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

Abstract

The invention relates to the technical field of semiconductors, in particular to a single longitudinal mode transistor laser based on a periodic current injection structure and a system. The single longitudinal mode transistor laser based on the periodic current injection structure comprises a substrate, a first emitter, a lower cladding, a quantum well layer, an upper cladding, 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 coupling electrode metal contact layer through two photoetching processes, and all the layers are sequentially grown in the vertical direction through metal organic chemical vapor deposition; when the width of the periodic gain coupling electrode metal contact layer is an integral multiple of the half wavelength, the lasing capability of the single longitudinal mode transistor laser in the resonant cavity is enhanced, and laser mode selection is completed. According to the single longitudinal mode transistor laser provided by the invention, grating etching is not needed, so that additional lattice loss is not introduced, a mode selection function is realized under the condition of lowest loss, and the single longitudinal mode performance of a device is improved.

Description

Technical Field

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

[0002] Transistor laser is a semiconductor laser device that realizes lasing by introducing a quantum well active region near the base region of a double heterojunction transistor. Due to the reverse bias of the collector of the transistor laser, the carriers with high recombination lifetime in the quantum well inside the base region will be extracted, so the equivalent carrier lifetime in the quantum well will be greatly reduced, and the high-speed modulation characteristics will be greatly improved. It has broad application prospects in the field of laser light sources for high-speed optical fiber communications.

[0003] The commonly used direct modulated laser light sources in commercial optical fiber communications are mostly diode lasers, which achieve signal transmission by directly applying a current modulation signal to the two electrodes of the laser and changing the output power of the light source. Although high-speed diode lasers have made great progress in improving the modulation rate, due to the serious accumulation of high-radiation recombination lifetime carriers in the quantum well of the diode laser under high-speed operation, strong relaxation oscillations will be generated, limiting the direct modulation rate of a single-tube diode laser to below 50Gb / s, and relaxation oscillations will reduce the ratio of modulation rate to modulation bandwidth.

[0004] Transistor lasers use a unique three-electrode structure to extract carriers with long radiation recombination lifetimes accumulated in quantum wells, reduce the relaxation of photon concentration changes caused by bias changes, increase the response rate of laser output power to modulated bias, and solve the relaxation oscillation problem caused by the accumulation of large amounts of carriers with long recombination lifetimes in quantum wells. Therefore, the direct adjustment rate of the device can be effectively improved. Existing reports have proven that single-tube transistor lasers can achieve 40Gb / s data transmission at a modulation bandwidth of 17GHz, and the ratio of rate to bandwidth has increased to 2.35, which is much larger 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 mode, the longitudinal mode of transistor lasers must be selected. The most commonly used 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 less light is distributed in the top electrode grating, 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] The existing diode laser mode selection technology is to use a secondary epitaxial grating structure near the active region. The secondary epitaxy will introduce new lattice losses and increase the device lasing threshold. Moreover, in actual devices, the cavity length of the laser is not necessarily strictly an integer multiple of the width of a single grating, which means that the grating in the period closest to the end face is generally incomplete, which will introduce additional phase shifts. Therefore, the grating structure has very high requirements for the process.

[0009] The existing transistor laser grating technology is to directly photolithography the top electrode contact layer to etch out the refractive index surface metal grating of the metal / air structure, rather than the gain-coupled mode-selective structure of the periodic electrode. The disadvantages of this surface grating are that the light distribution inside the electrode is small, the mode-selective performance is poor, and it will increase the 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 a base periodic current injection transistor laser, introducing a periodic electrode structure near the base, and injecting carrier periodic distribution, changing the refractive index inside the active region, a single longitudinal mode selection function is achieved, and 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 arranged at the bottom 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 conduction;

[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 disposed 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 disposed above the substrate, and the base is used to transmit a 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 integral 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 to complete 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 comprises 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 at the bottom 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 conduction;

[0025] A third setting module, used for setting and connecting the first emitter and the second emitter above or below the substrate, so as to transmit the emitter current;

[0026] A fourth setting module, used for setting the lower cladding layer above the substrate;

[0027] A fifth setting module, used for setting the quantum well layer above the lower cladding layer;

[0028] A sixth setting module is used 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 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;

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

[0030] an eighth setting module, used to set the collector above the substrate, the collector being used to transmit collector current;

