CN106461874B - Arrayed waveguide grating and tunable laser with the arrayed waveguide grating - Google Patents

Abstract

An arrayed waveguide grating (30) and a tunable laser (1000) having the arrayed waveguide grating (30), the arrayed waveguide grating (30) includes an input coupler (31), a first arrayed waveguide region (33) and a second Two arrayed waveguide regions (34), the first arrayed waveguide region (33) includes a plurality of first waveguides (331), and adjacent first waveguides (331) have a first optical path difference, the first waveguides The second array waveguide area (34) includes a plurality of second waveguides (341), and the adjacent second waveguides (341) have a second optical path difference, wherein the first optical path difference is not equal to the first Two optical path differences.

Description

Arrayed waveguide grating and tunable laser with the arrayed waveguide grating

technical field

The invention relates to the field of optical communication, in particular to an arrayed waveguide grating and a tunable laser with the arrayed waveguide grating.

Background technique

Large-capacity high-speed optical transmission and more flexible optical network structure are the development trend of optical communication. At present, the 100G technology using high-order modulation and coherent reception has entered the commercial stage and has become one of the trends in the industry. With the deployment of 100G coherent systems, the first-generation standard optical modules cannot meet the requirements in terms of size and power consumption, and have become a bottleneck for improving the integration density of optical modules. Therefore, the development of optical modules with miniaturization and low power consumption is of great significance.

At present, an existing solution is to use planar optical waveguide technology to manufacture core optical devices in optical modules, such as lasers, modulators, receivers, etc., so as to achieve miniaturization and low power consumption. Among them, tunable laser based on planar optical waveguide technology is one of the key technologies. Currently, several tunable lasers based on planar optical waveguide technology have been developed in the industry, such as a tunable laser based on an array waveguide grating (array waveguide grating, AWG) structure. However, most of these tunable lasers have problems such as high requirements on the manufacturing process, high manufacturing costs, difficulty in achieving continuous wavelength tuning, and limited tuning range, which cannot meet the use requirements.

Contents of the invention

In view of this, the object of the present invention is to provide an arrayed waveguide grating and a tunable laser with the arrayed waveguide grating. The tunable laser can be manufactured on a planar optical waveguide, and has high integration, simple manufacturing process, and wavelength Large adjustable range and other advantages.

In a first aspect, an arrayed waveguide grating is provided, including an input coupler, a first arrayed waveguide area, and a second arrayed waveguide area, the first arrayed waveguide area includes a plurality of first waveguides, and the adjacent first The waveguide has a first optical path difference, the second arrayed waveguide region includes a plurality of second waveguides, and the adjacent second waveguides have a second optical path difference, wherein the first optical path difference is not equal to the The second optical path difference.

In a first possible implementation manner of the first aspect, the arrayed waveguide grating further includes a first electrode, the first electrode is electrically connected to the plurality of first waveguides, and the first electrode is used for The plurality of first waveguides apply a voltage to modulate the first optical path difference.

In a second possible implementation manner of the first aspect, the arrayed waveguide grating further includes a second electrode, the second electrode is electrically connected to the plurality of second waveguides, and the second electrode is used for The plurality of second waveguides apply a voltage to modulate the second optical path difference.

In the second aspect, a tunable laser is provided, including a reflective element, a reflective-transmissive element, a gain medium, and the arrayed waveguide grating, the arrayed waveguide grating and the gain medium are arranged on the reflective element and the reflective-transmissive between components.

In a first possible implementation manner of the second aspect, one end of the plurality of first waveguides and the plurality of second waveguides of the arrayed waveguide grating is disposed on the reflective element, and the other end is coupled to the input coupler , the first light beam is distributed to the plurality of first waveguides and the plurality of second waveguides for transmission through the input coupler, and is reflected by the reflective element to the input coupler to generate the second waveguide light beam, and the input coupler outputs the second light beam.

In a second possible implementation manner of the second aspect, the reflective element is composed of waveguide reflective structures integrated on the multiple first waveguides and the multiple second waveguides.

