JP2006332137A - Light emitting element - Google Patents

Abstract

High light emission intensity is obtained with high efficiency by a light emitting element made of silicon.
A slot 121 is formed in a silicon thin wire core 102, and an active layer 122 is disposed inside the slot 121. The slot 121 is provided so as to extend in the extending direction of the silicon fine wire core 102 (light guiding direction), and is formed in a rectangular shape in plan view with a long side length L. For example, the width G of the widest portion of the slot 121 is formed to 0.05 μm, the width W of the silicon fine wire core 102 is formed to 0.41 μm, and the height H of the silicon fine wire core 102 is set to 0.3 μm. Is formed. The active layer 122 is made of silicon oxide to which ions of rare earth elements such as erbium are added (dispersed).
[Selection] Figure 1

Description

  The present invention relates to a light emitting device using a waveguide having silicon as a core.

  One of the major problems of current light-emitting elements for optical communication is cost reduction. Conventional light-emitting elements for optical communication mainly use direct transition type compound semiconductors. This type of light-emitting element is fabricated using a crystal growth technique and a microfabrication technique on the basis of a compound semiconductor substrate, but the substrate is about 3 inches in diameter even if it is large, and is limited to mass production. There is. In addition, crystal growth technology is essential, and the manufacturing cost per substrate is high.

  On the other hand, as a light emitting element using other than a compound semiconductor, there is an element using rare earth ions as a light emitting material. The core of the optical fiber is doped with Er ions, and excited by electromagnetic waves (light) with a wavelength of 0.98 μm to 1.48 μm, light emission in the vicinity of 1.55 μm, which is the communication wavelength band, can be obtained. However, in order to obtain a sufficient light output intensity as a light emitting element, it is necessary to lengthen the optical fiber to which rare earth ions are added to several tens of meters, so that the apparatus becomes large. For this reason, a technique using rare earth ions is widely used as an optical amplifier, but has not yet been put into practical use as a light emitting element.

  By the way, electronic devices such as a memory and an arithmetic unit are manufactured mainly based on silicon. The silicon substrate used to manufacture these silicon devices is large and has a diameter of 12 inches. In addition, it has advanced microfabrication technology and mass production technology compared to compound semiconductors, and is capable of mass-producing inexpensive devices. Is possible. Furthermore, silicon manufacturing apparatuses are widely used, and are still being developed at a rapid pace. For this reason, if a light emitting element made of silicon can be realized, the influence on this market is immeasurable. However, since silicon is an indirect transition type semiconductor, it is not easy to obtain light emission. Although there are attempts to manufacture a light emitting element using a silicon microstructure or the like, no device is mass-produced yet.

  Development of optical components other than light emitting elements using silicon has been actively performed (see Non-Patent Document 1). Since silicon has a large refractive index of about 3.5 with respect to electromagnetic waves in the vicinity of a wavelength of 1.55 μm, which is a communication wavelength band, when a dielectric channel waveguide having silicon as a core and silicon oxide as a cladding is formed, It is widely known that the core cross section is approximately 0.4 μm square or less with respect to the above wavelength. In this case, since the light intensity at the core portion is about 1000 times the light intensity of the optical fiber, high-efficiency light emission can be expected if a fluorescent material such as Er ions is dispersed in the core portion. It is done.

K. Yamada, et al., "Microphotonics devices Based on Silicon Wire Waveguiding System", IEICE TRANS. ELECTRON., Vol.E87-C, No.3, pp. 351-358, 2004.

 However, it has been found that Er ions in semiconductor crystals cannot be excited efficiently at room temperature. When amorphous silicon is used in place of silicon crystal, efficient excitation is possible. However, currently obtained amorphous silicon does not have a small light propagation loss, and as a result, efficient light-emitting devices have not been developed.

  The present invention has been made to solve the above problems, and an object of the present invention is to obtain a high emission intensity with high efficiency by a light emitting element made of silicon.

  The light emitting device according to the present invention includes a lower clad layer, a core made of silicon formed on the lower clad layer, a light incident end of a waveguide composed of the core, and a core part of the core. The waveguide includes at least a slot formed extending from the upper surface in the light guiding direction, an active layer formed inside the slot and including a light emitting material, and a light emitting end of the waveguide. The mode waveguide has a slot width of at most 0.1 μm. In the slot portion, the electric field strength is enhanced, and when excitation light is introduced into the active layer disposed in this region, light emission can be obtained from the light emitting material contained in the active layer. Note that the end of the slot may be tapered.