[0031] When the width of the metal contact layer of the periodic gain coupling electrode is an integral 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 to complete 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, a quantum well layer, an upper cladding, a base, a second emitter and a plurality of electrode contact layers; at least one of the plurality of electrode contact layers includes a periodic gain coupling electrode metal contact layer through two photolithography processes, and each layer is sequentially grown 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 is completed by enhancing the lasing ability of the single longitudinal mode transistor laser based on the periodic current injection structure in the resonant cavity. The single longitudinal mode transistor laser based on the periodic current injection structure proposed in the present application does not need to etch the grating, so it will not introduce additional lattice loss, so that the mode selection function is realized under the condition of minimum loss, and the single longitudinal mode performance of the device is improved. 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 using base periodic current injection into the transistor laser, a periodic electrode structure is introduced near the base, and the refractive index inside the active region is changed by injecting periodic carrier distribution to achieve the single longitudinal mode selection function. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A 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 is provided according to the 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 base periodic current injection according to a second embodiment of the present invention;

[0037] Figure 5 A 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 is provided 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] Fig. 9 A 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] Fig.10 A top view of a gain-coupled electrode transistor laser based on emitter periodic current injection is provided according to a fourth embodiment of the present invention;

[0043] Fig.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] Fig.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] Fig.13 A schematic diagram of a single-layer confinement layer transistor laser is provided according to Embodiment 5 of the present invention;

[0046] Fig.14 A top view of a single-layer confinement layer transistor laser is provided according to Embodiment 5 of the present invention;

[0047] Fig.15 A front view of a single-layer confinement layer transistor laser is provided according to Embodiment 5 of the present invention;

[0048] Fig.16 The figure is a side view of a single-layer confinement layer transistor laser provided 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 layer;

[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, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0063] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is 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] Embodiment 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, wherein 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 at least includes 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. According to the electrical characteristics of the electronic component BJT (bipolar junction transistor), the plurality of electrode contact layers include an emitter (E) metal contact layer, a base (B) metal contact layer, and a collector (C) metal contact layer. The BJT generally includes NPN and PNP structures, and the current E = current B + current C. In a periodic current injection gain-coupled electrode transistor laser, at least one of the multiple electrode contact layers includes a periodic gain-coupled electrode metal contact layer that has been processed by two photolithography processes, and each layer is sequentially grown in a vertical direction by metal-organic chemical vapor deposition (MOCVD (Metal-organic Chemical Vapor Deposition). In other words, each layer of material is grown layer by layer by MOCVD, and the emitter (E), electrode contact layer, base (B) and contact surfaces of the periodic gain-coupled electrode contact layer are etched out respectively by two photolithography processes, and the materials of the emitter (E) and base (B) can be used as an etching stop layer. If it is a PNP type transistor laser, a P-face alloy is grown first, and then the P-face alloy is photolithographed and etched to expose the base contact surface, and then an N-face alloy is grown on the base, and the N-face alloy is further photolithographed to realize a periodic electrode.

[0066] The substrate is arranged at the bottom 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. The first emitter and the second emitter of the periodic current injection gain-coupled electrode transistor laser are arranged and connected above or below the substrate, and the first emitter and the second emitter are used to transmit the emitter current. The lower cladding is arranged above the substrate. The quantum well layer is arranged above the lower cladding. The upper cladding is arranged above the quantum well layer. In other words, the quantum well layer is arranged between the lower cladding and the upper cladding. The refractive index of the lower cladding and the upper cladding 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 area of ​​the lower cladding, the upper cladding and the quantum well layer, and the photons of the second part of the light field are absorbed by the doped area and the substrate, and the parts of the lower cladding and the upper cladding close to the quantum well layer are the main waveguide transmission light waves. The proportion of the first part of the light field is much greater than the proportion of the second part of the light field. In other words, the upper and lower claddings use materials with a lower refractive index than the quantum well layer to confine most of the light field to the quantum well layer and the non-doped regions of the upper and lower claddings, ensuring that photons will not be absorbed by the doped regions and high-loss substrate materials. This requires that the parts of the upper and lower claddings closest to the quantum well layer should be lightly doped or undoped, and these lightly doped or undoped parts will serve as the main waveguides to transmit light waves. The upper and lower claddings can adjust the band structure through gradual changes in the composition of the materials, provide additional potential energy for carriers, accelerate the transport of carriers inside the cladding, and increase the relaxation frequency and modulation bandwidth of the device. In addition, this separated confinement heterostructure (SCH) can also limit the escape of carriers in the quantum well layer and improve the ability of the active region to limit 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 laser mode selection is completed to enhance the lasing ability of the single longitudinal mode transistor laser in the resonant cavity. 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 need to introduce a grating structure, so it can avoid the additional loss and lattice mismatch introduced by the secondary epitaxy, so it can maintain a sufficiently low threshold 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 commercialization potential of the device.

