Single longitudinal mode transistor laser and system based on periodic current injection structure

Abstract

The application relates to a single-longitudinal-mode transistor laser based on a periodic current injection structure and a system, wherein the single-longitudinal-mode transistor laser based on the periodic current injection structure comprises a substrate, a first emitter, a lower cladding layer, a quantum well layer, an upper cladding layer, a base, a second emitter and a plurality of electrode contact layers; at least one of the plurality of electrode contact layers comprises a periodic gain-coupled electrode metal contact layer prepared through twice photolithography processes, and each layer is sequentially grown in a vertical direction through metal organic chemical vapor deposition; when the width of the periodic gain-coupled electrode metal contact layer is an integer multiple of half a wavelength, the single-longitudinal-mode transistor laser is enhanced in the resonant cavity to improve the laser mode selection. The single-longitudinal-mode transistor laser provided in the application does not need to be etched with a grating, so that no additional lattice loss is introduced, the mode selection function is realized under the condition of the lowest loss, and the single-longitudinal-mode performance of the device is improved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor lasers and proposes a single longitudinal mode transistor laser and a system based on a periodic current injection structure. Background Art

[0002] A transistor laser is a semiconductor laser device that achieves lasing by introducing a quantum well active region near the base of a double heterojunction transistor. Due to the reverse bias applied to the collector of the transistor laser, carriers with high recombination lifetimes are extracted from the quantum well within the base region, significantly reducing the equivalent carrier lifetime within the quantum well and significantly improving high-speed modulation characteristics. This technology has broad application prospects in the field of laser light sources for high-speed fiber-optic communications.

[0003] Most commonly used direct-modulation laser sources in commercial fiber-optic communications are diode lasers. They achieve signal transmission by applying a current modulation signal directly to the laser's two electrodes, thereby varying the light source's output power. While high-speed diode lasers have made significant progress in increasing modulation rates, the accumulation of carriers with high radiative recombination lifetimes within the quantum wells of diode lasers at high speeds leads to strong relaxation oscillations, limiting the direct modulation rate of single-tube diode lasers to below 50 Gb / s. Furthermore, relaxation oscillations reduce the ratio of modulation rate to modulation bandwidth.

[0004] Transistor lasers utilize a unique three-electrode structure to extract carriers with long radiative recombination lifetimes accumulated in quantum wells, reduce the relaxation caused by changes in photon concentration due to bias changes, and improve the response rate of the laser output power to modulated bias. This solves the relaxation oscillation problem caused by the accumulation of large amounts of carriers with long recombination lifetimes in quantum wells, thereby effectively improving the direct adjustment rate of the device. Existing reports have proven that a single-tube transistor laser can achieve 40Gb / s data transmission at a modulation bandwidth of 17GHz, with a rate-to-bandwidth ratio of 2.35, far greater than the 1.25 of ordinary diode lasers. This shows that transistor lasers are more likely to achieve high-speed data transmission.

[0005] However, due to the complex structure of transistor lasers and the poor performance of single longitudinal modes, it is necessary to select the longitudinal mode of transistor lasers. The most common mode selection scheme is to prepare a grating structure on the laser for mode selection. The existing method of preparing transistor laser gratings is to etch a periodic grating on a gold electrode (DOI:10.1063 / 1.3504608, DOI:10.1063 / 1.3453656). This structure is an electrode metal-air composite refractive index grating, which has two main disadvantages:

[0006] (1) Because the light distributed in the top electrode grating is small, the grating cannot be fully utilized for single longitudinal mode selection;

[0007] (2) The electrode contact layer is generally a heavily doped region, so the light field inside the metal electrode and the electrode contact layer will produce a large loss, reducing the light output power of the device.

[0008] Existing diode laser mode selection technology involves secondary epitaxial grating structures near the active region. This secondary epitaxy introduces new lattice losses, increasing the device's lasing threshold. Furthermore, in actual devices, the laser cavity length is not necessarily a strict integer multiple of a single grating width. This means that the grating in the period closest to the end facet is generally incomplete, introducing additional phase shifts. Therefore, the grating structure places high demands on the process.

[0009] Existing transistor laser grating technology involves directly photolithography of the top electrode contact layer, etching a metal / air structure with a refractive index surface metal grating, rather than a periodic electrode gain-coupled mode-selective structure. The disadvantages of this surface grating are poor light distribution within the electrode, poor mode-selective performance, and an increased device lasing threshold. Summary of the Invention

[0010] The purpose of this patent is to solve the problems of mode difference, large grating loss and low threshold in transistor lasers.

[0011] By adopting base periodic current injection into transistor lasers, introducing a periodic electrode structure near the base, and injecting periodic carrier distribution, the refractive index inside the active region is changed to achieve single longitudinal mode selection function. A single longitudinal mode transistor laser based on a periodic current injection structure is provided, including:

[0012] A periodic current injection gain-coupled electrode transistor laser comprises a substrate, a first emitter, a lower cladding layer, a quantum well layer, an upper cladding layer, a base, a second emitter, and a plurality of electrode contact layers, wherein the plurality of electrode contact layers comprise an emitter metal contact layer, a base metal contact layer, and a collector metal contact layer, at least one of the plurality of electrode contact layers comprises a periodic gain-coupled electrode metal contact layer formed by two photolithography processes, and each layer is sequentially grown in a vertical direction by metal organic chemical vapor deposition;

[0013] The substrate is provided at the bottom layer of the periodic current injection gain-coupled electrode transistor laser, and is used to support the epitaxial structure of the laser device and provide insulation or conductivity;

[0014] The first emitter and the second emitter are arranged and connected above or below the substrate to transmit emitter current;

[0015] The lower cladding layer is arranged above the substrate;

[0016] The quantum well layer is arranged above the lower cladding layer;

[0017] The upper cladding layer is arranged above the quantum well layer, wherein the quantum well layer is arranged between the lower cladding layer and the upper cladding layer, and the refractive index of the lower cladding layer and the upper cladding layer is lower than the refractive index of the quantum well layer, so as to confine the first part of the light field to the non-doped region of the lower cladding layer, the upper cladding layer and the quantum well layer, and the photons of the second part of the light field are absorbed by the doped region and the substrate, and the parts of the lower cladding layer and the upper cladding layer close to the quantum well layer are the main waveguide transmission light waves; wherein the proportion of the first part of the light field is much greater than the proportion of the second part of the light field;

[0018] The base is arranged above the substrate, and is used to transmit base current;

[0019] The collector is disposed above the substrate and is used to transmit collector current;

[0020] When the width of the metal contact layer of the periodic gain coupling electrode is an integer multiple of half the wavelength, the lasing ability of the single longitudinal mode transistor laser based on the periodic current injection structure in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0021] The present invention specifically provides: a single longitudinal mode transistor laser system based on a periodic current injection structure, comprising:

[0022] A periodic current injection gain-coupled electrode transistor laser comprises a substrate, a first emitter, a lower cladding layer, a quantum well layer, an upper cladding layer, a base, a second emitter, and a plurality of electrode contact layers, wherein the plurality of electrode contact layers comprise an emitter metal contact layer, a base metal contact layer, and a collector metal contact layer.

