Same-direction dual-output semiconductor laser chip
By introducing a U- or V-type laser waveguide structure into semiconductor laser chips, the same-direction dual output port of a single laser chip is realized, solving the problem of multiple output ports requiring multiple chips, reducing costs and improving yields.
Patent Information
- Application Number
- CN202421857136.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-02
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-08-02
AI Technical Summary
Existing high-power semiconductor laser chips require multiple chips to implement multiple output ports, resulting in increased chip area, higher cost and reduced yield.
The U- or V-type laser waveguide structure is adopted to enable a single laser chip to provide dual output ports in the same direction, driven by a single electrode, and a reverse-reflection film is plated on the light exit end surface.
The function of a single laser chip to provide multiple light sources is realized, reducing chip area and cost, while improving yield.
Smart Images
Figure CN222601704U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a semiconductor laser chip, in particular to a semiconductor laser chip with co-directional double outputs. Background Art
[0002] Semiconductor laser chips are widely used in the fields of communications and industrial processing. In the field of optical communications, with the huge growth in demand for bandwidth, the development of higher-speed transmission technology has become inevitable. One important direction is silicon photonic integration based on silicon-based materials and processes. However, since silicon material itself is not a good light-emitting material, it requires the integration of high-power laser chips based on III-V semiconductors with silicon-based modulators and other chips. Therefore, high-power semiconductor laser chips are the core components for the success of 400G / 800G and even higher-speed silicon photonic chip technology in the future.
[0003] At present, the 400G / 800GDR4 / DR8 silicon photonic modules of the DR (Datacenter Reach) series used in data centers on a large scale generally require two to four high-power semiconductor laser chips. Figure 1 As shown, the existing 400G / 800G silicon photonic engine includes a first laser chip 1, a second laser chip 2 and a silicon photonic chip 3; the first laser chip 1 and the second laser chip 2 are placed together with the silicon photonic chip 3 on a substrate 4; the silicon photonic chip 3 is composed of four silicon photonic modulators 5a, 5b, 6a, 6b, and a first silicon photonic beam splitter 7 and a second silicon photonic beam splitter 8 connecting the first laser chip 1 and the second laser chip 2 with the silicon photonic modulators 5a, 5b, 6a, 6b; the output end of the first laser chip 1 is connected to the input end of the first silicon photonic beam splitter 7, and the input ends of the silicon photonic modulators 5a and 5b are connected to the two output ends of the first silicon photonic beam splitter 7. In this way, the output continuous light of the first laser chip 1 enters the two silicon photonic modulators 5a and 5b through the first silicon photonic beam splitter 7 and is modulated respectively. Similarly, the output continuous light of the second laser chip 2 enters the two silicon photonic modulators 6a and 6b through the second silicon photonic beam splitter 8 and is modulated respectively. The optical coupling between the first laser chip 1 and the second laser chip 2 and the first silicon optical splitter 7 and the second silicon optical splitter 8 can be achieved by direct docking or by coupling through one or two lenses ( Figure 1 Lens not shown).
[0004] For 800G / 1.6T optical engines, four to eight high-power laser chips will be required. Although silicon photonic chips integrate multiple components, they are limited by the power and size of the laser. Currently, a single silicon photonic chip of the 400G and above DR series requires two or more laser chips. If the number of laser chips used can be reduced without increasing the area of the laser chip, it will not only reduce the cost of the laser chip itself used in the silicon photonic chip engine, but also simplify the packaging of the silicon photonic engine, further reducing the overall cost.
[0005] One solution is to make two laser light emitting waveguides directly on a chip. Figure 2 As shown, there are two independent laser waveguides 9a and 9b on the laser chip 9, and two electrodes 9c and 9d drive the laser waveguides 9a and 9b respectively; the light-emitting cavity surface of the laser chip 9 is coated with an anti-reflection film (AR) 9e, and the back cavity surface of the laser chip 9 is coated with a high-reflection film (HR). The laser waveguides 9a and 9b work completely independently. The advantage of this structure is that it reduces the area of the laser chip, but due to the yield limit of the single-mode laser, this structure will greatly reduce the overall yield of the laser chip. Generally, the yield of a single-mode laser is about 60-80%, and if two lasers meet the performance requirements at the same time, the overall yield will be reduced to about 36-64%. In addition, the laser waveguides 9a and 9b still need to be tested and screened separately, so this structure has limited cost reduction.