[0068] Embodiment 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 is provided with at least one of the plurality of electrode contact layers including a base periodic gain-coupled electrode metal contact layer 102 that has been subjected to two photolithography processes, and is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP type transistor laser. In other words, the lower cladding layer 203 and the upper cladding layer 205 here may be a combination of layers of multiple different materials or different doping. The substrate 201 is provided at the bottom layer of the periodic current injection gain-coupled electrode transistor laser 100, and the substrate 201 is used to support the epitaxial structure of the laser device and provide insulation or conductive functions. Each layer grows along the Z axis in sequence, 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] The first emitter 202 is arranged and connected above or below the substrate 210, and the first emitter 202 is used to transmit the emitter current. The emitter electrode contact layer 101 is arranged and connected above the first emitter 202. The lower cladding layer 203 is arranged and connected above the first emitter 202, and the emitter electrode contact layer 101 is arranged on both sides of the lower cladding layer 203. The quantum well layer 204 is arranged and connected to the upper cladding layer 205 above the lower cladding layer 203, and is arranged above the quantum well layer 204. The quantum well layer 204 is arranged between the lower cladding layer 203 and the upper cladding layer 205. The refractive index of the lower cladding 203 and the upper cladding 205 is lower than that 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 203, the upper cladding 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 203 and the upper cladding 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, and 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, and 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, and 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 lasing ability of the single longitudinal mode transistor laser in the resonant cavity is enhanced to complete the laser mode selection. Compared with the existing preparation of the 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 it is easier to adjust the light field mode. This patent provides a simple, low-threshold, high single-mode semiconductor transistor laser for the field of lasers for high-speed optical fiber communications.

[0072] Embodiment 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. In the periodic current injection gain-coupled electrode transistor laser 200, at least one of the multiple electrode contact layers includes a collector-level periodic gain-coupled electrode metal contact layer 303 that has been subjected to two photolithography processes, and is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP type transistor laser. The substrate 401 is disposed at 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 conductive functions. The first emitter 402 is disposed and connected above the substrate 401, and 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 arranged 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 the refractive index of the quantum well layer 404, so as to confine the first part of the light field in the single longitudinal mode transistor laser to the lower cladding layer 403, the upper cladding layer 405 and the non-doped region of the quantum well layer 405, and the photons of the second part of the light field are absorbed by the doped region and the substrate 401, and the part of the lower cladding layer 403 and the upper cladding layer 405 close to the quantum well layer 404 is the main waveguide transmission light wave. The proportion of the first part of the light field is much greater than the proportion of the second part of the light field. The base electrode contact layer 302 is arranged and connected above the base 406. The base electrode contact layer 302 is arranged on both sides of the second emitter 407. The collector-level periodic gain coupling electrode metal contact layer 303 is arranged and connected above the second emitter 407. When the width of the collector-level periodic gain-coupled electrode metal contact layer 303 of the single longitudinal mode transistor laser 200 is an integer multiple of half the wavelength, the lasing ability of the single longitudinal mode transistor laser 200 in the resonant cavity is enhanced to complete the laser mode selection. In order to maximize the ability to select a single longitudinal mode while ensuring low loss, the present 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, causing the refractive index in the active region to change periodically, 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 mode selection with a periodic refractive index distribution.

[0075] Embodiment 4

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

[0077] In the periodic current injection gain-coupled electrode transistor laser 300, at least one of the multiple electrode contact layers includes an emitter-level periodic gain-coupled electrode metal contact layer 501 that has been processed by two photolithography processes, and is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser. The substrate 601 is used to support the epitaxial structure of the laser device and provide insulation or conductivity. The refractive index of the lower cladding 603 and the upper cladding 605 is lower than the refractive index of the quantum well layer 604, so as to confine the first part of the light field in the single longitudinal mode transistor laser to the non-doped area of ​​the lower cladding 603, the upper cladding 605 and the quantum well layer 605, and the photons of the second part of the light field are absorbed by the doped area and the substrate 601. The part of the lower cladding 603 and the upper cladding 605 close to the quantum well layer 604 is the main waveguide transmission light wave, and the proportion of the first part of the light field is much greater than the proportion of the second part of the light field. When the width of the metal contact layer 501 of the emission-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, and the active region sets up a quantum well active region and a cladding between the N-type base and the P-type emitter. The gain distribution in the active region is regulated by regulating the injection of base electrons. 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 great impact on the gain coupling. Therefore, the gain coupling structure of the NPN structure should be the modified design of this patent.

