無数の変形例が、本開示の技術の範囲内において想定される。例えば、少なくとも１つの構成要素を変形する場合、追加する場合または省略する場合、さらには、少なくとも１つの構成要素を抽出し、他の実施の形態の構成要素と組み合わせる場合が含まれるものとする。 Therefore, countless variations not illustrated are contemplated within the scope of the technology of this disclosure. For example, these include cases in which at least one component is modified, added, or omitted, and even cases in which at least one component is extracted and combined with components of another embodiment.

１　半導体基板、２　半導体レーザ部、２ａ、５ａ、６ａ、９ａ、２２ａ、２３ａ、１５１ａ、１５２ａ　一端、２ｂ、５ｂ、６ｂ、９ｂ、１５１ｂ、１５２ｂ　他端、３、１２０、１３０　第１受動型導波路、４、１２１、１３１　第２受動型導波路、５　第１光変調部、６　第２光変調部、７　第３受動型導波路、８　第４受動型導波路、９　光合波部、１０　光出力部、２０　光変調部、２２、１５１　第１半導体レーザ部、２３、１５２　第２半導体レーザ部、３０　受動型導波路、４１、６１、８１、１６１　ｎ型下部クラッド層、４２　利得コア層、４３、６３、１６３　ｐ型上部クラッド層、４５　電流ブロック層、４５ａ　ｐ型電流ブロック層、４５ｂ　ｎ型電流ブロック層、４６、６４、１６４　ｐ型コンタクト層、４７　レーザ部電極、４８、６８、８８、１６８　保護絶縁膜、４９、６９、１６９　ｎ型コンタクト層、５０、７０、１７０　下側電極、５５、６５、８５、１６５　ハイメサ型構造、６２　光変調コア層、６７　光変調部電極、８３　ｉ型上部クラッド層、９０　ドライバ回路、９１　電極パッド、９２　ワイヤ、９３　ＲＦ信号入力用配線部、９４　終端抵抗、１００　第１光増幅部、１０１　第２光増幅部、１１０　第１位相調整部、１１１　第２位相調整部、１６２　光吸収コア層、１６７　受光部電極、１７１　第１モニタ用受光部、１７２　第２モニタ用受光部、１７３　モニタ用受光部、５００、５５０、６００、７００、７５０，８００　半導体光集積素子、Ｃ１、Ｃ２　湾曲部分、Ｌ１、Ｌ２　導波路長 1. Semiconductor substrate, 2. Semiconductor laser section, 2a, 5a, 6a, 9a, 22a, 23a, 151a, 152a. One end, 2b, 5b, 6b, 9b, 151b, 152b. Other end, 3, 120, 130. First passive waveguide, 4, 121, 131. Second passive waveguide, 5. First optical modulation section, 6. Second optical modulation section, 7. Third passive waveguide, 8. Fourth passive waveguide, 9. Optical multiplexing section, 10. Optical output section, 20: Optical modulation section, 22, 151: First semiconductor laser section, 23, 152: Second semiconductor laser section, 30: Passive waveguide, 41, 61, 81, 161: N-type lower cladding layer, 42: Gain core layer, 43, 63, 163: P-type upper cladding layer, 45: Current blocking layer, 45a: P-type current blocking layer, 45b: N-type current blocking layer, 46, 64, 164: P-type contact Layer, 47: Laser electrode, 48, 68, 88, 168: Protective insulating film, 49, 69, 169: N-type contact layer, 50, 70, 170: Lower electrode, 55, 65, 85, 165: High mesa structure, 62: Optical modulation core layer, 67: Optical modulation electrode, 83: I-type upper cladding layer, 90: Driver circuit, 91: Electrode pad, 92: Wire, 93: RF signal input wiring section, 94: Termination Resistor, 100: First optical amplifier, 101: Second optical amplifier, 110: First phase adjustment unit, 111: Second phase adjustment unit, 162: Light absorption core layer, 167: Light receiving electrode, 171: First monitor light receiving unit, 172: Second monitor light receiving unit, 173: Monitor light receiving unit, 500, 550, 600, 700, 750, 800: Semiconductor optical integrated element, C1, C2: Curved portion, L1, L2: Waveguide length