[0006] Both of the above lasers have defects. Specifically, Figure 1 The first laser chip 1 shown includes a laser waveguide 1a and an electrode 1b, and the two ports of the laser waveguide 1a are perpendicular to the two end faces of the first laser chip 1. The two cavity surfaces of the first laser chip 1 are respectively coated with an AR (anti-reflection) film and an HR (high reflection) film. This structure determines that only one of the ports can be used to connect to an external optical element. In order not to waste the output power of the other port, the traditional semiconductor laser is coated with an AR (anti-reflection) film on the light-emitting end face and a high reflection (HR) film on the other end face. Although this structure increases the laser output power, the phase randomness caused by the uncertain cleavage position of the HR end chip leads to the loss of single-mode yield of the single-mode laser.
[0007] Figure 2 The laser 9 shown is a conventional semiconductor laser chip with an additional laser waveguide, which can provide two light output ports on one chip. However, this simple increase in the number of waveguides will significantly reduce the yield of the laser chip, and the two lasers still need to be tested and selected separately to ensure that both lasers meet the requirements, and two driving current sources are required, so the chip cost will not be significantly reduced. Utility Model Content
[0008] The technical problem to be solved by the utility model is to provide a semiconductor laser chip with dual outputs in the same direction. The chip has two ports for emitting light from the same end face and is driven by a single electrode.
[0009] In order to solve the above technical problems, the technical solution of the semiconductor laser chip with dual output in the same direction of the utility model is:
[0010] The invention comprises a U-shaped laser waveguide; the output end of the U-shaped laser waveguide is two parallel optical waveguides; the two parallel optical waveguides are connected at the other end, i.e., the non-light-emitting end, through a third optical waveguide; the U-shaped laser waveguide is driven by the same electrode; the light-emitting end of the laser chip is coated with an anti-reflection (AR) film; the U-shaped laser waveguide at least comprises, from top to bottom, a P-type semiconductor material, an active layer, and an N-type semiconductor material; and the U-shaped laser waveguide is grown on a semiconductor substrate.
[0011] In another embodiment, the U-shaped laser waveguide is a ridge waveguide structure; or, the U-shaped laser waveguide is a buried waveguide structure.
[0012] In another embodiment, part or all of the U-shaped laser waveguide has a grating structure.
[0013] In another embodiment, the active layer is a quantum well structure.
[0014] In another embodiment, the third optical waveguide is a bent optical waveguide; two parallel optical waveguides and the bent optical waveguide constitute the U-shaped laser waveguide.
[0015] In another embodiment, the bent optical waveguide and the parallel optical waveguide have the same structure.
[0016] In another embodiment, the bent optical waveguide is a deep ridge waveguide.
[0017] In another embodiment, the lateral refractive index difference of the bent optical waveguide is greater than the lateral refractive index difference of the parallel optical waveguide.
[0018] In another embodiment, the third optical waveguide is a vertical optical waveguide; the two parallel optical waveguides are connected to the vertical optical waveguide through reflectors respectively; the angle between the normal direction of the reflector and the parallel optical waveguide is greater than the critical angle of total reflection; and the angle between the two reflectors is 90 degrees.
[0019] In another embodiment, the angle between the normal direction of the reflector and the parallel optical waveguide is 45 degrees.
[0020] In another embodiment, the parallel optical waveguide and the vertical optical waveguide form a tapered structure near the reflection surface.
[0021] In another embodiment, the reflective surface of the reflector is formed by a dry etching method.
[0022] In another embodiment, the vertical optical waveguide and the parallel optical waveguide have the same structure.