In a third possible implementation manner of the second aspect, the arrayed waveguide grating further includes an output coupler, and one end of the plurality of first waveguides and the plurality of second waveguides of the arrayed waveguide grating is connected to the output coupler coupled, and the other end is coupled to the input coupler.

In a fourth possible implementation manner of the second aspect, the tunable laser further includes a phase modulator, and the phase modulator is disposed between the reflective element and the reflective transmissive element.

In a fifth possible implementation manner of the second aspect, the phase modulator covers the first planar optical waveguide with a metal electrode, and applies a current to the metal electrode to change the The refractive index is obtained; or,

The phase modulator covers the metal electrode on the first planar optical waveguide, and changes the doping and refractive index of the predetermined phase modulating material fabricated on the phase modulator by applying a current on the metal electrode get.

In a sixth possible implementation manner of the second aspect, the tunable laser further includes a second planar optical waveguide, the gain medium and the reflective element are fabricated on the second planar optical waveguide, and the array The waveguide grating, the phase modulator, and the reflection-transmission element are fabricated on the first planar optical waveguide; or,

The gain medium and the reflective and transmissive elements are fabricated on the second planar optical waveguide, and the arrayed waveguide grating, phase modulator and reflective element are fabricated on the first planar optical waveguide.

In a seventh possible implementation manner of the second aspect, a lens is disposed between the first planar optical waveguide and the second planar optical waveguide.

In the tunable laser provided by the embodiment of the present invention, by designing a waveguide array grating with two different optical path differences, the mode selection of the input first light beam is realized to output a second light beam containing only one wavelength light beam, the wavelength of the second light beam can also be adjusted by covering the first electrode and the second electrode on the waveguide array grating, realizing the effect of continuously adjustable wavelength. The tunable laser provided by the present invention can be integrally manufactured on a planar optical waveguide, so it has the advantages of high integration, small volume, large wavelength adjustment range, and low requirements for process manufacturing, which meets the needs of large-capacity, high-speed optical transmission and new technologies. Requirements for the use of a generation of optical devices.

Description of drawings

In order to illustrate the technical solution of the present invention more clearly, the accompanying drawings used in the implementation will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some implementations of the present invention. As far as the skilled person is concerned, other drawings can also be obtained based on these drawings on the premise of not paying creative work.

FIG. 1 is a schematic structural diagram of a tunable laser provided by a first embodiment of the present invention.

FIG. 2 is a schematic structural diagram of the arrayed waveguide grating shown in FIG. 1 .

FIG. 3 is a block diagram of the arrayed waveguide grating shown in FIG. 1 .

Fig. 4 is a schematic diagram of transmission peaks of arrayed waveguide gratings under different optical path differences.

Fig. 5 is a schematic diagram of overlapping transmission peaks output by an arrayed waveguide grating according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of another structure of the tunable laser shown in FIG. 1 .

Fig. 7 is a schematic structural diagram of the tunable laser provided by the second embodiment of the present invention.

Fig. 8 is a schematic structural diagram of a tunable laser provided by a third embodiment of the present invention.

Fig. 9 is a schematic structural diagram of a tunable laser provided by a fourth embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Please refer to FIG. 1 . FIG. 1 is a tunable laser 1000 provided by a first embodiment of the present invention, which can be fabricated in a first planar optical waveguide 100 . The tunable laser 1000 includes a reflective element 10 , a reflective transmissive element 20 , an array waveguide grating (array waveguide grating, AWG) 30 and a gain medium 40 . Wherein, the reflective element 10, the reflective transmissive element 20, the arrayed waveguide grating 30, and the gain medium 40 can all be etched, photolithography, and doped in different regions of the first planar optical waveguide 100 , Cleavage, coating or ion implantation and other methods to obtain.