[0023] A first setting module is used to set at least one of the plurality of electrode contact layers to include a periodic gain-coupling electrode metal contact layer formed by two photolithography processes, wherein each layer is sequentially grown in a vertical direction by metal organic chemical vapor deposition;

[0024] A second setting module is used to set the substrate on the bottom layer of the periodic current injection gain-coupled electrode transistor laser, and the substrate is used to support the epitaxial structure of the laser device and provide insulation or conductivity;

[0025] a third setting module, configured to set and connect the first emitter and the second emitter above or below the substrate to transmit emitter current;

[0026] a fourth setting module, configured to set the lower cladding layer above the substrate;

[0027] a fifth setting module, configured to set the quantum well layer above the lower cladding layer;

[0028] a sixth setting module, configured to set the upper cladding layer above the quantum well layer, wherein the quantum well layer is set between the lower cladding layer and the upper cladding layer, and the refractive index of the lower cladding layer and the upper cladding layer is lower than the refractive index of the quantum well layer, so as to confine the first portion of the light field to the non-doped regions of the lower cladding layer, the upper cladding layer, and the quantum well layer, and the photons of the second portion of the light field are absorbed by the doped regions and the substrate, and the portions of the lower cladding layer and the upper cladding layer close to the quantum well layer serve as the main waveguide transmission light waves; wherein the proportion of the first portion of the light field is much greater than the proportion of the second portion of the light field;

[0029] a seventh setting module, configured to set the base electrode above the substrate, wherein the base electrode is configured to transmit a base current;

[0030] an eighth setting module, configured to set the collector above the substrate, wherein the collector is configured to transmit collector current;

[0031] When the width of the metal contact layer of the periodic gain coupling electrode is an integer multiple of half the wavelength, the lasing ability of the single longitudinal mode transistor laser system based on the periodic current injection structure in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0032] Compared with the prior art, the present invention can achieve the following beneficial effects: Specifically, the present invention provides a single longitudinal mode transistor laser and system based on a periodic current injection structure in the field of semiconductor technology, wherein the single longitudinal mode transistor laser based on the periodic current injection structure includes a substrate, a first emitter, a lower cladding layer, a quantum well layer, an upper cladding layer, a base, a second emitter, and multiple electrode contact layers; at least one of the multiple electrode contact layers includes a periodic gain coupling electrode metal contact layer formed by two photolithography processes, and each layer is grown sequentially in a vertical direction by metal organic chemical vapor deposition; when the width of the periodic gain coupling electrode metal contact layer is an integer multiple of half a wavelength, the laser mode selection of the single longitudinal mode transistor laser based on the periodic current injection structure is enhanced. The single longitudinal mode transistor laser based on the periodic current injection structure proposed in this application does not require etching of the grating, so it does not introduce additional lattice loss, so that the mode selection function is achieved with the lowest loss, thereby improving the single longitudinal mode performance of the device. In addition, the purpose of this patent is to solve the problems of mode difference, large grating loss, and low threshold in transistor lasers. By injecting periodic base current into the transistor laser, introducing a periodic electrode structure near the base, and injecting periodic carrier distribution, the refractive index inside the active region is changed to achieve the single longitudinal mode selection function. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of a gain-coupled electrode transistor laser based on base periodic current injection according to a second embodiment of the present invention;

[0034] Figure 2 A top view of a gain-coupled electrode transistor laser based on base periodic current injection according to a second embodiment of the present invention;

[0035] Figure 3 A front view of a gain-coupled electrode transistor laser based on base periodic current injection according to a second embodiment of the present invention;

[0036] Figure 4 A side view of a gain-coupled electrode transistor laser based on periodic base current injection according to a second embodiment of the present invention;

[0037] Figure 5 Schematic diagram of a gain-coupled electrode transistor laser based on collector periodic current injection according to embodiment 3 of the present invention;

[0038] Figure 6 A top view of a gain-coupled electrode transistor laser based on collector periodic current injection according to a third embodiment of the present invention;

[0039] Figure 7 A front view of a gain-coupled electrode transistor laser based on collector periodic current injection according to a third embodiment of the present invention;

[0040] Figure 8 A side view of a gain-coupled electrode transistor laser based on collector periodic current injection according to a third embodiment of the present invention;

[0041] Figure 9 Schematic diagram of a gain-coupled electrode transistor laser based on emitter periodic current injection according to a fourth embodiment of the present invention;

[0042] Figure 10 A top view of a gain-coupled electrode transistor laser based on emitter periodic current injection according to a fourth embodiment of the present invention;

[0043] Figure 11 A front view of a gain-coupled electrode transistor laser based on emitter periodic current injection according to a fourth embodiment of the present invention;

[0044] Figure 12 A side view of a gain-coupled electrode transistor laser based on emitter periodic current injection according to a fourth embodiment of the present invention;

[0045] Figure 13 Schematic diagram of a single-layer confinement layer transistor laser according to embodiment five of the present invention;

[0046] Figure 14 A top view of a single-layer confinement layer transistor laser is provided according to a fifth embodiment of the present invention;

[0047] Figure 15 A front view of a single-layer confinement layer transistor laser is provided according to a fifth embodiment of the present invention;

[0048] Figure 16 The figure is a side view of a single-layer confinement layer transistor laser according to the fifth embodiment of the present invention.

[0049] Reference numerals:

[0050] 100, 200, 300, 400-periodic current injection gain-coupled electrode transistor laser;

[0051] 101, 301, 701 - emitter electrode contact layer; 102, 702 - base periodic gain coupling electrode metal contact layer; 103, 503, 703 - collector electrode contact layer;

[0052] 302, 502-base electrode contact layer-base electrode contact layer;

[0053] 303 - collector stage periodic gain coupling electrode metal contact layer; 501 - emitter stage periodic gain coupling electrode metal contact layer;

[0054] 201, 401, 601, 801-substrate;

[0055] 202, 402, 602, 802-first emitter;

[0056] 203, 403, 603, 803-lower cladding;

[0057] 204, 404, 604, 804-quantum well layers;

[0058] 205, 405, 605, 805-upper cladding;

[0059] 206, 406, 606, 807 - base;

[0060] 207, 407, 607, 809 - second emitter;

[0061] 806 - limiting layer insulating window, 807 - limiting layer conductive region. DETAILED DESCRIPTION

[0062] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, identical modules are denoted by identical reference numerals. In the case of identical reference numerals, their names and functions are also identical. Therefore, their detailed description will not be repeated.

[0063] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation of the present invention.