[0023] In another embodiment, the effective refractive index of the U-shaped laser waveguide in the horizontal direction is higher than that of the semiconductor structures on both sides; and the positive electrode of the electrode is located above the P-type semiconductor.
[0024] The utility model also provides another semiconductor laser chip with dual outputs in the same direction, and its technical solution is:
[0025] The invention comprises a V-shaped laser waveguide; the V-shaped laser waveguide is composed of two optical waveguides; the output ends of the two optical waveguides are parallel to the light output end; the other ends of the two optical waveguides are inclined at an angle with the other end face of the laser to form a V-shaped structure; the V-shaped laser waveguide is driven by the same electrode; the light output end is coated with an anti-reflection film; the other end face of the laser is coated with a high-reflection film; the V-shaped laser waveguide at least comprises, from top to bottom, a P-type semiconductor material, an active layer, and an N-type semiconductor material; and the V-shaped laser waveguide is grown on a semiconductor substrate.
[0026] In another embodiment, the inclination angle is between 3 and 15 degrees.
[0027] In another embodiment, the other end of the V-shaped laser waveguide has a tapered waveguide structure.
[0028] In another embodiment, part or all of the V-shaped laser waveguide has a grating structure.
[0029] In another embodiment, the semiconductor laser chip is connected to the multi-input port of the external optical chip by direct docking or lens coupling.
[0030] In another embodiment, the width of the laser waveguide is between 1 and 10 microns.
[0031] In another embodiment, the distance between the two waveguides at the light output end of the laser chip is between 10 and 1000 microns.
[0032] In another embodiment, the effective refractive index of the V-shaped laser waveguide in the horizontal direction is higher than that of the semiconductor structures on both sides; and the positive electrode of the electrode is located above the P-type semiconductor.
[0033] In another embodiment, the V-shaped laser waveguide is a ridge waveguide structure; or, the V-shaped laser waveguide is a buried waveguide structure.
[0034] In another embodiment, the semiconductor substrate is an InP or GaAs semiconductor.
[0035] In another embodiment, the reflectivity of the anti-reflection film is less than 50%.
[0036] In another embodiment, the semiconductor material is a Group III-V compound semiconductor.
[0037] The technical effects that can be achieved by the utility model are:
[0038] The utility model realizes that a single laser has dual output ports in the same direction by introducing a U-shaped or V-shaped optical waveguide. One laser can provide two light sources to an external optical element at the same time, providing a simple and low-cost technical solution for an optical engine requiring multiple light sources.
[0039] The utility model introduces a U-shaped or V-shaped laser waveguide structure, which changes the structure of the two ports of the traditional semiconductor laser being one in front and one behind, and realizes that the same laser forms two light output ports on the light output end face, so that a laser chip can simultaneously provide two light sources to an additional optical element without the need for two independent lasers. Compared with two independent lasers, the utility model not only reduces the chip size, but also simplifies the drive circuit because of the single electrode drive. In addition, because the two ports come from the same laser, only one laser needs to be tested instead of two. Compared with two independent lasers, the yield of the laser with the same-direction dual ports of the utility model has also been improved, which will greatly reduce the cost of high-power lasers used in silicon photonic chips.
[0040] The utility model is compatible with the material growth and process technology of existing laser chips, and does not need to develop new growth and process, and can be applied to all multi-channel semiconductor chips. Therefore, the technical solution of the utility model can ensure large-scale production and improve the yield rate of dynamic lasers. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] It should be understood by those skilled in the art that the following description is only intended to schematically illustrate the principles of the present invention, which can be applied in a variety of ways to achieve many different alternative embodiments. These descriptions are only used to illustrate the general principles of the teachings of the present invention and are not intended to limit the utility model concepts disclosed herein.
[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the general description above and the detailed description of the drawings below, are used to explain the principles of the present invention.