In the embodiment of the present invention, the reflective element 10 and the reflective-transmissive element 20 form a resonant cavity, and the arrayed waveguide grating 30 and the gain medium 40 are disposed in the resonant cavity. The arrayed waveguide grating 30 is disposed between the reflective element 10 and the reflection-transmissive element 20 , and the gain medium 40 is disposed between the reflective element 10 and the arrayed waveguide grating 30 . The gain medium 40 emits a first light beam including multiple wavelengths (or continuous wavelengths) under the pumping of a pumping source. The first light beam enters the arrayed waveguide grating 30, and the arrayed waveguide grating 30 demultiplexes (or filters) the first light beam to output a second light beam including only one wavelength, and the output The wavelength of the second light beam can be adjusted by adjusting the waveguide refractive index of the arrayed waveguide grating 30 . The second light beam propagates back and forth in the resonant cavity formed by the reflective element 10 and the transmissive element 20 , and passes through the arrayed waveguide grating 30 and the gain medium 40 during the propagation. When the second light beam satisfies both the amplitude condition and the phase condition of oscillation in the resonant cavity, the second light beam can be stably transmitted in the resonant cavity. Wherein, the amplitude condition requires the gain of the second light beam to go back and forth once in the resonator (the gain is generated by the gain medium 40, and when the second light beam passes through the gain medium 40, due to the stimulated radiation effect, the gain The medium 40 produces laser light with the same frequency and phase as the second light beam, so that the second light beam can obtain a gain) not less than the loss (the loss includes the transmission of the second light beam through the reflective element 10 and the reflection-transmissive element 20 The loss generated by the second light beam in the resonator due to scattering, diffraction and other absorption losses). Wherein, the light transmitted by the second light beam through the reflective transmissive element 20 is the output light. The phase condition requires that the phase change of the second light beam to and fro in the resonant cavity be an integer multiple of 2π.

In the embodiment of the present invention, the reflective element 10 can be obtained by cleaving one end face of the first planar optical waveguide 100 (the property that a mineral crystal often breaks in a certain direction after being stressed and produces a smooth plane is called cleavage, the above-mentioned end face is a smooth plane), which has a high reflectivity for the second light beam. Wherein, in order to make the reflective element 10 have a higher reflectivity to the second light beam, a reflective film can also be coated on the end face after cleavage, so as to ensure that a larger part of the second light beam passes through the reflective element 10. is reflected on. Correspondingly, the reflective and transmissive element 20 can also be obtained by cleaving the other end surface of the first planar light waveguide 100 opposite to the reflective element 10, and the reflective and transmissive element 20 can simultaneously transmit and reflect all The second light beam, and the proportion of the second light beam being transmitted and reflected can be adjusted by coating the reflective and transmissive element 20 with a corresponding proportion of reflective film or transmissive film according to actual needs. The reflective element 10 and the reflective lens element 20 together constitute a resonant cavity of the tunable laser 1000 .

It should be noted that, in other embodiments of the present invention, the reflective element 10 and the reflective-transmissive element 20 can also use independent optical devices, such as reflectors or reflective-transmitters made of other planar light guides, or Directly arrange optical devices such as reflective mirrors and reflective transmissive mirrors at opposite ends of the first planar optical waveguide 100 , as long as the solutions satisfying this structural design are within the protection scope of the present invention, details will not be repeated here.

Please refer to FIG. 2 and FIG. 3 together. In the embodiment of the present invention, the arrayed waveguide grating 30 can be obtained by etching or photolithography in the first planar optical waveguide 100. The arrayed waveguide grating 30 includes An input coupler 31 , an output coupler 32 , a first arrayed waveguide region 33 , a second arrayed waveguide region 34 and an output waveguide 35 . Wherein, the first arrayed waveguide area 33 and the second arrayed waveguide area 34 are located between the input coupler 31 and the output coupler 32, and the first arrayed waveguide area 33 includes at least two first waveguides 331, The second arrayed waveguide region 34 includes at least two second waveguides 341 . The two adjacent first waveguides 331 of the first waveguide array area 33 have a first optical path difference n ₁ *ΔL ₁ (assuming that the first arrayed waveguide area 33 arranges the adjacent first waveguide and the second waveguide in sequence and the third waveguide, if the length of the first waveguide is L, then the length of the second waveguide is L-ΔL ₁ , and the length of the third waveguide is L-2*ΔL ₁ ), where n ₁ is the The group refractive index of the first beam in the first waveguide 331 (because the first beam contains multiple wavelengths, due to the dispersion effect, the refractive index of the first beam in the first waveguide 331 needs to use the group refractive index express). Two second waveguides 341 adjacent to the second arrayed waveguide region 34 have a second optical path difference n ₂ *ΔL ₂ , where n ₂ is the group refractive index of the first light beam in the second waveguide, n ₁ may be equal to n ₂ or not. The first beam containing multiple wavelengths (or continuous wavelengths) is transmitted to the input coupler 31 , and the output coupler 32 outputs a second beam containing only one wavelength.