[0079] Embodiment 5

[0080] Based on Example 1, please refer to Figures 13 to 16 , among which, in Fig.15 In the present invention, a periodic current injection gain-coupled electrode transistor laser 400 is proposed, 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 808, and a second emitter 809. In the periodic current injection gain-coupled electrode transistor laser 400, at least one of the multiple electrode contact layers includes a base periodic gain-coupled electrode metal contact layer 702 that has been processed by two photolithography processes, and each layer is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP type transistor laser. The substrate 801 is arranged at the bottom layer of the periodic current injection gain-coupled electrode transistor laser, and the substrate 801 is used to support the epitaxial structure of the laser device and provide insulation or conductivity. The first emitter 802 is disposed and connected above the substrate 801, and the first emitter 802 is used to transmit the emitter current. The emitter electrode contact layer 701 is disposed and connected above the first emitter 802. The 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. The quantum well layer 804 is disposed and connected above the lower cladding layer 803.

[0081] The upper cladding 805 is arranged above the quantum well layer 804. The quantum well layer 804 is arranged between the lower cladding 803 and the upper cladding 805. The refractive index of the lower cladding 803 and the upper cladding 805 is lower than the refractive index of the quantum well layer 804, so as to confine the first part of the light field in the single longitudinal mode transistor laser to the non-doped area of ​​the lower cladding 803, the upper cladding 805 and the quantum well layer 805, and the photons of the second part of the light field are absorbed by the doped area and the substrate 801, and the part of the lower cladding 803 and the upper cladding 805 close to the quantum well layer 804 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. The confinement layer conductive region 807 is arranged and connected above the upper cladding 805. The limiting layer insulating window 806 is arranged and connected above the upper cladding layer 805, and the limiting layer insulating window 806 is arranged on both sides of the limiting layer conductive area 807, so as to ensure that the carriers are only transported from the limiting layer conductive area 807 inside the conductive insulating window, and limit the position of the radiation recombination center and the light spot. The base 808 is arranged and connected above the limiting layer insulating window 806 and the limiting layer conductive area 807, and the base 808 is used to transmit the base current. The second emitter 809 is arranged and connected above the base 808. The base periodic gain coupling electrode metal contact layer 702 is arranged and connected above the base 808. The base periodic gain coupling electrode metal contact layer 702 is arranged on both sides of the second emitter 809. The collector electrode contact layer 703 of the periodic current injection gain coupling electrode transistor laser 400 is arranged and connected above the second emitter 809. When the width of the base periodic gain coupling electrode metal contact layer 702 is an integral multiple of half the wavelength, the lasing ability of the single longitudinal mode transistor laser in the resonant cavity is enhanced to complete the laser mode selection.

[0082] In summary, the periodic grating structure used in the present application is an etching to form a current injection window, 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 allows it to prepare gain-coupled periodic electrode structures on all three electrodes. The advantage of the gain-coupled 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 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, Fig.13The single-layer restriction layer structure described in the specification can also add a second restriction layer to the lower waveguide to improve the restriction 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 convert 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 restriction 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 combination 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] Embodiment 6

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

[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 comprises 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 at the bottom 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 conduction;

[0088] A third setting module, used for setting and connecting the first emitter and the second emitter above or below the substrate, so as to transmit the emitter current;

[0089] A fourth setting module, used for setting the lower cladding layer above the substrate;

[0090] A fifth setting module, used for setting the quantum well layer above the lower cladding layer;

[0091] A sixth setting module is used 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 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;

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

[0093] an eighth setting module, used to set the collector above the substrate, the collector being used 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 ability of the single longitudinal mode transistor laser system in the resonant cavity is enhanced to complete the laser mode selection.