  The light emitting element includes a resonator disposed in the core region where the active layer is disposed, whereby laser oscillation can be obtained. The resonator may be composed of a first diffraction grating and a second diffraction grating formed in the core so as to sandwich the core region where the active layer is disposed. The first diffraction grating and the second diffraction grating may be formed on either of the side surfaces of the core and the upper surface of the core. In this case, the first slab silicon layer formed on the lower cladding layer connected to the core on which the first diffraction grating is formed, and the lower cladding layer connected to the core on which the second diffraction grating is formed. The second slab silicon layer formed on the first slab silicon layer, the first electrode connected to the first slab silicon layer, and the second electrode connected to the second slab silicon layer can modulate the oscillation wavelength. It becomes.

  In the above light emitting device, the resonator may be composed of a diffraction grating formed in a core region where the active layer is disposed. The diffraction grating should just be formed in either the both sides | surfaces of a core, and the upper surface of a core. In this case, an oscillation is provided by including a slab silicon layer formed on the lower cladding layer connected to the core on which the diffraction grating is formed, and a first electrode and a second electrode connected to the slab silicon layer. The wavelength to be modulated can be obtained. Further, the resonator may be composed of a ring resonator including a core in which an active layer is disposed.

  The light-emitting element may include a plurality of light-emitting elements formed on the lower clad layer and a channel core made of silicon disposed close to the plurality of light-emitting elements. In the case of a ring resonator, a plurality of light emitting elements formed on the lower cladding layer may be provided.

  As described above, according to the present invention, an active layer is disposed in a slot provided in a core made of silicon and having a width of 0.1 μm or less so that light emission can be obtained in a region where the electric field strength is enhanced. Therefore, the light emitting element made of silicon can obtain high emission intensity with high efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view (a), (a ′) and cross-sectional views (b), (c) schematically showing a configuration example of a light emitting element in an embodiment of the present invention. This light emitting device first includes a silicon thin wire core 102 made of, for example, single crystal silicon, and an upper cladding layer 103 disposed so as to cover the silicon thin wire core on a lower clad layer 101 made of silicon oxide. ing. The silicon thin wire core 102 may be made of polycrystalline silicon or amorphous silicon. Here, the surface of the silicon fine wire core 102 that is in contact with the plane formed on the surface of the lower clad layer 101 is the lower surface, and the surface of the silicon fine wire core 102 facing this is the upper surface, adjacent to these. A surface of the silicon fine wire core 102 substantially perpendicular to the plane is defined as a side surface.

  In addition, a spot size conversion core 104 and a spot size conversion core 105 made of, for example, silicon oxynitride are arranged at the input end and the output end of the silicon fine wire core 102. The spot size conversion core 104 includes light on the input side. The fiber 106 is optically connected, and the output side optical fiber 107 is optically connected to the spot size conversion core 105. Further, in the region of the spot size conversion core 104, the silicon fine wire core 102 has a tapered shape whose width becomes narrower toward the tip. Similarly, in the region of the spot size conversion core 105, the silicon fine wire core 102 has a tapered shape whose width becomes narrower toward the tip. Further, an upper clad layer 103 is also formed in the formation area of the spot size conversion core 104 and the spot size conversion core 105 so as to cover them (FIG. 1C).

  In addition, the spot size conversion core 104 and the spot size conversion core 105 have a height and a width that are about half of the cores of the optical fiber 106 and the optical fiber 107 to almost the same size. In the spot size conversion region configured as described above, “the refractive index of the silicon fine wire core 102> the refractive index of the spot size conversion core 104 and the spot size conversion core 105> the refractive index of the upper cladding layer 103”. . With the spot size conversion region configured as described above, the light guided through the optical fiber 106 is converted in spot size in a state where the loss is reduced, and is coupled to one end of the silicon fine wire core 102. Similarly, the light emitted from the silicon thin wire core 102 is converted in spot size in a state where loss is reduced, and is coupled to the optical fiber 107.