[0043] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:
[0044] Figure 1It is a schematic diagram of the structure of a 400G / 800G silicon photonic engine with two independent laser chips in the prior art;
[0045] Figure 2 It is a schematic diagram of integrating two independent lasers with dual output ends in the prior art;
[0046] Figure 3 It is a schematic diagram of a first embodiment of a semiconductor laser chip with dual outputs in the same direction according to the utility model;
[0047] Figure 4a is a cross-sectional schematic diagram of a ridge waveguide structure;
[0048] Figure 4b is a schematic cross-sectional view of a buried waveguide structure;
[0049] Figure 4c is a cross-sectional schematic diagram of a deep ridge waveguide structure;
[0050] Figure 5 This is a schematic diagram of the structure of a 400G / 800G optical engine composed of a U-shaped co-directional dual-port laser and a silicon photonic chip;
[0051] Figure 6 Schematic diagram of the second embodiment of the utility model; it uses a U-shaped laser with dual outputs in the same direction formed by two reflecting surfaces;
[0052] Figure 7 This is a schematic diagram of another U-shaped laser with two reflecting surfaces and dual outputs in the same direction;
[0053] Figure 8 It is a schematic diagram of the third embodiment of the present utility model.
[0054] Description of reference numerals in the figures:
[0055] Prior art
[0056] 1 is the first laser, 2 is the second laser,
[0057] 3 is the silicon photonic chip, 4 is the substrate,
[0058] 5a, 5b, 6a, and 6b are silicon optical modulators.
[0059] 7 is a first silicon optical splitter, 8 is a second silicon optical splitter,
[0060] 1a is the laser waveguide, 1b is the electrode,
[0061] AR is the anti-reflection film on the laser light-emitting surface, and HR is the high-reflection film on the rear end of the laser.
[0062] 9 is a chip integrating two independent lasers, 9a and 9b are two independent laser waveguides,
[0063] 9c and 9d are two independent electrodes, 9e is an anti-reflection film,
[0064] 9f is a high reflection film.
[0065] The utility model
[0066] 10 is a U-shaped semiconductor laser with dual output ends in the same direction.
[0067] 10a and 10b are two parallel semiconductor laser waveguides.
[0068] 10c is a bent optical waveguide, 10d is an electrode,
[0069] 10a1 is a semiconductor substrate, 10a2 is an N-type semiconductor material,
[0070] 10a3 is an active layer, 10a4 is a P-type semiconductor material,
[0071] 10d1 is the P-side electrode, 10d2 is the N-side electrode,
[0072] 10a5 is a buried semiconductor material, 10m1 and 10m2 are reflective surfaces,
[0073] 10e is a vertical optical waveguide. DETAILED DESCRIPTION
[0074] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution of the embodiment of the utility model will be clearly and completely described in conjunction with the drawings of the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the described embodiment of the utility model, all other embodiments obtained by ordinary technicians in the field without creative work belong to the scope of protection of the utility model. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the utility model belongs. The "first", "second" and similar words used in this article do not indicate any order, quantity or importance, but are only used to distinguish different components. "Including" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.
[0075] The core idea of the utility model is to introduce a U-shaped or V-shaped laser waveguide structure to solve the limitation that the two ports of the traditional semiconductor laser are connected one after the other and multiple laser chips are required to couple with the multi-port external optical chip.
[0076] Specifically, the utility model moves the rear ports of the two ports of a traditional laser, one in front and one in the back, to the same cavity surface through a U-shaped or V-shaped waveguide structure, so that a single laser can provide two co-directional output optical ports. While increasing the effective use area of the laser chip, the time for laser testing and screening is not increased, and the output yield of the laser is not affected, providing an effective and low-cost solution for optical chips that require multi-port light sources.
[0077] In order to achieve the purpose of the above-mentioned single laser chip having dual output ports in the same direction to provide two light sources for external optical components at the same time, the utility model is described through the following embodiments.
[0078] like Figure 3 As shown in the figure, as the first embodiment of the utility model, the semiconductor laser chip 10 includes two parallel optical waveguides 10a and 10b, a bent optical waveguide 10c connecting the parallel optical waveguides 10a and 10b, and an electrode 10d for simultaneously providing driving current to the parallel optical waveguides 10a, 10b and the bent optical waveguide 10c; the output light end faces of the parallel optical waveguides 10a and 10b are coated with an anti-reflection film AR;
[0079] Preferably, the parallel optical waveguides 10a, 10b are perpendicular to the output light end face.