[0095] Embodiment 7

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

[0097] The periodic current injection gain-coupled electrode transistor laser 100 comprises 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, for setting at least one of the plurality of electrode contact layers to include a base-level periodic gain coupling electrode metal contact layer 102 that is processed 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, used to set the substrate 201 on the bottom layer of the periodic current injection gain-coupled electrode transistor laser 100, wherein the substrate is used to support the epitaxial structure of the laser device and provide insulation or conduction;

[0100] An 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, used for setting and connecting the emitter electrode contact layer 101 above the first emitter 202;

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

[0103] A fourteenth setting module, used for setting and connecting the quantum well layer 204 above the lower cladding layer;

[0104] A fifteenth setting module is used 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 the first part of the light field in the single longitudinal mode transistor laser system to the non-doped region of the lower cladding layer 203, the upper cladding layer 205 and the quantum well layer 205, and the photons of the second part of the light field are absorbed by the doped region and the substrate 201, and 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; 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;

[0105] A sixteenth setting module, used for setting and connecting the base electrode 206 above the upper cladding layer 205, wherein the base electrode 206 is used for transmitting a base current;

[0106] A seventeenth setting module, used for setting and connecting 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, used for setting and connecting 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, used for setting and connecting 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] Embodiment 8

[0111] Based on the third embodiment, the single longitudinal mode transistor laser system includes (please refer again to Figure 7 ): A 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, used for setting at least one of the plurality of electrode contact layers to include a collector-level periodic gain coupling electrode metal contact layer 303 that has been through two photolithography processes, and is sequentially grown in a vertical direction through metal organic chemical vapor deposition to form a PNP transistor laser;

[0114] A twenty-first setting module, used to set the substrate 401 on the bottom layer of the periodic current injection gain-coupled electrode transistor laser 200, wherein 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, used for setting and connecting the first emitter 402 above the substrate 401, wherein the first emitter 402 is used for transmitting an emitter current;

[0116] A twenty-third setting module, used for setting and connecting the emitter electrode contact layer 301 above the first emitter 402;

[0117] A twenty-fourth setting module, used for setting and connecting 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, used for setting and connecting the quantum well layer 404 above the lower cladding layer 403;

[0119] A twenty-sixth setting module is used 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 the first part of the light field in the single longitudinal mode transistor laser system to the non-doped region of the lower cladding layer 403, the upper cladding layer 405 and the quantum well layer 405, and the photons of the second part of the light field are absorbed by the doped region and the substrate 401, and the parts of the lower cladding layer 403 and the upper cladding layer 405 close to the quantum well layer 404 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;

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

[0121] A twenty-eighth setting module, used for setting and connecting the second emitter 407 above the base 406;

[0122] A twenty-ninth setting module, used for setting and connecting the 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 407;

[0123] a thirtieth setting module, used for setting and connecting the collector-level periodic gain coupling electrode metal contact layer 303 above the second emitter 407;

[0124] When the width of the collector-level 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] Embodiment 9

[0126] Based on the fourth embodiment, the single longitudinal mode transistor laser system includes (please refer again to Fig.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, used 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 that has been through two photolithography processes, and to grow sequentially in a vertical direction through metal organic chemical vapor deposition to form a PNP transistor laser;

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

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

[0130] A thirty-third setting module, 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, used for setting and connecting the quantum well layer 604 above the lower cladding layer 403;

[0133] A thirty-sixth setting module is used 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 the first part of the light field in the single longitudinal mode transistor laser system to the non-doped region of the lower cladding layer 603, the upper cladding layer 605 and the quantum well layer 605, and the photons of the second part of the light field are absorbed by the doped region and the substrate 601, and the part of the lower cladding layer 603 and the upper cladding layer 605 close to the quantum well layer 604 is the main waveguide transmission light wave; 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;

[0134] A thirty-seventh setting module, used for setting and connecting the base electrode 606 above the upper cladding layer 605, wherein the base electrode 606 is used for transmitting a base current;

[0135] A thirty-eighth setting module, used for setting and connecting the second emitter 607 above the base 606;

[0136] A thirty-ninth setting module, used for setting and connecting the 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, used for setting and connecting 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] Embodiment 10

[0140] Based on the fifth embodiment, the single longitudinal mode transistor laser system includes (please refer again to Fig.15 ): a 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, used 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 that is processed 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, used to set the substrate 801 on the bottom layer of the periodic current injection gain-coupled electrode transistor laser 400, wherein 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 is used to set and connect the first emitter 802 above the substrate 801, and the first emitter 802 is used to transmit the emitter current;

[0145] A 44th setting module, used for setting and connecting the emitter electrode contact layer 701 above the first emitter 802;

[0146] A forty-fifth setting module is used 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 forty-sixth setting module is used to set and connect the quantum well layer 804 above the lower cladding layer 803;