[0064] Example 1

[0065] The present invention provides a single longitudinal mode transistor laser (hereinafter referred to as "single longitudinal mode transistor laser") based on a periodic current injection structure. The single longitudinal mode transistor laser includes a periodic current injection gain-coupled electrode transistor laser. The periodic current injection gain-coupled electrode transistor laser includes at least a substrate, a first emitter, a lower cladding layer, a quantum well layer, an upper cladding layer, a base, a second emitter, and multiple electrode contact layers. In accordance with the electrical characteristics of the electronic component BJT (bipolar junction transistor), the multiple electrode contact layers include an emitter (E) metal contact layer, a base (B) metal contact layer, and a collector (C) metal contact layer. BJTs generally include NPN and PNP structures, and current E = current B + current C. A periodic current injection gain-coupled electrode transistor laser is provided with multiple electrode contact layers, at least one of which includes a periodic gain-coupled electrode metal contact layer formed through two photolithography processes. Each layer is vertically grown sequentially by metal-organic chemical vapor deposition (MOCVD). In other words, each layer of material is grown layer by layer by MOCVD, and then two photolithography processes are used to etch the contact surfaces of the emitter (E), electrode contact layer, base (B), and periodic gain-coupled electrode contact layer. The emitter (E) and base (B) materials can serve as etch-stop layers. In the case of a PNP transistor laser, a P-side alloy is first grown, then the P-side alloy is photolithographed and etched to expose the base contact surface. Then, an N-side alloy is grown on the base, and the N-side alloy is further photolithographed to realize a periodic electrode.

[0066] A substrate is disposed at the bottom layer of a periodic current injection gain-coupled electrode transistor laser. The substrate supports the epitaxial structure of the laser device and provides insulation or conductivity. The first and second emitters of the periodic current injection gain-coupled electrode transistor laser are disposed and connected above or below the substrate. The first and second emitters are used to transmit emitter current. A lower cladding layer is disposed above the substrate. A quantum well layer is disposed above the lower cladding layer. An upper cladding layer is disposed above the quantum well layer. In other words, the quantum well layer is disposed between the lower and upper cladding layers. The refractive index of the lower and upper cladding layers is lower than that of the quantum well layer, thereby confining the first portion of the light field to the undoped regions of the lower, upper, and quantum well layers. Photons from the second portion of the light field are absorbed by the doped regions and the substrate. The portions of the lower and upper cladding layers near the quantum well layer serve as the primary waveguide for transmitting light waves. The proportion of the first portion of the light field is much greater than that of the second portion of the light field. In other words, by using materials with a lower refractive index than the quantum well layer, the upper and lower claddings confine the vast majority of the light field to the quantum well layer and the undoped regions of the upper and lower claddings, ensuring that photons are not absorbed by the doped regions and the high-loss substrate material. This requires that the portions of the upper and lower claddings closest to the quantum well layer be lightly doped or undoped. These lightly doped or undoped regions will serve as the primary waveguide for transmitting light waves. By gradually varying the composition of the materials in the upper and lower claddings, the band structure can be adjusted, providing additional potential energy for carriers, accelerating carrier transport within the cladding, and increasing the device's relaxation frequency and modulation bandwidth. Furthermore, this separated confinement heterostructure (SCH) can also limit the escape of carriers within the quantum well layer, enhancing the active region's ability to confine carriers.

[0067] The base is arranged above the substrate, and the base is used to transmit the base current. The collector is arranged above the substrate, and the collector is used to transmit the collector current. When the width of the metal contact layer of the periodic gain coupling electrode is an integer multiple of half the wavelength, the lasing ability of the single longitudinal mode transistor laser in the resonant cavity is enhanced, and the laser mode selection is completed. In other words, when the width of the periodic electrode = an integer multiple of half the wavelength, the mode selection of the lasing light is completed. The front and rear end faces are respectively coated with a high-reflection film and a high-transmittance film to enhance the lasing ability of the resonant cavity. The structure in this patent does not require the introduction of a grating structure, so it can avoid the additional loss and lattice mismatch introduced by the secondary epitaxy, so that a sufficiently low threshold can be maintained under the condition of single-mode lasing. Moreover, the structure will not have the end face phase shift problem in the grating structure, and the requirements for the end face process are reduced. Due to the reduction in process requirements, the yield of the device will be greatly improved, which is conducive to the development of the commercial potential of the device.

[0068] Example 2

[0069] Based on Example 1, please refer to Figures 1 to 4 , among which, in Figure 3 In the embodiment, the periodic current injection gain-coupled electrode transistor laser 100 includes a substrate 201, a first emitter 202, an emitter electrode contact layer 101, a lower cladding layer 203, a quantum well layer 204, an upper cladding layer 205, a base 206, a base periodic gain-coupled electrode metal contact layer 102, a second emitter 207, and a collector electrode contact layer 103. The periodic current injection gain-coupled electrode transistor laser 100 includes multiple electrode contact layers, at least one of which includes a base periodic gain-coupled electrode metal contact layer 102 formed through two photolithography processes, which are sequentially grown vertically by metal organic chemical vapor deposition to form a PNP transistor laser. In other words, the lower cladding layer 203 and the upper cladding layer 205 may be a combination of multiple different materials or layers with different doping. The substrate 201 is disposed at the bottom layer of the periodic current injection gain-coupled electrode transistor laser 100 and is used to support the epitaxial structure of the laser device and provide insulation or conductivity. Each layer grows sequentially along the Z-axis, and the functions of each layer of the device are as follows: the substrate 201 supports the epitaxial structure of the device and acts as an insulator or conductor. The grown epitaxial structure should match the internal lattice of the substrate 201. If strained material needs to be grown, it is necessary to ensure that the stress of the epitaxial strained material and the substrate 201 does not exceed the strain critical value of the material and can act as an insulator. The substrate 201 material does not need to be heavily doped to increase electrical performance.

[0070] A first emitter 202 is disposed and connected above or below the substrate 210. The first emitter 202 is used to transmit emitter current. An emitter electrode contact layer 101 is disposed and connected above the first emitter 202. A lower cladding layer 203 is disposed and connected above the first emitter 202. The emitter electrode contact layer 101 is disposed on both sides of the lower cladding layer 203. A quantum well layer 204 is disposed and connected to an upper cladding layer 205 above the lower cladding layer 203 and disposed above the quantum well layer 204. The quantum well layer 204 is disposed between the lower cladding layer 203 and the upper cladding layer 205. The refractive index of the lower cladding layer 203 and the upper cladding layer 205 is lower than the refractive index of the quantum well layer 204, so as to confine the first part of the light field in the single longitudinal mode transistor laser to the non-doped region of the lower cladding layer 203, the upper cladding layer 205 and the quantum well layer 205. The photons of the second part of the light field are absorbed by the doped region and the substrate 201. The part of the lower cladding layer 203 and the upper cladding layer 205 close to the quantum well layer 204 is the main waveguide transmission light wave. The proportion of the first part of the light field is much greater than that of the second part of the light field. In other words, the photons of the first part of the light field account for the vast majority, thereby improving the luminous efficiency.