  In addition, in the light emitting device shown in FIG. 1, a slot 121 is formed in the silicon fine wire core 102, and an active layer 122 is disposed inside the slot 121. The slot 121 is provided so as to extend in the extending direction of the silicon fine wire core 102 (light guiding direction), and is formed in a rectangular shape in plan view with a long side length L. Further, as shown in FIG. 1B, the lower cladding layer 101 is formed so as to penetrate from the upper surface of the silicon fine wire core 102 to the bottom surface of the silicon fine wire core 102 in the normal direction (film thickness direction) of the plane of the lower cladding layer 101. . For example, the width G of the widest portion of the slot 121 is formed to 0.05 μm, the width W of the silicon fine wire core 102 is formed to 0.41 μm, and the height H of the silicon fine wire core 102 is set to 0.3 μm. Is formed. The active layer 122 is made of silicon oxide to which ions of rare earth elements such as erbium are added (dispersed). The active layer 122 is based on a material having a refractive index lower than that of the silicon fine wire core 102, and a light emitting material that emits light by excitation light such as ions of rare earth elements or fluorescent materials may be added thereto.

  According to the light emitting device configured as described above, first, in the region where the slot 121 of the silicon fine wire core 102 is provided, as shown in FIG. Compared with the increase. Therefore, according to the light emitting element shown in FIG. 1, the light intensity can be remarkably increased in the active layer 122 portion of the silicon fine wire core 102. Therefore, by emitting excitation light having a wavelength of 1.48 nm, for example, to the waveguide made of the silicon thin wire core 102, light emission having a wavelength of 1.54 μm that is a communication wavelength band can be efficiently obtained from the active layer 122. Become. In FIG. 2, the electric field strength in the cross-sectional direction (bb line direction in FIG. 1) of the silicon fine wire core 102 (waveguide) provided with the slot 121 is indicated by a solid line, and the electric field strength of the core (waveguide) without the slot. Is indicated by a wavy line.

Further, in the light emitting element shown in FIG. 1, the group refractive index in the silicon fine wire core 102 is different between the region where the slot 121 is formed and the region where the slot 121 is not present. For this reason, there is reflection at the boundary surface 131 and the boundary surface 132 at both ends of the slot 121, and a Fabry-Perot resonator having a length L is formed in the arrangement portion of the active layer 122 of the silicon fine wire core 102. . As a result, light emitted from the active layer 122 is amplified by the Fabry-Perot resonator and leads to laser oscillation (multimode oscillation). As shown in FIG. 3, when the width of the slot 121 exceeds 0.1 μm, the effect of increasing the electric field strength in this portion is hardly obtained. In FIG. 3, the value of the vertical axis (electric field strength ² ) of 1 indicates the value of a silicon fine wire core without a slot. Therefore, the width of the slot 121 may be at most 0.1 μm (0.1 μm or less).

  Here, since the cross-sectional dimension of the silicon fine wire core 102 is smaller than 1 μm, light having a wavelength of 4 μm or less propagates in a single mode in the waveguide constituted by the silicon fine wire core 102. In other words, the silicon thin wire core 102 only needs to be formed in such a dimension that a waveguide constituted by a clad made of silicon oxide has a single mode. For example, when the infrared light is set to a single mode, the cross-sectional dimension of the silicon fine wire core 102 may be about 0.3 to 0.4 μm in length and width.

  Note that the light-emitting element shown in FIG. 1 can be easily manufactured by using a commercially available SOI (Silicon on Insulator) substrate. For example, the silicon fine wire core 102 and the slot 121 can be formed by using the buried insulating layer of the SOI substrate as the lower cladding layer 101 and finely processing the SOI layer on the buried insulating layer. After the slot 121 is formed in this way, for example, after spin coating of SOG (Spin on Glass) to which erbium chloride is dispersed and added, an added film is formed, and then the slot 121 is finely processed. The active layer 122 can be formed in the inside. In addition, a silicon oxynitride film is formed thereon by, for example, a CVD (chemical vapor deposition) method, and the spot size conversion core 104 and the spot size conversion core 105 are formed by finely processing the film. It can be.

  Further, a silicon oxide film is formed thereon by, for example, a CVD method, and the upper cladding layer 103 can be formed by finely processing the film. Alternatively, the upper clad layer 103 may be formed by applying an organic resin having a desired refractive index and finely processing the coating film. In addition, as the fine processing described above, for example, a known electron beam lithography technique or photolithography technique and a known dry etching technique may be used. Alternatively, the pattern may be formed by nanoimprinting technology.