[0148] A forty-seventh setting module is used 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 the first part of the light field in the single longitudinal mode transistor laser system to the non-doped region of the lower cladding layer 803, the upper cladding layer 805 and the quantum well layer 805, and the photons of the second part of the light field are absorbed by the doped region and the substrate 801, and the part of the lower cladding layer 803 and the upper cladding layer 805 close to the quantum well layer 804 is the main waveguide transmission light wave; 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;

[0149] A 48th setting module, used for setting and connecting the limiting layer conductive area 807 above the upper cladding layer 805;

[0150] A forty-ninth setting module is used to set and connect the limiting layer insulating window 806 above the upper cladding layer 805, and the limiting layer insulating window 806 is set on both sides of the limiting layer conductive area 807 to ensure that carriers are only transported from the limiting layer conductive area 807 inside the conductive insulating window, thereby limiting the position of the radiation recombination center and the light spot;

[0151] A fiftieth setting module, used for setting and connecting the base electrode 808 above the restriction layer insulating window 806 and the restriction layer conductive region 807, the base electrode 808 being used for transmitting base current;

[0152] A fifty-first setting module, used for setting and connecting the second emitter 809 above the base 808;

[0153] A fifty-second setting module, configured to set and connect the base periodic gain coupling electrode metal contact layer 702 above the base electrode 808, wherein the base 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, used for setting and connecting the collector electrode contact layer 703 above the second emitter 809;

[0155] When the width of the base 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 to complete the laser mode selection.

[0156] It should be noted that those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the above-described device and unit can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In several embodiments provided in the present application, the coupling between modules can be electrical, mechanical or other forms of coupling. In addition, each functional module in each embodiment of the present application can be integrated in a processing module, or each module can exist physically separately, or two or more modules can be integrated in one module. The above-mentioned integrated module 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 cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0158] The above specific implementations of the present invention do not constitute a limitation on the protection scope 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 protection scope 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 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; The substrate is arranged at the bottom 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 conduction; The first emitter and the second emitter are arranged and connected above or below the substrate to transmit emitter current; The lower cladding layer is disposed above the substrate; The quantum well layer is arranged 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 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; The base is disposed above the substrate, and the base is used to transmit a base current; The collector is disposed above the substrate, and is used to transmit collector current; When the width of the metal contact layer of the periodic gain coupling electrode is an integral 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 to complete the laser mode selection.

2. The single longitudinal mode transistor laser based on the periodic current injection structure according to claim 1, characterized in that: At least one of the plurality of electrode contact layers includes a base-level periodic gain coupling electrode metal contact layer that is processed by two photolithography processes, and is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser; The substrate is arranged at the bottom 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 conduction; The first emitter is arranged and connected above or below the substrate, and the first emitter is used to transmit an 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 indexes of the lower cladding layer and the upper cladding layer are 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 regions 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; The base electrode is arranged and connected above the upper cladding layer, and the base electrode is used to transmit the base current; The base periodic gain coupling electrode metal contact layer is arranged and connected above the base electrode, wherein the base electrode and the base periodic gain coupling electrode contact layer form an ohmic contact; The second emitter is arranged and connected above the base, and the base-level periodic gain coupling electrode metal contact layer is arranged on both sides of the second emitter; The collector electrode contact layer is arranged and connected above the second emitter; When the width of the base periodic gain coupling electrode metal contact layer is an integral 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 to complete the laser mode selection.

3. The single longitudinal mode transistor laser based on the periodic current injection structure according to claim 1, characterized in that: At least one of the plurality of electrode contact layers includes a collector-level periodic gain coupling electrode metal contact layer that is processed by two photolithography processes, and is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser; The substrate is arranged at the bottom 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 conduction; The first emitter is arranged and connected above the substrate, and the first emitter is used to transmit an 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 indexes of the lower cladding layer and the upper cladding layer are 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 regions 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; The base electrode is arranged and connected above the upper cladding layer, and the base electrode is used to transmit the base current; The second emitter is arranged and connected above the base; The base electrode contact layer is arranged and connected above the base electrode, wherein the base electrode contact layer is arranged on both sides of the second emitter electrode; The collector-level periodic gain-coupling electrode metal contact layer is disposed and connected above the second emitter; When the width of the metal contact layer of the collector-level periodic gain coupling electrode is an integral 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 to complete the laser mode selection.