[0071] The base 206 is arranged and connected above the upper cladding layer 205. The base 206 is used to transmit the base current. The base periodic gain coupling electrode metal contact layer 102 is arranged and connected above the base 206. The base 206 forms an ohmic contact with the base periodic gain coupling electrode contact layer 102. The second emitter 207 is arranged and connected above the base 206. The base periodic gain coupling electrode metal contact layer 102 is arranged on both sides of the second emitter 207. The collector electrode contact layer 103 is arranged and connected above the second emitter 207. When the width of the base periodic gain coupling electrode metal contact layer 102 is an integer multiple of half a wavelength, the laser emission capability of the single longitudinal mode transistor laser in the resonant cavity is enhanced to complete the laser mode selection. Compared with the existing method of preparing a grating on the gold electrode layer on the top of the transistor laser, the periodic refractive index region in this patent is closer to the active region and easier to adjust the light field mode. This patent provides a simple, low-threshold, highly single-mode semiconductor transistor laser for the field of high-speed optical fiber communication lasers.

[0072] Example 3

[0073] Based on Example 1, please refer to Figures 5 to 8 , among which, in Figure 7 In the embodiment, the periodic current injection gain-coupled electrode transistor laser 200 includes a collector-level periodic gain-coupled electrode metal contact layer 303, a substrate 401, a first emitter 402, an emitter electrode contact layer 301, a lower cladding layer 403, a quantum well layer 404, an upper cladding layer 405, a base 406, a second emitter 407, and a base electrode contact layer 302. The periodic current injection gain-coupled electrode transistor laser 200 includes multiple electrode contact layers, at least one of which includes a collector-level periodic gain-coupled electrode metal contact layer 303 formed through two photolithography processes. These layers are then grown vertically sequentially by metal-organic chemical vapor deposition to form a PNP transistor laser. The substrate 401 is disposed at the bottom layer of the periodic current injection gain-coupled electrode transistor laser 200. The substrate 401 supports the epitaxial structure of the laser device and provides insulation or conductivity. The first emitter 402 is disposed and connected above the substrate 401. The first emitter 402 is used to transmit the emitter current. The emitter electrode contact layer 301 is disposed and connected above the first emitter 402. The lower cladding layer 403 is disposed and connected above the first emitter 402. The emitter electrode contact layer 301 is disposed on both sides of the lower cladding layer 403. The quantum well layer 404 is disposed and connected above the lower cladding layer 403. The upper cladding layer 405 is disposed above the quantum well layer 404.

[0074] The quantum well layer 404 is disposed between the lower cladding layer 403 and the upper cladding layer 405. The refractive index of the lower cladding layer 403 and the upper cladding layer 405 is lower than that of the quantum well layer 404, thereby confining the first portion of the light field within the single longitudinal mode transistor laser to the undoped regions of the lower cladding layer 403, the upper cladding layer 405, and the quantum well layer 405. Photons from the second portion of the light field are absorbed by the doped regions and the substrate 401, and the portion of the lower cladding layer 403 and the upper cladding layer 405 near the quantum well layer 404 serves as the primary waveguide transmission light wave. The proportion of the first portion of the light field is much greater than that of the second portion of the light field. The base electrode contact layer 302 is disposed and connected above the base 406. The base electrode contact layer 302 is disposed on both sides of the second emitter 407. The collector-stage periodic gain coupling electrode metal contact layer 303 is disposed and connected above the second emitter 407. When the width of the collector-level periodic gain-coupling electrode metal contact layer 303 of the single longitudinal mode transistor laser 200 is an integer multiple of half the wavelength, the laser mode selection is completed in order to enhance the lasing ability of the single longitudinal mode transistor laser 200 in the resonant cavity. In order to maximize the ability to select a single longitudinal mode while ensuring low loss, this application uses a periodic electrode structure to inject carriers into the active region, so that the gain inside the active region changes periodically. The change in gain will change the imaginary part of the refractive index, resulting in a periodic change in the refractive index in the active region, forming a mode selection structure similar to a grating. The periodic electrode structure is a technology that uses gain coupling to control the imaginary part of the refractive index to achieve periodic refractive index distribution mode selection.

[0075] Example 4

[0076] Based on Example 1, please refer to Figures 9 to 12 , among which, in Figure 11In the figure, the periodic current injection gain-coupled electrode transistor laser 300 includes a substrate 601, a first emitter 602, an emitter-level periodic gain-coupling electrode metal contact layer 501, a lower cladding layer 603, a quantum well layer 604, an upper cladding layer 605, a base 606, a second emitter 607, a base electrode contact layer 502, and a collector electrode contact layer 503. The substrate 601 is disposed at the bottom layer of the periodic current injection gain-coupled electrode transistor laser 300. The first emitter 602 is disposed and connected above the substrate 601 and is used to transmit the emitter current. The emitter-level periodic gain-coupling electrode metal contact layer 501 is disposed and connected above the first emitter 602. The lower cladding layer 603 is disposed and connected above the first emitter 602. The emitter-level periodic gain-coupling electrode metal contact layer 501 is disposed on both sides of the lower cladding layer 603. The quantum well layer 604 is disposed and connected above the lower cladding layer 403. The upper cladding layer 605 is disposed above the quantum well layer 604. The quantum well layer 604 is disposed between the lower cladding layer 603 and the upper cladding layer 605. The base electrode 606 is disposed and connected above the upper cladding layer 605. The base electrode 606 is used to transmit the base current. The second emitter 607 is disposed and connected above the base electrode 606. The base electrode contact layer 502 is disposed and connected above the base electrode 606. The base electrode contact layer 502 is disposed on both sides of the second emitter 607. The collector electrode contact layer 503 is disposed and connected above the second emitter 607.

[0077] In the periodic current injection gain-coupled electrode transistor laser 300, multiple electrode contact layers are provided, at least one of which includes an emitter-stage periodic gain-coupled electrode metal contact layer 501 fabricated through two photolithography processes. These layers are sequentially grown vertically by metal organic chemical vapor deposition to form a PNP transistor laser. The substrate 601 supports the epitaxial structure of the laser device and provides insulation or conductivity. The refractive index of the lower cladding layer 603 and the upper cladding layer 605 is lower than that of the quantum well layer 604, thereby confining the first portion of the light field within the single longitudinal mode transistor laser to the undoped regions of the lower cladding layer 603, the upper cladding layer 605, and the quantum well layer 605. Photons from the second portion of the light field are absorbed by the doped regions and the substrate 601. The portion of the lower cladding layer 603 and the upper cladding layer 605 near the quantum well layer 604 serves as the primary waveguide transmission light wave, with the proportion of the first portion of the light field being much greater than that of the second portion of the light field. When the width of the metal contact layer 501 of the emitter-stage periodic gain coupling electrode is an integral multiple of half the wavelength, the lasing capability of the single longitudinal mode transistor laser in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0078] Furthermore, the present application can change the doping type of each electrode contact layer of the transistor laser according to the circuit design. For example, this patent is a PNP structure, in which the active region establishes a quantum well active region and a cladding between the N-type base and the P-type emitter. By regulating the injection of base electrons, the gain distribution in the active region is regulated. In fact, this gain coupling structure is also applicable to the NPN structure. For the NPN structure, only the injection electrodes of electrons and holes are changed in position, which does not have a significant impact on the gain coupling. Therefore, the gain coupling structure of the NPN structure should be the modified design of this patent.