Specifically, for a conventional arrayed waveguide grating, it is assumed that the optical path difference of the multiple waveguides it includes is n*ΔL, where n _g is the group refractive index of the light beam in the waveguide, and ΔL is the If there is a difference in length, light beams containing multiple wavelengths are diffracted in the input coupler of the arrayed waveguide grating and coupled into each waveguide. Since the output ends of the plurality of waveguides are located on the circumference of the grating circle, the diffracted light generated when the light beam is diffracted in the input coupler reaches the output ends of the plurality of waveguides with the same phase. Since the adjacent waveguides maintain the same optical path difference n _g *ΔL, the diffracted light of the same wavelength has the same phase difference, while the diffracted light of different wavelengths has different phase differences. Therefore, the beams of different wavelengths are in the output coupler diffracted and focused to different locations. For conventional arrayed waveguide gratings, the free spectral range (Free Spectral Range, FSR) of its transmission spectrum can be expressed by the following formula (1):

where _λ0 is the free-space wavelength. It can be known from formula (1) that the FSR is determined by the length difference ΔL and the group refractive index _ng . The function of the arrayed waveguide grating is to demultiplex a light beam containing multiple wavelengths (or continuous wavelengths), so as to obtain multiple independent transmission peaks, or the arrayed waveguide grating can also be equivalent to a filter , only light beams satisfying specific diffraction conditions can pass through the arrayed waveguide grating, and the transmitted wavelengths are the wavelengths of multiple independent transmission peaks obtained, while other wavelengths will be filtered out.

In the embodiment of the present invention, the first optical path difference n ₁ *ΔL ₁ of the first arrayed waveguide region 33 is not equal to the second optical path difference n ₂ *ΔL ₂ of the second arrayed waveguide region 34 , so the arrayed waveguide grating 30 can be regarded as the cascade of two conventional arrayed waveguide gratings with an arrayed waveguide grating with an optical path difference of n ₁ *ΔL ₁ and an arrayed waveguide grating with an optical path difference of n ₂ *ΔL ₂ , or The stages of two equivalent filters regarded as a filter equivalent to an arrayed waveguide grating with an optical path difference of n ₁ *ΔL ₁ and a filter equivalent to an arrayed waveguide grating with an optical path difference of n ₂ *ΔL ₂ couplet. The first light beam passing through the arrayed waveguide grating 30 is equivalent to being filtered by these two equivalent filters at the same time, so the wavelength of the output second light beam is the transmission peak generated by the first arrayed waveguide region 33 and Among the transmission peaks generated by the second arrayed waveguide region 34 , the transmission peaks have overlapping wavelengths. Please refer to FIG. 4 and FIG. 5 together. FIG. 4 is a wavelength distribution diagram of the transmission peaks of a conventional arrayed waveguide grating with an optical path difference of n ₁ *ΔL ₁ and a conventional arrayed waveguide grating with an optical path difference of n ₂ *ΔL ₂ , It can be seen that the wavelengths of the transmission peaks under the arrayed waveguide grating with the optical path difference n ₁ *ΔL ₁ and the arrayed waveguide grating with the optical path difference n ₂ *ΔL ₂ coincide at a wavelength of 1.564 microns, therefore, the The wavelength of the second light beam output by the arrayed waveguide light beam 30 is 1.564 microns, as shown in FIG. 5 .