4. The single longitudinal mode transistor laser based on the periodic current injection structure according to claim 1, characterized in that: At least one of the plurality of electrode contact layers includes an emitter-level periodic gain coupling electrode metal contact layer that is processed by two photolithography processes, and is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser; The substrate is arranged at the bottom 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 conduction; The first emitter is arranged and connected above the substrate, and the first emitter is used to transmit an emitter current; The emitter-stage periodic gain-coupling electrode metal 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-stage periodic gain coupling electrode metal 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 indexes of the lower cladding layer and the upper cladding layer are 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 regions 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; The base electrode is arranged and connected above the upper cladding layer, and the base electrode is used to transmit the base current; The second emitter is arranged and connected above the base; The base electrode contact layer is arranged and connected above the base electrode, wherein the base electrode 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; When the width of the metal contact layer of the emitter-stage periodic gain coupling electrode is an integral 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 to complete the laser mode selection.

5. The single longitudinal mode transistor laser based on the periodic current injection structure according to claim 1, characterized in that: At least one of the plurality of electrode contact layers includes a base-level periodic gain coupling electrode metal contact layer that is processed by two photolithography processes, and is sequentially grown in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser; The substrate is arranged at the bottom 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 conduction; The first emitter is arranged and connected above the substrate, and the first emitter is used to transmit an 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 indexes of the lower cladding layer and the upper cladding layer are 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 regions 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; A confining layer conductive region, arranged and connected above the upper cladding layer; The limiting layer insulating window is arranged and connected above the upper cladding layer. The limiting layer insulating window is arranged on both sides of the conductive area of ​​the limiting layer to ensure that the carriers are only transported from the conductive area of ​​the limiting layer inside 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 limiting layer and the conductive area of ​​the limiting layer, and the base electrode is used to transmit the 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; When the width of the base periodic gain coupling electrode metal contact layer is an integral 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 to complete the laser mode selection.

6. 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 metal contact layer, a base metal contact layer and a collector metal contact layer; 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; A second setting module is used to set the substrate at the bottom 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 conduction; a third setting module, used for setting and connecting the first emitter and the second emitter above or below the substrate to transmit emitter current; A fourth setting module, used for setting the lower cladding layer above the substrate; A fifth setting module, used for setting the quantum well layer above the lower cladding layer; A sixth setting module is used 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 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; A seventh setting module, used to set the base electrode above the substrate, wherein the base electrode is used to transmit a base current; an eighth setting module, used to set the collector above the substrate, the collector being used to transmit 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 lasing system based on the periodic current injection structure in the resonant cavity is enhanced to complete the laser mode selection.

7. The single longitudinal mode transistor laser system based on a periodic current injection structure according to claim 6, characterized in that: include: 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 that is processed by two photolithography processes, and to grow sequentially in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser; A tenth setting module, used to set the substrate at the bottom 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; An eleventh setting module is used to set and connect the first emitter electrode above or below the substrate, and the first emitter electrode is used to transmit the emitter current. A twelfth setting module, used for setting and connecting an emitter electrode contact layer above the first emitter; A thirteenth setting module, used for setting and connecting 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 fourteenth setting module, used for setting and connecting the quantum well layer above the lower cladding layer; A fifteenth setting module is used 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 indexes of the lower cladding layer and the upper cladding layer are 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 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 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; A sixteenth setting module, used for setting and connecting the base electrode above the upper cladding layer, the base electrode being used for transmitting a base current; A seventeenth setting module, used for setting and connecting the base periodic gain coupling electrode metal contact layer above the base electrode, wherein the base electrode and the base periodic gain coupling electrode contact layer form an ohmic contact; An eighteenth setting module, used for setting and connecting the second emitter above the base, and the base-level periodic gain coupling electrode metal contact layer is set on both sides of the second emitter; A nineteenth setting module, used for setting and connecting the collector electrode contact layer above the second emitter; When the width of the base periodic gain coupling electrode metal contact layer is an integral 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 to complete the laser mode selection.