[0079] Example 5

[0080] Based on Example 1, please refer to Figures 13 to 16 , among which, in Figure 15 The present invention proposes a periodic current injection gain-coupled electrode transistor laser 400, comprising a substrate 801, a first emitter 802, an emitter electrode contact layer 701, a base periodic gain-coupled electrode metal contact layer 702, a collector electrode contact layer 703, a lower cladding layer 803, a quantum well layer 804, an upper cladding layer 805, a confinement layer insulating window 806, a confinement layer conductive region 807, a base electrode 808, and a second emitter 809. Multiple electrode contact layers are provided in the periodic current injection gain-coupled electrode transistor laser 400, at least one of which includes a base periodic gain-coupled electrode metal contact layer 702 formed through two photolithography processes. Each layer is sequentially grown vertically by metal-organic chemical vapor deposition to form a PNP-type transistor laser. Substrate 801 is disposed at the bottom layer of the periodic current injection gain-coupled electrode transistor laser. Substrate 801 supports the epitaxial structure of the laser device and provides insulation or conductivity. A first emitter 802 is disposed and connected above the substrate 801. The first emitter 802 is used to transmit emitter current. An emitter electrode contact layer 701 is disposed and connected above the first emitter 802. A lower cladding layer 803 is disposed and connected above the first emitter 802. The emitter electrode contact layer 701 is disposed on both sides of the lower cladding layer 803. A quantum well layer 804 is disposed and connected above the lower cladding layer 803.

[0081] The upper cladding layer 805 is disposed above the quantum well layer 804. The quantum well layer 804 is disposed between the lower cladding layer 803 and the upper cladding layer 805. The refractive index of the lower cladding layer 803 and the upper cladding layer 805 is lower than that of the quantum well layer 804, so as to confine the first portion of the light field in the single longitudinal mode transistor laser to the undoped regions of the lower cladding layer 803, the upper cladding layer 805, and the quantum well layer 805. The photons of the second portion of the light field are absorbed by the doped regions and the substrate 801, and the portions of the lower cladding layer 803 and the upper cladding layer 805 near the quantum well layer 804 serve as the main waveguide transmission light waves. The proportion of the first portion of the light field is much greater than that of the second portion of the light field. The confinement layer conductive region 807 is disposed and connected above the upper cladding layer 805. A confinement layer insulating window 806 is disposed and connected above the upper cladding layer 805. The confinement layer insulating window 806 is disposed on both sides of the confinement layer conductive region 807, ensuring that carriers are transported only from within the conductive insulating window within the confinement layer conductive region 807, thereby limiting the location of the radiative recombination center and the light spot. A base electrode 808 is disposed and connected above the confinement layer insulating window 806 and the confinement layer conductive region 807. The base electrode 808 is used to transmit base current. A second emitter electrode 809 is disposed and connected above the base electrode 808. A base-level periodic gain-coupling electrode metal contact layer 702 is disposed and connected above the base electrode 808. The base-level periodic gain-coupling electrode metal contact layer 702 is disposed on both sides of the second emitter electrode 809. The collector electrode contact layer 703 of the periodic current injection gain-coupling electrode transistor laser 400 is disposed and connected above the second emitter electrode 809. When the width of the base-level periodic gain-coupling electrode metal contact layer 702 is an integral multiple of half the wavelength, the lasing capability of the single longitudinal mode transistor laser in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0082] In summary, the periodic grating structure used in the present application is a current injection window formed by etching, which does not require secondary epitaxy, has a simple process and a high yield rate. Since it is a gain-coupled structure, there is no need to consider the additional phase shift problem caused by the incomplete last period close to the end face faced in the grating structure. The unique three-electrode structure of the transistor laser makes it possible to prepare gain-coupled periodic electrode structures on all three electrodes. The advantage of the gain-coupling structure itself being easy to prepare ensures the yield of the device, and there is no need to consider the loss and lasing threshold increase caused by the grating structure. The different positions of the periodic gain-coupling structure only affect the different types of carriers, and have no essential effect on the composition of the gain-coupling structure. Taking a PNP-type transistor laser as an example, a periodic electrode is prepared at the base, and gain coupling is achieved by regulating the electrons injected from the base region into the active region. A periodic electrode is prepared at the emitter, and gain coupling is achieved by regulating the holes injected from the emitter region into the active region. A periodic electrode is prepared at the collector, and gain coupling is achieved by regulating the carriers drawn from the active region. In addition, Figure 13The single-layer confinement layer structure described in the specification can also add a second confinement layer to the lower waveguide to improve the confinement efficiency. For some materials that are difficult to side-oxidize, the side oxidation window can be replaced by an intrinsic semiconductor or other insulating material with low conductivity through multiple epitaxy, which also plays the role of limiting the splitting of the composite center. The reverse PN junction is a special case of multiple epitaxy. By using different types of doping to turn a low-conductivity material of the insulating window into a reverse-biased PN junction or directly epitaxially growing a heterogeneous PN junction as an insulating window, the confinement effect can be achieved. The present application adds a buried grating near the upper cladding layer, which can further narrow the line width on the basis of the gain coupling structure and in conjunction with the gain coupling effect brought by the periodic electrode, thereby improving the single longitudinal mode yield of the device. This patent proposes for the first time the implementation of a periodic gain-coupled electrode structure in a transistor laser, which effectively solves the problems of poor single-mode performance of transistor lasers and threshold increase after the introduction of a grating structure, and is an important driving force for the development of transistor lasers in the field of high-speed light sources.

[0083] Example 6

[0084] Based on the first embodiment, the present invention proposes a single longitudinal mode transistor laser system based on a periodic current injection structure, including:

[0085] A periodic current injection gain-coupled electrode transistor laser comprises a substrate, a first emitter, a lower cladding layer, a quantum well layer, an upper cladding layer, a base, a second emitter, and a plurality of electrode contact layers, wherein the plurality of electrode contact layers comprise an emitter (E) metal contact layer, a base (B) metal contact layer, and a collector (C) metal contact layer;

[0086] A first setting module is used to set at least one of the plurality of electrode contact layers to include a periodic gain-coupling electrode metal contact layer formed by two photolithography processes, wherein each layer is sequentially grown in a vertical direction by metal organic chemical vapor deposition;

[0087] A second setting module is used to set the substrate on the bottom layer of the periodic current injection gain-coupled electrode transistor laser, and the substrate is used to support the epitaxial structure of the laser device and provide insulation or conductivity;

[0088] a third setting module, configured to set and connect the first emitter and the second emitter above or below the substrate to transmit emitter current;