  Incidentally, for example, as shown in the plan view of FIG. 4, narrower detail 401 and detail 402 may be formed in the silicon fine wire core 102 at both ends of the active layer 122 (slot 121). In this way, a Fabry-Perot resonator including the reflecting surface 431 and the reflecting surface 432 having higher reflectivity can be configured, and a multimode oscillation laser can be obtained. In FIG. 4, a thin portion is formed by forming a concave portion on the side portion of the silicon fine wire core 102, but by forming a concave portion on the upper surface of the silicon fine wire core 102 as shown in FIG. 5. A thin portion may be formed. 5A is a plan view, and FIGS. 5B and 5C are cross-sectional views. In FIG. 5A, the lower clad layer 101 and the upper clad layer 103 are omitted. According to the configuration shown in FIG. 5, the detail 501 and the detail 502 are formed by the recess formed on the upper surface of the silicon fine wire core 102, and the reflection surface 531 and the reflection surface 532 having higher reflectivity are formed. .

  Further, as shown in the plan view of FIG. 6, Bragg mirrors 601 and Bragg mirrors 602 whose core diameters periodically change are formed in the silicon thin wire core 102 so as to sandwich the region of the active layer 122. Good. In FIG. 6, the Bragg mirror 601 and the Bragg mirror 602 are formed by forming irregularities (diffraction gratings) on the side surfaces of the silicon fine wire core 102. A resonator is constituted by the Bragg mirror 601 and the Bragg mirror 602 configured as described above, and according to the light-emitting element partially shown in FIG. 6, a single mode oscillation laser can be obtained. In FIG. 6, the lower clad layer, the upper clad layer, and the spot size conversion portion are omitted, but the other configurations are the same as those of the light emitting device shown in FIG.

  In addition, as shown in FIG. 7, a Bragg mirror 701 and a Bragg mirror 702 may be formed on the upper surface of the silicon fine wire core 102. 7A is a plan view, and FIGS. 7B and 7C are cross-sectional views. Further, in FIG. 7A, the lower cladding layer 101 and the upper cladding layer 103 are omitted. According to the configuration shown in FIG. 7, a resonator is configured by the Bragg mirror 701 and the Bragg mirror 702 formed on the upper surface of the silicon thin wire core 102. According to the light emitting element partially shown in FIG. The laser is obtained.

  Further, as shown in the plan view of FIG. 8, a Bragg mirror 801 whose core diameter periodically changes may be formed in a region where the active layer 122 of the silicon fine wire core 102 is formed. In FIG. 8, the Bragg mirror 801 is formed by forming irregularities (diffraction grating) on the side surface of the silicon fine wire core 102. A resonator is constituted by the Bragg mirror 801 configured as described above, and according to the light emitting element partially shown in FIG. 8, a single mode oscillation laser can be obtained. The Bragg mirror 801 is not limited to a uniform periodic structure, and may have a λ / 4 (λ is an oscillation wavelength) shift structure. By doing so, stable single mode oscillation can be obtained. In FIG. 8, the lower clad layer, the upper clad layer, and the spot size conversion portion are omitted, but the other configurations are the same as those of the light emitting device shown in FIG.

  Further, as shown in the plan view of FIG. 9, a Bragg mirror 901 whose slot width periodically changes may be formed in the slot 121. The Bragg mirror 901 configured as described above constitutes a resonator, and according to the light emitting element partially shown in FIG. 9, a single mode oscillation laser can be obtained. The Bragg mirror 901 is not limited to a uniform periodic structure, and may have a λ / 4 (λ is an oscillation wavelength) shift structure. By doing so, stable single mode oscillation can be obtained. In FIG. 9, the lower cladding layer, the upper cladding layer, and the spot size conversion portion are omitted, but the other configurations are the same as those of the light emitting device shown in FIG.

  Also, as shown in FIG. 10, a Bragg mirror 1001 may be formed on the upper surface of the silicon fine wire core 102 in the region where the active layer 122 is formed. 10A is a plan view, and FIGS. 10B and 10C are cross-sectional views. In FIG. 10A, the lower clad layer 101 and the upper clad layer 103 are omitted. According to the configuration shown in FIG. 10, a resonator is configured by the Bragg mirror 1001 formed on the upper surface of the silicon thin wire core 102, and according to the light emitting element partially shown in FIG. 10, a single mode oscillation laser is obtained. It is done. The Bragg mirror 1001 is not limited to a uniform periodic structure, and may have a λ / 4 (λ is an oscillation wavelength) shift structure. By doing so, stable single mode oscillation can be obtained.