8. The single longitudinal mode transistor laser system based on a periodic current injection structure according to claim 6, characterized in that: include: A twentieth setting module, used for setting at least one of the plurality of electrode contact layers to include a collector-level periodic gain coupling electrode metal contact layer that has been through two photolithography processes, and is sequentially grown in a vertical direction through metal organic chemical vapor deposition to form a PNP transistor laser; A twenty-first setting module, used to set the substrate at the bottom layer of the periodic current injection gain-coupled electrode transistor laser, the substrate is used to support the epitaxial structure of the laser device and provide insulation or conduction; a twenty-second setting module, used for setting and connecting the first emitter electrode above the substrate, wherein the first emitter electrode is used for transmitting an emitter current; A twenty-third setting module, used for setting and connecting the emitter electrode contact layer above the first emitter; A twenty-fourth setting module, used for setting and connecting 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 twenty-fifth setting module, used for setting and connecting the quantum well layer above the lower cladding layer; A twenty-sixth setting module is used 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 indexes of the lower cladding layer and the upper cladding layer are 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 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 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; A twenty-seventh setting module, used to set and connect the base electrode above the upper cladding layer, the base electrode being used to transmit a base current; A twenty-eighth setting module, used for setting and connecting the second emitter above the base; a twenty-ninth setting module, configured to set and connect the base electrode contact layer above the base electrode, wherein the base electrode contact layer is set on both sides of the second emitter electrode; A 30th setting module, used for setting and connecting the collector-level periodic gain coupling electrode metal contact layer above the second emitter; When the width of the metal contact layer of the collector-level periodic gain coupling electrode is an integral 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 to complete the laser mode selection.

9. The single longitudinal mode transistor laser system based on a periodic current injection structure according to claim 6, characterized in that: include: A 30th setting module, used to set at least one of the plurality of electrode contact layers to include an emitter-level periodic gain coupling electrode metal contact layer that has been through two photolithography processes, and to grow sequentially in a vertical direction through metal organic chemical vapor deposition to form a PNP transistor laser; A thirty-first setting module is used to set the substrate at 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 conduction; a thirty-second 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 thirty-third setting module is used to set and connect the emitter-stage periodic gain coupling electrode metal contact layer above the first emitter; A thirty-fourth setting module is used to set and connect the lower cladding layer above the first emitter, wherein the emitter-stage periodic gain coupling electrode metal contact layer is set on both sides of the lower cladding layer; A thirty-fifth setting module is used to set and connect the quantum well layer above the lower cladding layer; A thirty-sixth setting module is used 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 indexes of the lower cladding layer and the upper cladding layer are 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 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 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; A thirty-seventh setting module, used to set and connect the base electrode above the upper cladding layer, the base electrode being used to transmit a base current; A thirty-eighth setting module, used for setting and connecting the second emitter above the base; A thirty-ninth setting module, used for setting and connecting the base electrode contact layer above the base electrode, wherein the base electrode contact layer is set on both sides of the second emitter electrode; a 40th setting module, used for setting and connecting the collector electrode contact layer above the second emitter; When the width of the metal contact layer of the emitter periodic gain coupling electrode is an integral 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 to complete the laser mode selection.

10. The single longitudinal mode transistor laser system based on a periodic current injection structure according to claim 6, characterized in that: include: A forty-first setting module, used to set at least one of the plurality of electrode contact layers to include a base-level periodic gain coupling electrode metal contact layer that has been subjected to two photolithography processes, and to grow sequentially in a vertical direction by metal organic chemical vapor deposition to form a PNP transistor laser; A forty-second setting module is used to set the substrate at the bottom 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; A forty-third setting module, used for setting and connecting the first emitter electrode above the substrate, wherein the first emitter electrode is used for transmitting an emitter current; A forty-fourth setting module, used for setting and connecting the emitter electrode contact layer above the first emitter; A forty-fifth setting module, used for setting and connecting 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 setting module is used to set and connect the quantum well layer above the lower cladding layer; A forty-seventh setting module is used 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 part of the light field in the single longitudinal mode transistor laser system 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 part of the lower cladding layer and the upper cladding layer close to the quantum well layer is the main waveguide transmission light wave; 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 48th setting module, used for setting and connecting the limiting layer conductive area above the upper cladding layer; A forty-ninth setting module is used to set and connect the limiting layer insulating window above the upper cladding layer, wherein the limiting layer insulating window is set on both sides of the limiting layer conductive area to ensure that carriers are only transported from the limiting layer conductive area inside the conductive insulating window, thereby limiting the position of the radiation recombination center and the light spot; A fiftieth setting module, used for setting and connecting the base electrode above the restriction layer insulating window and the restriction layer conductive region, the base electrode being used for transmitting base current; A fifty-first setting module, used for setting and connecting the second emitter above the base; A fifty-second setting module, used for setting and connecting 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, used for setting and connecting the collector electrode contact layer above the second emitter; When the width of the base periodic gain coupling electrode metal contact layer is an integral 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 to complete the laser mode selection.

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