[0089] a fourth setting module, configured to set the lower cladding layer above the substrate;

[0090] a fifth setting module, configured to set the quantum well layer above the lower cladding layer;

[0091] a sixth setting module, configured to set the upper cladding layer above the quantum well layer, wherein the quantum well layer is set between the lower cladding layer and the upper cladding layer, and the refractive index of the lower cladding layer and the upper cladding layer is lower than the refractive index of the quantum well layer, so as to confine the first portion of the light field to the non-doped regions of the lower cladding layer, the upper cladding layer, and the quantum well layer, and the photons of the second portion of the light field are absorbed by the doped regions and the substrate, and the portions of the lower cladding layer and the upper cladding layer close to the quantum well layer serve as the main waveguide transmission light waves; wherein the proportion of the first portion of the light field is much greater than the proportion of the second portion of the light field;

[0092] a seventh setting module, configured to set the base electrode above the substrate, wherein the base electrode is configured to transmit a base current;

[0093] an eighth setting module, configured to set the collector above the substrate, wherein the collector is configured to transmit collector current;

[0094] When the width of the metal contact layer of the periodic gain coupling electrode is an integral multiple of half the wavelength, the lasing capability of the single longitudinal mode transistor laser system in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0095] Example 7

[0096] Based on the second embodiment, the single longitudinal mode transistor laser system includes (please refer to Figure 3 ):

[0097] The periodic current injection gain-coupled electrode transistor laser 100 includes a substrate 201, a first emitter 202, an emitter electrode contact layer 101, a lower cladding layer 203, a quantum well layer 204, an upper cladding layer 205, a base 206, a base-level periodic gain-coupled electrode metal contact layer 102, a second emitter 207, and a collector electrode contact layer 103;

[0098] a ninth setting module, configured to set at least one of the plurality of electrode contact layers to include a base-level periodic gain-coupling electrode metal contact layer 102 formed by two photolithography processes, and sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser;

[0099] a tenth setting module, configured to set the substrate 201 on the bottom layer of the periodic current injection gain-coupled electrode transistor laser 100, wherein the substrate is configured to support the epitaxial structure of the laser device and provide insulation or conductivity;

[0100] The eleventh setting module is used to set and connect the first emitter 202 above or below the substrate 210. The first emitter 202 is used to transmit the emitter current.

[0101] a twelfth setting module, configured to set and connect the emitter electrode contact layer 101 above the first emitter 202;

[0102] A thirteenth arrangement module is used to arrange and connect the lower cladding layer 203 above the first emitter 202 , wherein the emitter electrode contact layer 101 is arranged on both sides of the lower cladding layer 203 ;

[0103] A fourteenth setting module is used to set and connect the quantum well layer 204 above the lower cladding layer;

[0104] A fifteenth setting module is configured to set the upper cladding layer 205 above the quantum well layer 204, wherein the quantum well layer 204 is set between the lower cladding layer 203 and the upper cladding layer 205, and the refractive index of the lower cladding layer 203 and the upper cladding layer 205 is lower than the refractive index of the quantum well layer 204, so as to confine a first portion of the light field in the single longitudinal mode transistor laser system to the lower cladding layer 203, the upper cladding layer 205, and the non-doped region of the quantum well layer 205, and the photons of the second portion of the light field are absorbed by the doped region and the substrate 201, and the portion of the lower cladding layer 203 and the upper cladding layer 205 close to the quantum well layer 204 serves as the main waveguide transmission light wave; wherein the proportion of the first portion of the light field is much greater than the proportion of the second portion of the light field;

[0105] a sixteenth setting module, configured to set and connect the base electrode 206 above the upper cladding layer 205 , wherein the base electrode 206 is configured to transmit a base current;

[0106] a seventeenth setting module, configured to set and connect the base periodic gain coupling electrode metal contact layer 102 above the base 206 , wherein the base 206 forms an ohmic contact with the base periodic gain coupling electrode contact layer 102 ;

[0107] An eighteenth setting module is used to set and connect the second emitter 207 above the base 206, and the base-level periodic gain coupling electrode metal contact layer 102 is set on both sides of the second emitter 207;

[0108] A nineteenth setting module, configured to set and connect the collector electrode contact layer 103 above the second emitter 207;

[0109] When the width of the base-level periodic gain-coupling electrode metal contact layer 102 is an integral multiple of half the wavelength, the lasing capability of the single longitudinal mode transistor laser system in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0110] Example 8

[0111] Based on the third embodiment, the single longitudinal mode transistor laser system includes (please refer again to Figure 7 ):Periodic current injection gain-coupled electrode transistor laser 200, comprising:

[0112] Collector-level periodic gain-coupling electrode metal contact layer 303, substrate 401, first emitter 402, emitter electrode contact layer 301, lower cladding layer 403, quantum well layer 404, upper cladding layer 405, base 406, second emitter 407 and base electrode contact layer 302;

[0113] a twentieth setting module, configured to set at least one of the plurality of electrode contact layers to include a collector-level periodic gain-coupling electrode metal contact layer 303 formed by two photolithography processes, and sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser;

[0114] A twenty-first setting module is used to set the substrate 401 on the bottom layer of the periodic current injection gain-coupled electrode transistor laser 200, and the substrate 401 is used to support the epitaxial structure of the laser device and provide insulation or conductivity;

[0115] a twenty-second setting module, configured to set and connect the first emitter 402 above the substrate 401 , wherein the first emitter 402 is configured to transmit an emitter current;

[0116] a twenty-third setting module, configured to set and connect the emitter electrode contact layer 301 above the first emitter 402;

[0117] A twenty-fourth setting module is used to set and connect the lower cladding layer 403 above the first emitter 402, wherein the emitter electrode contact layer 301 is set on both sides of the lower cladding layer 403;

[0118] a twenty-fifth setting module, configured to set and connect the quantum well layer 404 above the lower cladding layer 403;

[0119] A twenty-sixth setting module is configured to set the upper cladding layer 405 above the quantum well layer 404, wherein the quantum well layer 404 is set between the lower cladding layer 403 and the upper cladding layer 405, and the refractive index of the lower cladding layer 403 and the upper cladding layer 405 is lower than the refractive index of the quantum well layer 404, so as to confine a first portion of the light field in the single longitudinal mode transistor laser system to the undoped region of the lower cladding layer 403, the upper cladding layer 405, and the quantum well layer 405, and photons of the second portion of the light field are absorbed by the doped region and the substrate 401, and the portion of the lower cladding layer 403 and the upper cladding layer 405 close to the quantum well layer 404 serves as the main waveguide transmission light wave; wherein the proportion of the first portion of the light field is much greater than the proportion of the second portion of the light field;

[0120] a twenty-seventh setting module, configured to set and connect the base electrode 406 above the upper cladding layer 405 , wherein the base electrode 406 is configured to transmit a base current;

[0121] a twenty-eighth setting module, configured to set and connect the second emitter 407 above the base 406;