[0080] like Figure 4a As shown, the basic structure of the parallel optical waveguides 10a, 10b and the curved optical waveguide 10c includes, from bottom to top, a semiconductor substrate 10a1, an N-type semiconductor 10a2, an active layer 10a3, a P-type semiconductor 10a4, and an electrode 10d1 located above the P-type semiconductor and an electrode 10d2 located below the N-type semiconductor. The active layer 10a3 is the light-emitting region of the semiconductor laser chip 10, which together with the N-type semiconductor 10a2 and the P-type semiconductor 10a4 provides vertical optical and electrical confinement of the laser waveguides 10a and 10b. The lateral optical and electrical confinement is achieved through the lateral structure.
[0081] The horizontal structure can adopt two structures, one is as follows Figure 4a The ridge waveguide shown is formed by etching away a portion of the P-type semiconductor material 10a4; the other is as shown in Figure 4b The buried waveguide structure shown is formed by etching away the P-type semiconductor, the active layer 10a3 and part of the N-type semiconductor 10a2 and then epitaxially regrowing to form lateral optical and electrical confinement.
[0082] If the bending radius of the curved optical waveguide 10c is large, the parallel optical waveguides 10a, 10b and the curved optical waveguide 10c can have the same waveguide structure, so they can be completed at one time using the same process as a conventional semiconductor laser. However, for a curved optical waveguide with a smaller bending radius, in order to reduce the optical loss caused by waveguide bending, a larger refractive index difference is generally required to provide stronger lateral light confinement. Therefore, the curved optical waveguide 10c may require a different waveguide structure from the parallel optical waveguides 10a and 10b, such as Figure 4c In the deep ridge waveguide structure shown, part or all of the active region in the lateral direction is etched away to form a large refractive index difference in the lateral direction.
[0083] All the above structures are first deposited on a semiconductor substrate by epitaxial growth (generally metal organic vapor phase epitaxy MOCVD). After the crystal growth is completed, the ridge waveguide structure is formed by etching. For the buried waveguide structure, multiple epitaxial regrowths are required. The width of the ridge waveguide is generally about 2 microns. Etching is generally a combination of dry and wet methods. For the long-wavelength semiconductor lasers required for optical communication, the substrate is generally InP (indium phosphide), and the material of the active layer is InAlGaAs or InGaAsP compound semiconductors of different components. The specific structure of the active layer includes the quantum well in the middle and the respective confinement layers located above and below it. For single longitudinal mode distributed feedback (DFB) lasers, a grating structure is added to the P-type or N-type semiconductor to achieve single-mode output. At this time, the reflectivity of the AR film on the light-emitting surface of the laser is about 0. If it is a multi-mode laser, the reflectivity of the AR film on the light-emitting surface of the laser is generally between 5% and 50%.
[0084] By introducing the curved waveguide 10c to connect the parallel waveguides 10a and 10b, the laser resonant cavity is composed of the parallel waveguides 10a, 10b and the curved waveguide 10c. Without increasing the length of the laser, the laser cavity length is increased by about two times compared with the traditional laser, and the laser power will be increased accordingly, and it is driven by the same electrode 10d. In addition, since there is no back cavity surface of the traditional laser, only one cavity surface coating is required.
[0085] Furthermore, the cavity surface of traditional semiconductor lasers is generally obtained by cleavage. For single-mode distributed feedback DFB lasers, the uncertainty of the mechanical cleavage position determines that the HR coating of the rear cavity surface will inevitably lead to uncontrollable phase, thus affecting the single-mode yield of the laser. The dual-port laser of the utility model will not require HR coating of the rear end surface, thus improving the single-mode yield of the laser. All of these will provide a low-cost co-directional dual-output port laser solution.