Claims

a semiconductor laser portion formed on a substrate and made of a semiconductor laser;
an optical modulation section formed on the substrate, the optical modulation section including a first optical modulation section having one end connected to one end of the semiconductor laser section via a first passive waveguide, and a second optical modulation section having one end connected to the other end of the semiconductor laser section via a second passive waveguide;
A semiconductor optical integrated device comprising:

The semiconductor optical integrated device described in claim 1, characterized in that the longitudinal direction of the semiconductor laser section is parallel to the longitudinal directions of the first optical modulation section and the second optical modulation section.

The semiconductor optical integrated device according to claim 1 or 2, characterized in that either one or both of a first optical amplifier and a first phase adjustment unit are provided in the first passive waveguide connected to one end of the semiconductor laser unit, and either one or both of a second optical amplifier and a second phase adjustment unit are provided in the second passive waveguide connected to the other end of the semiconductor laser unit.

a first semiconductor laser unit formed on a substrate and including a first semiconductor laser;
a second semiconductor laser unit formed on the substrate and consisting of a second semiconductor laser;
an optical modulation section formed on the substrate, the optical modulation section comprising: a first optical modulation section having one end connected to one end of the first semiconductor laser section via a first passive waveguide and disposed at a position facing the first semiconductor laser section; and a second optical modulation section having one end connected to one end of the second semiconductor laser section via a second passive waveguide and disposed at a position facing the second semiconductor laser section;
A semiconductor optical integrated device comprising:

The semiconductor optical integrated device described in claim 4, characterized in that the longitudinal direction of the first semiconductor laser section and the longitudinal direction of the first optical modulation section are parallel, and the longitudinal direction of the second semiconductor laser section and the longitudinal direction of the second optical modulation section are parallel.

The semiconductor optical integrated device described in claim 4 or 5, characterized in that either one or both of a first optical amplifier and a first phase adjustment unit are provided in the first passive waveguide connected to one end of the first semiconductor laser unit, and either one or both of a second optical amplifier and a second phase adjustment unit are provided in the second passive waveguide connected to one end of the second semiconductor laser unit.

The semiconductor optical integrated device described in any one of claims 1, 2, 4, and 5, characterized in that the waveguide length L1 of the first passive waveguide and the waveguide length L2 of the second passive waveguide are equal.

When the first optical amplifier is provided in the first passive waveguide and the second optical amplifier is provided in the second passive waveguide, the total length of the first passive waveguide and the first optical amplifier is equal to the total length of the second passive waveguide and the second optical amplifier, and when the first phase adjustment unit is provided in the first passive waveguide and the second phase adjustment unit is provided in the second passive waveguide, the total length of the first passive waveguide and the first phase adjustment unit is equal to the total length of the second passive waveguide. The semiconductor optical integrated device according to claim 3 or 6, characterized in that when the first passive waveguide is provided with the first optical amplifier and the first phase adjuster, and the second passive waveguide is provided with the second optical amplifier and the second phase adjuster, the total length of the first passive waveguide, the first optical amplifier, and the first phase adjuster is equal to the total length of the second passive waveguide, the second optical amplifier, and the second phase adjuster.

The semiconductor optical integrated device described in any one of claims 4 to 6, further comprising a first monitor light receiving unit connected to the other end of the first semiconductor laser unit and receiving the optical output of the first semiconductor laser, and a second monitor light receiving unit connected to the other end of the second semiconductor laser unit and receiving the optical output of the second semiconductor laser.

A semiconductor optical integrated device described in any one of claims 1 to 9, characterized in that the number of curved portions C1 of the first passive waveguide is equal to the number of curved portions C2 of the second passive waveguide.