  In the light-emitting element shown in FIG. 1, the boundary surface 131 and the boundary surface 132 at both ends are reflected due to the shape of the slot 121. However, as shown in the plan view of FIG. However, the active layer 1122 may be formed by the slot 1121 formed to be tapered. By tapering, the internal reflection of the guided light at the end of the slot 1121 is reduced. With this configuration, a resonator structure cannot be obtained and laser oscillation cannot be obtained, but light emission can be obtained from the active layer 122 by excitation light and function as a light emitting element.

  On the contrary, as shown in the plan view of FIG. 11B, the active layer 1122a is formed by a slot 1121a having a wider end than the center. Also good. With this configuration, the reflection intensity at the boundary surface 1131 and the boundary surface 1132 at both ends of the slot 1121a can be improved.

  Next, another light emitting element in the embodiment of the present invention will be described. FIG. 12 is a plan view schematically showing a partial configuration example of another light emitting element in the embodiment of the present invention. 12 includes a ring-shaped silicon fine wire core 1202, a silicon fine wire core 1211 coupled to the ring-shaped silicon fine wire core 1211, and a silicon fine wire core 1212 coupled to the directional coupler 1242. . A well-known ring resonator is constituted by the silicon thin wire core 1202. Further, in the light-emitting element partially shown in FIG. 12, a slot is formed in the silicon thin wire core 1202, and an active layer 1222 is disposed inside the slot. The slot extends in the extending direction of the silicon fine wire core 1202 (light guiding direction) and is provided in a ring shape.

  For example, the width G of the widest portion of the slot is formed to 0.05 μm, the width of the silicon fine wire core 1202 is formed to 0.41 μm, and the height of the silicon fine wire core 1202 is formed to 0.3 μm. Yes. The active layer 1222 is made of silicon oxide to which ions of rare earth elements such as erbium are added (dispersed). Although not shown, each core is covered with a clad layer to form a waveguide. According to the light emitting element configured as described above, when the excitation light is incident on the waveguide formed by the silicon fine wire core 1211, the incident excitation light is coupled to the silicon fine wire core 1202 by the directional coupler 1241. Thus, in the silicon thin wire core 1202, the erbium of the active layer 1222 is excited by the coupled excitation light, light emission is obtained from the active layer 1222, and the obtained light emission is amplified by the ring resonator, and multimode oscillation occurs. The oscillated laser light is guided by being coupled to a waveguide made of the silicon thin wire core 1212 by the directional coupler 1242 and output.

  Next, another light emitting element in the embodiment of the present invention will be described. FIG. 13 is a plan view (a) and a cross-sectional view (b) schematically showing a partial configuration example of another light emitting element in the embodiment of the present invention. A part of the light-emitting element shown in FIG. 13 has an oscillation wavelength changed by injecting carriers through an electrode 1308 and an electrode 1309. The light emitting device includes a silicon thin wire core 102 made of, for example, single crystal silicon on a lower clad layer 101 made of silicon oxide, and a slot 121 is formed in the silicon thin wire core 102. An active layer 122 is disposed inside. Also, a Bragg mirror portion 1301 and a Bragg mirror portion 1302 whose core diameters periodically change are formed in the silicon thin wire core 102 so as to sandwich the region of the active layer 122.

  In addition, the light-emitting element shown in FIG. 13 includes a slab silicon layer 102a connected to the silicon fine wire core 102 and formed thinner than the silicon fine wire core 102 in the formation region of the Bragg mirror portion 1301 and the Bragg mirror portion 1302. An electrode 1308 and an electrode 1309 are connected to the silicon layer 102a. The slab silicon layer 102a includes a portion connected to the silicon fine wire core 102 in the Bragg mirror portion 1301 formation region and a portion connected to the silicon fine wire core 102 in the Bragg mirror portion 1302 formation region. Further, these two portions are connected to each other by a slab silicon layer 102a separated from the silicon fine wire core 102.

  According to the light emitting device of FIG. 13 configured as described above, carriers are injected into the Bragg mirror unit 1301 and the Bragg mirror unit 1302 by the electrode 1308 and the electrode 1309 to which a voltage is applied, so that the Bragg mirror unit 1301 and the Bragg mirror unit 1302 are injected. The reflection characteristics in the mirror unit 1302 can be changed. In this way, by changing the reflection characteristics of the Bragg mirror unit 1301 and the Bragg mirror unit 1302 constituting the resonator, the oscillation wavelength can be changed according to the light emitting element of FIG. In addition, you may make the structure of each Bragg mirror part the same as the light emitting element shown in FIG.