In the embodiment of the present invention, the arrayed waveguide grating 30 further includes a first electrode 37 and a second electrode 38, and the first electrode 37 and the second electrode 38 can be fixed on the first electrode 37 by evaporation or sputtering. On a planar optical waveguide 100, and the first electrode 37 is electrically connected to each first waveguide 331 in the first arrayed waveguide region 33, and the second electrode 38 is connected to the first waveguide region 34 in the second arrayed waveguide region 34. The respective second waveguides 341 are electrically connected. The first electrode 37 adjusts the refractive index of each first waveguide 331 of the first arrayed waveguide region 33 by applying a current or voltage, thereby adjusting the first optical path difference (the group refractive index is generally a function of the material refractive index , and related to the wavelength distribution of the first light beam); the second electrode 38 adjusts the refractive index of each second waveguide 341 in the second arrayed waveguide region 34 by applying a current or voltage, thereby adjusting the second Optical path difference. Since the arrayed waveguide grating 30 can produce different distributions of transmission peaks according to different first and second optical path differences, the overlapping transmission peaks also change accordingly, and the wavelength of the output second light beam also changes accordingly, The effect of adjusting the wavelength of the second light beam is realized. Wherein, the principle of modulating the refractive index of the first waveguide 331 and the second waveguide 341 by the first electrode 37 and the second electrode 38 includes but not limited to: thermo-optic effect, electro-optic effect, carrier-based The effect of changing the refractive index due to the change of the concentration of the carriers, the magneto-optic effect, the piezoelectric effect or the electro-absorption effect, etc., as long as the modulation method conforms to the design structure provided by the embodiment of the present invention is within the scope of protection of the present invention, it is not included here. Let me list them one by one.

It should be noted that, in other embodiments of the present invention, only the first electrode 37 or only the second electrode 38 may be provided, and these design solutions are within the protection scope of the present invention.

In the embodiment of the present invention, the gain medium 40 can be obtained by doping a working medium after etching or photolithography on the first planar optical waveguide 100, and the working medium can be erbium, praseodymium or other materials that can be used as The material of the working medium of the laser. The gain medium 40 is used to generate the oscillating first light beam and at the same time gain the second light beam. Specifically, an external pump source pumps the gain medium 40 (it can be optically pumped or electrically pumped), so that the gain medium 40 produces population inversion (that is, the number of particles on the high energy level is more than the number of particles on the low energy level), and emit the first light beam, the first light beam passes through the arrayed waveguide grating 30 to generate the second light beam, the second light beam propagates back and forth in the resonant cavity, and When passing through the gain medium 40, due to the stimulated radiation effect, the gain medium 40 generates laser light with the same wavelength and phase as the second light beam, thereby performing gain amplification on the second light beam to compensate for the various losses generated during the propagation of the second light beam in the resonant cavity. Therefore, the second light beam can continuously and stably propagate back and forth in the resonant cavity, and when the tunable laser 1000 works stably, the gain effect of the gain medium 40 is just equal to that of the second light beam in the The loss generated when propagating back and forth in the resonant cavity, wherein the loss includes the loss caused by the transmission of the second light beam through the reflective element 10 and the reflective transmission element 20, and the second light beam is caused by scattering and diffraction in the resonant cavity losses and other absorption losses.

In the embodiment of the present invention, the tunable laser 1000 further includes a phase modulator 50 , and the phase modulator 50 is disposed between the arrayed waveguide grating 30 and the reflection-transmission element 20 . The phase modulator 50 can change the first planar optical waveguide 100 or doping or manufacturing by evaporating or sputtering metal electrodes on the first planar optical waveguide 1000 and applying current or voltage on the metal electrodes. The refractive indices of other materials on the phase modulator 50 are obtained. The phase modulator 50 is used to keep the output optical power of the second light beam stable, such as fine-tuning to align the longitudinal mode in the laser cavity with the wavelength of the second light beam, so as to avoid power fluctuations.

Please refer to FIG. 6 together. It can be understood that in other embodiments of the present invention, the positions of the arrayed waveguide grating 30, the gain medium 40 and the phase modulator 50 can be arranged in various ways, such as The phase modulator 50 is disposed between the arrayed waveguide grating 30 and the gain medium 40, or the gain medium 40 is disposed between the arrayed waveguide grating 30 and the phase modulator 50, or the The arrayed waveguide grating 30 is disposed between the gain medium 40 and the phase modulator 50 in a manner that is not limited in the present invention.