[0122] a twenty-ninth setting module, configured to set and connect a base electrode contact layer 302 above the base electrode 406 , wherein the base electrode contact layer 302 is set on both sides of the second emitter electrode 407 ;

[0123] a 30th setting module, configured to set and connect the collector-stage periodic gain coupling electrode metal contact layer 303 above the second emitter 407;

[0124] When the width of the collector-stage periodic gain-coupling electrode metal contact layer 303 is an integral multiple of half the wavelength, the lasing capability of the single longitudinal mode transistor laser system in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0125] Example 9

[0126] Based on the fourth embodiment, the single longitudinal mode transistor laser system includes (please refer to Figure 11 ): A periodic current injection gain-coupled electrode transistor laser 300, comprising: a substrate 601, a first emitter 602, an emitter-level periodic gain-coupled electrode metal contact layer 501, a lower cladding layer 603, a quantum well layer 604, an upper cladding layer 605, a base 606, a second emitter 607, a base electrode contact layer 502, and a collector electrode contact layer 503;

[0127] a 30th setting module, configured to set at least one of the plurality of electrode contact layers to include an emitter-level periodic gain-coupling electrode metal contact layer 501 formed by two photolithography processes, and sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser;

[0128] A thirty-first setting module is used to set the substrate 601 on the bottom layer of the periodic current injection gain-coupled electrode transistor laser 300, and the substrate 601 is used to support the epitaxial structure of the laser device and provide insulation or conductivity;

[0129] a thirty-second setting module, configured to set and connect the first emitter 602 above the substrate 601 , wherein the first emitter 602 is configured to transmit an emitter current;

[0130] A thirty-third setting module is used to set and connect the emitter-stage periodic gain coupling electrode metal contact layer 501 above the first emitter 602;

[0131] A thirty-fourth setting module is used to set and connect the lower cladding layer 603 above the first emitter 602, wherein the emitter-stage periodic gain-coupling electrode metal contact layer 501 is set on both sides of the lower cladding layer 603;

[0132] A thirty-fifth setting module is used to set and connect the quantum well layer 604 above the lower cladding layer 403;

[0133] A thirty-sixth setting module is configured to set the upper cladding layer 605 above the quantum well layer 604, wherein the quantum well layer 604 is set between the lower cladding layer 603 and the upper cladding layer 605, and the refractive index of the lower cladding layer 603 and the upper cladding layer 605 is lower than the refractive index of the quantum well layer 604, so as to confine a first portion of the light field in the single longitudinal mode transistor laser system to the undoped region of the lower cladding layer 603, the upper cladding layer 605, and the quantum well layer 605, and photons of the second portion of the light field are absorbed by the doped region and the substrate 601, and the portion of the lower cladding layer 603 and the upper cladding layer 605 close to the quantum well layer 604 serves as the main waveguide transmission light wave; wherein the proportion of the first portion of the light field is much greater than the proportion of the second portion of the light field;

[0134] a thirty-seventh setting module, configured to set and connect the base electrode 606 above the upper cladding layer 605 , wherein the base electrode 606 is configured to transmit a base current;

[0135] a thirty-eighth setting module, configured to set and connect the second emitter 607 above the base 606;

[0136] a thirty-ninth setting module, configured to set and connect a base electrode contact layer 502 above the base electrode 606 , wherein the base electrode contact layer 502 is set on both sides of the second emitter electrode 607 ;

[0137] a 40th setting module, configured to set and connect the collector electrode contact layer 503 above the second emitter 607;

[0138] When the width of the emitter-stage periodic gain-coupling electrode metal contact layer 501 is an integral multiple of half the wavelength, the lasing capability of the single longitudinal mode transistor laser system in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0139] Example 10

[0140] Based on the fifth embodiment, the single longitudinal mode transistor laser system includes (please refer again to Figure 15 ): Periodic current injection gain-coupled electrode transistor laser 400, comprising:

[0141] A periodic current injection gain-coupled electrode transistor laser comprises a substrate 801, a first emitter 802, an emitter electrode contact layer 701, a base periodic gain-coupled electrode metal contact layer 702, a collector electrode contact layer 703, a lower cladding layer 803, a quantum well layer 804, an upper cladding layer 805, a confinement layer insulating window 806, a confinement layer conductive region 807, a base 808, and a second emitter 809;

[0142] a forty-first setting module, configured to set at least one of the plurality of electrode contact layers to include a base-level periodic gain-coupling electrode metal contact layer 702 formed by two photolithography processes, and sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser;

[0143] A forty-second setting module is used to set the substrate 801 on the bottom layer of the periodic current injection gain-coupled electrode transistor laser 400, and the substrate 801 is used to support the epitaxial structure of the laser device and provide insulation or conductivity;

[0144] a forty-third setting module, configured to set and connect the first emitter 802 above the substrate 801 , wherein the first emitter 802 is configured to transmit an emitter current;

[0145] A 44th setting module, configured to set and connect the emitter electrode contact layer 701 above the first emitter 802;

[0146] a 45th setting module, configured to set and connect the lower cladding layer 803 above the first emitter 802 , wherein the emitter electrode contact layer 701 is set on both sides of the lower cladding layer 803 ;

[0147] a 46th setting module, configured to set and connect the quantum well layer 804 above the lower cladding layer 803;

[0148] a forty-seventh setting module, configured to set the upper cladding layer 805 above the quantum well layer 804, wherein the quantum well layer 804 is set between the lower cladding layer 803 and the upper cladding layer 805, and the refractive index of the lower cladding layer 803 and the upper cladding layer 805 is lower than the refractive index of the quantum well layer 804, so as to confine a first portion of the light field in the single longitudinal mode transistor laser system to the undoped region of the lower cladding layer 803, the upper cladding layer 805, and the quantum well layer 805, and the photons of the second portion of the light field are absorbed by the doped region and the substrate 801, and the portion of the lower cladding layer 803 and the upper cladding layer 805 close to the quantum well layer 804 serves as the main waveguide transmission light wave; wherein the proportion of the first portion of the light field is much greater than the proportion of the second portion of the light field;

[0149] a 48th setting module, configured to set and connect the confinement layer conductive region 807 above the upper cladding layer 805;

[0150] a 49th setting module, configured to set and connect a confinement layer insulating window 806 above the upper cladding layer 805 , wherein the confinement layer insulating window 806 is disposed on both sides of the confinement layer conductive region 807 , thereby ensuring that carriers are transported only from the confinement layer conductive region 807 within the conductive insulating window, thereby limiting the location of the radiation recombination center and the light spot;

[0151] a fiftieth setting module, configured to set and connect the base electrode 808 above the restriction layer insulating window 806 and the restriction layer conductive region 807 , wherein the base electrode 808 is configured to transmit a base current;

[0152] a fifty-first setting module, configured to set and connect the second emitter 809 above the base 808;

[0153] a fifty-second setting module, configured to set and connect the base-level periodic gain-coupling electrode metal contact layer 702 above the base electrode 808 , wherein the base-level periodic gain-coupling electrode metal contact layer 702 is set on both sides of the second emitter electrode 809 ;

[0154] A fifty-third setting module is used to set and connect the collector electrode contact layer 703 above the second emitter 809;

[0155] When the width of the base-level periodic gain-coupling electrode metal contact layer 702 is an integral multiple of half the wavelength, the lasing capability of the single longitudinal mode transistor laser system in the resonant cavity is enhanced, thereby completing the laser mode selection.