  In the light-emitting element shown in FIG. 14, the oscillation wavelength can be changed by injecting carriers through the electrodes 1408 and 1409. FIG. 14 is a plan view (a) and a cross-sectional view (b) schematically showing a partial configuration example of another light emitting element in the embodiment of the present invention. 14 includes a silicon fine wire core 102 made of, for example, single crystal silicon on a lower clad layer 101 made of silicon oxide, and a slot 121 is formed in the silicon fine wire core 102. The active layer 122 is disposed inside the slot 121. In the region of the active layer 122, a Bragg mirror part 1401 whose core diameter periodically changes is formed in the silicon fine wire core 102.

  In addition, the light emitting device shown in FIG. 14 includes a slab silicon layer 102b that is connected to the silicon fine wire core 102 and formed thinner than the silicon fine wire core 102 in the formation region of the Bragg mirror portion 1401, and the slab silicon layer 102b includes An electrode 1408 and an electrode 1409 are connected. The electrodes 1408 and 1409 are arranged so as to sandwich the region of the active layer 122. According to the light emitting device of FIG. 14 configured in this manner, the reflection characteristics in the Bragg mirror unit 1401 are changed by injecting carriers into the Bragg mirror unit 1401 by the electrodes 1408 and 1409 to which a voltage is applied. Can do. As described above, by changing the reflection characteristics in the Bragg mirror 1401 constituting the resonator, the oscillation wavelength can be changed according to the light emitting element of FIG. The configuration of the Bragg mirror section may be the same as that of the light emitting element shown in FIGS.

  Next, another light emitting element in the embodiment of the present invention will be described. FIG. 15 is a plan view schematically showing a partial configuration example of another light emitting element in the embodiment of the present invention. FIG. 15 is a view in which the light emitting elements exemplified in FIG. 6 are integrated. In FIG. 15, a plurality of light emitting element portions 1501 are arranged close to a channel core 1510 made of silicon. Although not shown, each light emitting element 1501 and channel core 1510 are covered with a clad made of, for example, silicon dioxide.

  According to the integrated light emitting device configured in this way, each light emitting element portion 1501 in which the pumping light guided is arranged in the vicinity by guiding the pumping light to the waveguide formed by the channel core 1510. To emit light from the active layer 122 of each light emitting element portion 1501. As a result, laser oscillation can be obtained from each light emitting element portion 1501. The process from light emission to laser oscillation is the same as that of the light emitting element shown in FIG. 6, for example. By changing the reflection state of the Bragg mirror for each light emitting element portion 1501, laser light having a plurality of wavelengths oscillated in a single mode can be obtained.

  Next, another light emitting element in the embodiment of the present invention will be described. FIG. 16 is a plan view schematically showing a partial configuration example of another light emitting element in the embodiment of the present invention. FIG. 16 shows an integration of the light emitting elements exemplified in FIG. In FIG. 16, a plurality of light emitting element portions 1601 are optically coupled to a commonly provided silicon fine wire core 1611 by directional couplers 1641. In each light emitting element portion 1601, the silicon fine wire core 1612 is optically coupled by the directional coupler 1642. Each light emitting element portion 1601 is the same as the light emitting element shown in FIG. Although not shown, each light emitting element portion 1601, silicon fine wire core 1611, and silicon fine wire core 1612 are covered with a clad made of, for example, silicon dioxide.

  According to the integrated light emitting device configured as described above, the pumping light is guided through the waveguide made of the silicon fine wire core 1611 so that the guided pumping light is emitted through the directional coupler 1641. Light is obtained from the active layer 1222 of each light emitting element portion 1601 by being coupled to the element portion 1601. As a result, laser oscillation can be obtained from each light emitting element portion 1601. The process from light emission to laser oscillation is the same as that of the light emitting element shown in FIG. 12, for example.

  Although the case where erbium is used as the rare earth element has been described above, the present invention is not limited to this, and thulium (Tm), praseodymium (Pr), holmium (Ho), or the like may be used. For example, when thulium is used, the emission wavelength is 1.65 μm, and when holmium is used, the emission wavelength is 1.96 μm. Further, by adding these in combination, it becomes possible to widen the emission wavelength band. The active layer is not limited to silicon oxide to which these rare earth element ions are added (dispersed), but may be made of silicon oxynitride or silicon nitride to which the rare earth element ions are added. The active layer may be composed of an organic material such as an epoxy resin or a polyimide resin to which the rare earth element ions are added.