Please refer to FIG. 7 together. FIG. 7 is a schematic diagram of a tunable laser 2000 provided in a second embodiment of the present invention, the tunable laser 2000 includes a reflection-transmission element 220, an arrayed waveguide grating 230, a gain medium 240 and a phase modulator 250 , the fabrication methods and functions of the reflection-transmission element 220, arrayed waveguide grating 230, gain medium 240, and phase modulator 250 are the same as those of the reflection-transmission element 20, arrayed waveguide grating 30, gain medium 40, modulation The manufacturing method and function of the phase device 50 are the same, and will not be repeated here.

The difference is that the gain medium 240 is fabricated separately in a second planar optical waveguide 2100, and the reflection-transmitting element 220, the arrayed waveguide grating 230 and the phase modulator 250 are fabricated in the first plane Optical waveguide 100. The second planar optical waveguide 2100 includes a first end face 241 and a second end face 242 opposite to the first end face 241, wherein the first end face 241 can be coated with an anti-reflection coating, and the second end face 242 can be coated with an anti-reflective coating. A reflective surface is formed to reflect the second light beam as a reflective element. Preferably, in order to obtain higher reflectivity, a reflective film may be coated on the reflective surface.

It should be noted that, in the embodiment of the present invention, a lens 260 may also be provided between the first planar light waveguide 100 and the second planar light waveguide 2100, and the lens 260 is used to collimate the incident light . Specifically, the second light beam transmitted by the gain medium 240 is collimated by the lens 260 and then transmitted to the arrayed waveguide grating 230, or the second light beam transmitted by the arrayed waveguide grating 230 is collimated by the lens 260 transmitted to the gain medium 240.

It should be noted that, in the embodiment of the present invention, the tunable laser 2000 may further include a functional unit 270, and the reflective transmission element 220 is arranged between the functional unit 270 and the phase modulator 250, and the The functional unit 270 includes, but is not limited to: a receiving unit, a modulating unit, or a filtering unit, to perform operations such as receiving, modulating, or filtering the output second light beam.

It should be noted that, in the embodiment of the present invention, the relative positions of the arrayed waveguide grating 230, the gain medium 240, and the phase modulator 250 can be exchanged, for example, the phase modulator 250 can be separately arranged on the second In the planar optical waveguide 2100, the gain medium 240 and the arrayed waveguide grating 230 are arranged in the first planar optical waveguide 100, or the arrayed waveguide grating 230, the gain medium 240, and the phase modulator 250 are all arranged in the same planar optical waveguide, and these structural design schemes are all within the protection scope of the present invention, and will not be repeated here.

Please also refer to FIG. 8 , which is a schematic diagram of a tunable laser 3000 according to a third embodiment of the present invention. The tunable laser 3000 includes a reflective element 310 , an arrayed waveguide grating 330 , a gain medium 340 and a phase modulator 350 . Wherein, the gain medium 340 is fabricated on a second planar optical waveguide 3100 , and the arrayed waveguide grating 330 and the phase modulator 350 are fabricated on the first planar optical waveguide 100 . The second planar optical waveguide 3100 includes a first end surface 341 and a second end surface 342, wherein the first end surface 341 can be coated with an anti-reflection film, and the second end surface 342 is formed into a smooth plane by cleavage, so as to As a reflective and transmissive element, the second light beam is output through the second end surface 342 .

It should be noted that, in the embodiment of the present invention, a lens 360 may also be provided between the first planar light waveguide 100 and the second planar light waveguide 3100, and the lens 360 is used to collimate the incident light . Specifically, the second light beam transmitted by the gain medium 340 is collimated by the lens 360 and then transmitted to the arrayed waveguide grating 330 , or the second light beam transmitted by the arrayed waveguide grating 330 is collimated by the lens 360 transmitted to the gain medium 340.