[0156] It should be noted that those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the devices and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. In the several embodiments provided in the present application, the coupling between modules can be electrical, mechanical or other forms of coupling. In addition, the various functional modules in the various embodiments of the present application can be integrated into a processing module, or each module can exist physically alone, or two or more modules can be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules.

[0157] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0158] The above specific embodiments of the present invention do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A single longitudinal mode transistor laser based on a periodic current injection structure, characterized in that: include: A periodic current injection gain-coupled electrode transistor laser comprises a substrate, a first emitter, a lower cladding layer, a quantum well layer, an upper cladding layer, a base, a second emitter, and a plurality of electrode contact layers, wherein the plurality of electrode contact layers comprise an emitter electrode contact layer, a base metal contact layer, and a collector electrode contact layer, at least one of the plurality of electrode contact layers comprises a base-level periodic gain-coupled electrode metal contact layer formed by two photolithography steps, and is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser; The substrate is provided at the bottom layer of the periodic current injection gain-coupled electrode transistor laser, and is used to support the epitaxial structure of the laser device and provide insulation or conductivity; The first emitter is arranged and connected above the substrate, and the first emitter is used to transmit emitter current; The emitter electrode contact layer is arranged and connected above the first emitter; The lower cladding layer is arranged and connected above the first emitter, wherein the emitter electrode contact layer is arranged on both sides of the lower cladding layer; The quantum well layer is arranged and connected above the lower cladding layer; The upper cladding layer is arranged above the quantum well layer, wherein the quantum well layer is arranged between the lower cladding layer and the upper cladding layer, and the refractive index of the lower cladding layer and the upper cladding layer is lower than the refractive index of the quantum well layer, so as to confine the first part of the light field in the single longitudinal mode transistor laser based on the periodic current injection structure to the non-doped region of the lower cladding layer, the upper cladding layer and the quantum well layer, and the photons of the second part of the light field are absorbed by the doped region and the substrate, and the parts of the lower cladding layer and the upper cladding layer close to the quantum well layer serve as the main waveguide transmission light waves; wherein the proportion of the first part of the light field is much greater than the proportion of the second part of the light field; a confining layer conductive region, disposed and connected above the upper cladding layer; a confinement layer insulating window, disposed and connected above the upper cladding layer, the confinement layer insulating window being disposed on both sides of the conductive region of the confinement layer to ensure that carriers are transported only from the conductive region of the confinement layer within the conductive insulating window, thereby limiting the position of the radiation recombination center and the light spot; The base electrode is arranged and connected above the insulating window of the restriction layer and the conductive region of the restriction layer, and is used to transmit base current; The second emitter is arranged and connected above the base; The base-level periodic gain coupling electrode metal contact layer is arranged and connected above the base electrode, wherein the base-level periodic gain coupling electrode metal contact layer is arranged on both sides of the second emitter electrode; The collector electrode contact layer is arranged and connected above the second emitter; The collector is disposed above the substrate, and is used to transmit collector current; When the width of the base periodic gain coupling electrode metal contact layer is an integer multiple of half the wavelength, the lasing ability of the single longitudinal mode transistor laser based on the periodic current injection structure in the resonant cavity is enhanced, thereby completing the laser mode selection.

2. A single longitudinal mode transistor laser system based on a periodic current injection structure, characterized in that: include: A periodic current injection gain-coupled electrode transistor laser comprises a substrate, a first emitter, a lower cladding layer, a quantum well layer, an upper cladding layer, a base, a second emitter and a plurality of electrode contact layers, wherein the plurality of electrode contact layers comprises an emitter electrode contact layer, a base metal contact layer and a collector electrode contact layer; a forty-first setting module, configured to set at least one of the plurality of electrode contact layers to include a base periodic gain coupling electrode metal contact layer formed by two photolithography steps, and sequentially growing the metal contact layer in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser; a 42nd setting module, configured to set the substrate on the bottom layer of the periodic current injection gain-coupled electrode transistor laser, wherein the substrate is configured to support the epitaxial structure of the laser device and provide insulation or conductivity; a forty-third setting module, configured to set and connect the first emitter electrode above the substrate, wherein the first emitter electrode is configured to transmit an emitter current; a 44th setting module, configured to set and connect the emitter electrode contact layer above the first emitter; a 45th setting module, configured to set and connect the lower cladding layer above the first emitter, wherein the emitter electrode contact layer is set on both sides of the lower cladding layer; a forty-sixth arrangement module, configured to arrange and connect the quantum well layer above the lower cladding layer; a forty-seventh setting module, configured to set the upper cladding layer above the quantum well layer, wherein the quantum well layer is set between the lower cladding layer and the upper cladding layer, and the refractive index of the lower cladding layer and the upper cladding layer is lower than the refractive index of the quantum well layer, so as to confine a first portion of the light field in the single longitudinal mode transistor laser system based on the periodic current injection structure to the non-doped regions of the lower cladding layer, the upper cladding layer, and the quantum well layer, and photons of the second portion of the light field are absorbed by the doped regions and the substrate, and portions of the lower cladding layer and the upper cladding layer close to the quantum well layer serve as the main waveguide transmission light waves; wherein the proportion of the first portion of the light field is much greater than that of the second portion of the light field; a 48th setting module, configured to set and connect the conductive region of the confinement layer above the upper cladding layer; a forty-ninth setting module, configured to set and connect a confinement layer insulating window above the upper cladding layer, wherein the confinement layer insulating window is set on both sides of the conductive region of the confinement layer to ensure that carriers are transported only from the conductive region of the confinement layer within the conductive insulating window, thereby limiting the position of the radiation recombination center and the light spot; a fiftieth setting module, configured to set and connect the base electrode above the restriction layer insulating window and the restriction layer conductive region, the base electrode being configured to transmit a base current; a fifty-first setting module, configured to set and connect the second emitter electrode above the base electrode; a fifty-second setting module, configured to set and connect the base-level periodic gain coupling electrode metal contact layer above the base electrode, wherein the base-level periodic gain coupling electrode metal contact layer is set on both sides of the second emitter electrode; a fifty-third setting module, configured to set and connect the collector electrode contact layer above the second emitter; an eighth setting module, configured to set the collector electrode above the substrate, wherein the collector electrode is configured to transmit a collector current; When the width of the base-level periodic gain coupling electrode metal contact layer is an integer multiple of half the wavelength, the lasing ability of the single longitudinal mode transistor laser system based on the periodic current injection structure in the resonant cavity is enhanced, thereby completing the laser mode selection.

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