  By the way, the slot may penetrate the silicon fine wire core, and may be formed from the upper surface of the silicon fine wire core to the middle of the silicon fine wire core. Further, a slot can be provided even in a bent portion as long as light is guided in a single mode. Further, the slot need not be arranged at the center of the silicon fine wire core 102 in the planar direction of the lower cladding layer 101. However, the effect of increasing the electric field strength can be obtained most by arranging the slot at the approximate center of the silicon fine wire core 102. In the above description, the excitation light is guided to the silicon thin wire core on which the active layer is formed, so that the active layer is irradiated with the excitation light. A window through which the core is exposed may be provided, and the excitation light may be irradiated from here.

FIG. 2 is a plan view (a), (a ′) and cross-sectional views (b), (c) schematically showing a configuration example of a light emitting element in an embodiment of the present invention. It is a distribution map which shows distribution of the electric field strength of the cross-sectional direction in the silicon | silicone thin wire | line core 102 in which the slot 121 was formed. It is a characteristic view which shows the relationship between the width | variety of a slot, and an electric field strength. It is a top view which shows typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is the top view (a), sectional drawing (b), (c) which shows the example of a partial structure of the other light emitting element in embodiment of this invention typically. It is a top view which shows typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is the top view (a), sectional drawing (b), (c) which shows the example of a partial structure of the other light emitting element in embodiment of this invention typically. It is a top view which shows typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is a top view which shows typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is the top view (a), sectional drawing (b), (c) which shows the example of a partial structure of the other light emitting element in embodiment of this invention typically. It is a top view which shows typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is a top view which shows typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is the top view (a) and sectional drawing (b) which show typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is the top view (a) and sectional drawing (b) which show typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is a top view which shows typically the example of a partial structure of the other light emitting element in embodiment of this invention. It is a top view which shows typically the example of a partial structure of the other light emitting element in embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Lower clad layer, 102 ... Silicon fine wire core, 103 ... Upper clad layer, 104, 105 ... Spot size conversion core, 106, 107 ... Optical fiber, 121 ... Slot, 122 ... Active layer, 131, 132 ... Interface.

Claims (12)

A lower cladding layer;
A core made of silicon formed on the lower cladding layer;
A light incident end of a waveguide composed of the core;
A slot formed in a part of the core so as to extend from the upper surface of the core in a light guiding direction;
An active layer formed inside the slot and including a light emitting material;
And at least a light exit end of the waveguide,
The waveguide is a single mode waveguide,
The slot has a width of at most 0.1 μm. The light emitting device according to claim 1.
A light emitting device comprising: a resonator disposed in a region of the core where the active layer is disposed. The light emitting device according to claim 2, wherein
The light emitting device according to claim 1, wherein the resonator includes a first diffraction grating and a second diffraction grating formed in the core so as to sandwich the core region where the active layer is disposed. The light emitting device according to claim 2, wherein
The light emitting element, wherein the resonator is configured by a diffraction grating formed in a region of the core where the active layer is disposed. The light emitting device according to claim 2, wherein
The light emitting device according to claim 1, wherein the resonator includes a ring resonator including the core on which the active layer is disposed. The light emitting device according to claim 1.
The light emitting element, wherein an end of the slot is tapered. The light emitting device according to claim 3.
The first diffraction grating and the second diffraction grating are formed on one of both side surfaces of the core and the upper surface of the core. The light emitting device according to claim 4.
The diffraction grating is formed on one of both side surfaces of the core and the upper surface of the core. The light emitting device according to claim 3 or 7,
A first slab silicon layer formed on the lower cladding layer connected to the core on which the first diffraction grating is formed;
A second slab silicon layer formed on the lower cladding layer connected to the core on which the second diffraction grating is formed;
A first electrode connected to the first slab silicon layer;
And a second electrode connected to the second slab silicon layer. The light emitting device according to claim 4 or 8,
A slab silicon layer formed on the lower cladding layer connected to the core on which the diffraction grating is formed;
A light emitting device comprising: a first electrode and a second electrode connected to the slab silicon layer. The light emitting device according to any one of claims 3, 4, 7, and 8.
A plurality of the light emitting elements formed on the lower cladding layer;
And a channel core made of silicon arranged close to the plurality of light emitting elements. The light emitting device according to claim 5, wherein
A light emitting device comprising a plurality of the light emitting devices formed on the lower cladding layer.

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