It should be noted that, in the embodiment of the present invention, the relative positions of the arrayed waveguide grating 330, the gain medium 340, and the phase modulator 350 can be exchanged, for example, the phase modulator 350 can be separately arranged on the second In the planar optical waveguide 3100, the gain medium 340 and the arrayed waveguide grating 330 are arranged in the first planar optical waveguide 100, or the arrayed waveguide grating 330, the gain medium 340, and the phase modulator 350 are all arranged in the same planar optical waveguide, and these structural design schemes are all within the protection scope of the present invention, and will not be repeated here.

Please refer to FIG. 9 together. FIG. 9 is a schematic diagram of a tunable laser 4000 according to a fourth embodiment of the present invention. The tunable laser 4000 includes a reflective element 410 , a reflective transmissive element 420 , an arrayed waveguide grating 430 , a gain medium 440 and a phase modulator 450 . Wherein, the reflective element 410 is obtained by cleaving the end face of the first planar optical waveguide 100 (or coating the reflective film after cleavage), and the arrayed waveguide grating 430 includes an input coupler 431 and a plurality of waveguides 436, One end of each waveguide 436 is coupled to the input coupler 431, and the other end is directly fabricated on the reflective element 410 (or the reflective element 410 can also be formed by integrating a waveguide reflector on each waveguide 436 In this case, the reflective element 410 can be formed by the waveguide reflective structure on the waveguide 436), the first light beam is distributed to each waveguide 436 through the input coupler 431, and the After being transmitted in the waveguide 436, it reaches the reflective element 410, and after being reflected by the reflective element 410, it reaches the input coupler 431 again, and outputs the second light beam, that is, the input coupler 431 simultaneously Played the role of the input coupler and output coupler.

Please refer to FIGS. 1 to 9 together. During operation, the gain medium 40 emits a first light beam containing multiple wavelengths (or continuous wavelengths) under the pumping of a pumping source. The first beam Diffraction to the first arrayed waveguide region 33 and the second arrayed waveguide region 34 of the arrayed waveguide grating 30 through the input coupler 31, the first waveguide 331 in the first arrayed waveguide region 33 has a first optical path difference n ₁ *ΔL ₁ , the second waveguide 341 in the second arrayed waveguide region 34 has a second optical path difference of n ₂ *ΔL ₂ , the output of the first arrayed waveguide region 33 is determined by the first optical path difference Multiple transmission peaks determined by n ₁ *ΔL ₁ , the second arrayed waveguide region 34 outputs multiple transmission peaks determined by the second optical path difference n ₂ *ΔL ₂ , so that the output waveguide 35 outputs the Among the multiple transmission peaks output by the first arrayed waveguide region 33 and the second arrayed waveguide region 34 , the wavelengths of the transmission peaks overlap, that is, the wavelength of the second light beam is the wavelength of the overlapped transmission peaks. The second light beam propagates back and forth in the resonant cavity formed by the reflective element 10 and the transmissive element 20 , and passes through the arrayed waveguide grating 30 , the gain medium 40 and the phase modulator 50 during the propagation. When the second light beam satisfies the amplitude condition and the phase condition in the resonant cavity at the same time, the second light beam can be stably transmitted in the resonant cavity and continuously output the output light. When the wavelength of the second light beam needs to be changed, the waveguides of the first arrayed waveguide region 33 can be changed only by applying the required voltage or voltage on the first electrode 37 and the second electrode 38. 331 and the refractive index of each waveguide 341 in the second arrayed waveguide region 34 is equivalent to adjusting the first optical path difference n ₁ *ΔL ₁ and the second optical path difference n ₂ *ΔL ₂ , thereby changing the The wavelength distribution of the transmission peak changes the wavelength of the second light beam, thereby realizing the effect of the adjustable wavelength of the second light beam.

It should be noted that each device in the embodiment of the present invention, such as the reflective element 10, the reflective-transmissive element 20, the arrayed waveguide grating 30, the gain medium 40 and the phase modulator 50 can be fabricated on the planar optical waveguide , can also be an independent optical device, and can also be partially fabricated on a planar optical waveguide, and partially adopt an independent optical device, and these solutions are all within the protection scope of the present invention.

In summary, the tunable laser 1000 provided by the embodiment of the present invention realizes the demultiplexing or filtering of the input first light beam by designing a waveguide array grating 30 including two length differences to output a The second light beam contains only one wavelength, and the wavelength of the second light beam can also be adjusted by evaporation or sputtering on the first electrode 37 and the second electrode 38 on the waveguide array grating 30, realizing continuous wavelength Adjustable effects. The tunable laser 1000 provided by the present invention can be integrally fabricated on a planar optical waveguide 100, so it has the advantages of high integration, small size, large wavelength adjustment range, and low requirements for process manufacturing, and satisfies large-capacity and high-speed optical transmission. And the use requirements of a new generation of optical devices.

The above description is a preferred embodiment of the present invention, and it should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications are also considered Be the protection scope of the present invention.

Claims (10)

1. An arrayed waveguide grating, comprising an input coupler, wherein the arrayed waveguide grating further comprises a first arrayed waveguide region and a second arrayed waveguide region, the first arrayed waveguide region comprising a plurality of first waveguides, And the adjacent first waveguides have a first optical path difference, the second arrayed waveguide region includes a plurality of second waveguides, and the adjacent second waveguides have a second optical path difference, wherein the The first optical path difference is not equal to the second optical path difference; Wherein, the arrayed waveguide grating further includes a first electrode, the first electrode is electrically connected to the plurality of first waveguides, and the first electrode is used to apply a voltage to the plurality of first waveguides to modulate The first optical path difference. 2. The arrayed waveguide grating according to claim 1, wherein the arrayed waveguide grating further comprises a second electrode, the second electrode is electrically connected to the plurality of second waveguides, and the second electrode It is used for applying voltage to the plurality of second waveguides to modulate the second optical path difference. 3. A tunable laser, comprising a reflective element, a reflection-transmissive element, and a gain medium, characterized in that it also includes the arrayed waveguide grating as claimed in any one of claims 1 to 2, the arrayed waveguide grating and the gain The medium is disposed between the reflection element and the reflection transmission element. 4. The tunable laser according to claim 3, wherein one end of the plurality of first waveguides and the plurality of second waveguides of the arrayed waveguide grating is arranged on the reflective element, and the other end is connected to the input Coupler coupling, the first light beam is distributed to the multiple first waveguides and multiple second waveguides for transmission through the input coupler, and is reflected by the reflective element to the input coupler to generate a second light beam , the input coupler outputs the second light beam. 5 . The tunable laser according to claim 4 , wherein the reflective element is composed of waveguide reflective structures integrated on the plurality of first waveguides and the plurality of second waveguides. 6. The tunable laser according to claim 3, wherein the arrayed waveguide grating further comprises an output coupler, one end of a plurality of first waveguides and a plurality of second waveguides of the arrayed waveguide grating is connected to the The output coupler is coupled, and the other end is coupled with the input coupler. 7. The tunable laser according to any one of claims 3 to 6, characterized in that, the tunable laser further comprises a phase modulator, and the phase modulator is arranged between the reflective element and the reflective transmissive element between. 8. The tunable laser according to claim 7, wherein the phase modulator covers the first planar optical waveguide with a metal electrode, and changes the first planar optical waveguide by applying a current on the metal electrode The refractive index obtained; or, The phase modulator covers the metal electrode on the first planar optical waveguide and applies current to the metal electrode to change the doping and the refractive index of the predetermined phase modulating material fabricated on the phase modulator And get. 9. The tunable laser according to claim 8, wherein the tunable laser further comprises a second planar optical waveguide, the gain medium and the reflective element are fabricated on the second planar optical waveguide, The arrayed waveguide grating, the phase modulator, and the reflection-transmission element are fabricated on the first planar optical waveguide; or, The gain medium and the reflective and transmissive elements are fabricated on the second planar optical waveguide, and the arrayed waveguide grating, phase modulator and reflective element are fabricated on the first planar optical waveguide. 10. The tunable laser according to claim 9, wherein a lens is arranged between the first planar optical waveguide and the second planar optical waveguide.