[0086] Figure 5 It is a schematic diagram of the integration of the dual-port laser chip 10 and the external optical chip. The distance between the two parallel optical waveguides 10a and 10b of the dual-port laser chip 10 will be determined by the structure of the external optical chip. Therefore, the bending radius of the curved optical waveguide 10c is limited by the size of the external chip on the one hand, and generally a small bending radius is required. On the other hand, the bending radius of the curved optical waveguide is also limited by the lateral refractive index difference and generally cannot be too small.
[0087] Figure 6As a second embodiment, the technical challenge of limited bending radius can be solved. In this embodiment, the connection between the parallel optical waveguides 10a and 10b is achieved through two reflectors 10m1 and 10m2 and a straight waveguide 10e in a vertical direction. The reflectors 10m1 and 10m2 are 90 degrees apart. The light from the parallel optical waveguide 10a enters the vertical optical waveguide 10e after being reflected by the reflector 10m1; the light from the parallel optical waveguide 10b enters the vertical optical waveguide 10e after being reflected by the reflector 10m2. In other words, the two reflectors 10m1 and 10m2 form a 90-degree reflector, allowing the parallel optical waveguides 10a and 10b to be freely connected.
[0088] The refractive index of III-V semiconductor materials used for optical communication is greater than 3. If one side of the reflector is semiconductor material and the other side is air, its critical angle of total reflection is less than 20 degrees, so as long as the angle between the reflective surface and the parallel optical waveguide is greater than 20 degrees, total reflection can be formed. The production of the total reflection surface is completely compatible with the existing semiconductor laser process. After completing the production of all optical waveguides, the P-type semiconductor, active layer and N-type semiconductor of the optical waveguides 10a and 10b are completely etched away at the reflection surfaces 10m1 and 10m2 to form a total reflection surface. Since the etched surface needs to be as flat and vertical as possible, the reflection surface is generally formed by dry etching. The specific etching morphology can be adjusted according to the process. Figure 6 In the example, the reflective surface etching morphology is triangular, of course, it can also be Figure 7 It is not difficult to see that the distance between the two light-emitting ends of the U-shaped laser structure based on the 90-degree reflector will no longer be limited by the radius of the curved waveguide and can be freely arranged according to the requirements of the external optical components.
[0089] Figure 8This is the third embodiment of the utility model. The laser chip 10 with dual output optical ports in the same direction includes two laser waveguides 10a and 10b. The laser waveguides 10a and 10b are placed in parallel at one end (light output end) of the laser chip, but at the other end, the optical waveguide 10a is placed at an angle to the cavity surface. The normal angle between the laser waveguide 10a and the end surface is generally between 2 and 10 degrees, while the laser waveguide 10b is placed at an opposite angle to the cavity surface. The laser waveguides 10a and 10b overlap on the cavity surface to form a V-shaped structure. The light output end of the laser chip is coated with an AR film, and the other end (i.e., the end where the optical waveguides 10a and 10b are tilted) is coated with an HR film. Therefore, the laser from 10a or 10b enters 10b or 10a through the HR end face. This V-shaped waveguide structure is also no longer limited by the bending radius. The distance between the two light output end faces can be very small, and the width of the chip can be greatly reduced. The back cavity surface of the laser chip 10 can be realized by cleavage like a traditional laser, or it can be formed by etching. Taking into account the inaccuracy of the cleavage and etching positions, in order to increase the coupling tolerance between the optical waveguides 10a and 10b, the mode field size of the optical waveguides 10a and 10b at the inclined end can be increased, such as a tapered waveguide structure. Traditional lasers generally use the light output from the back cavity surface as a monitoring signal. In the U-shaped structure, since there is no back cavity surface, it will be impossible to monitor the laser performance through the back cavity surface. However, in the V-shaped structure, by controlling the reflectivity of the HR film, it will be possible to monitor the changes in laser power like a traditional laser. Figure 8 It is a schematic diagram of a light engine with a monitoring detector 9.
[0090] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these changes and modifications.
Claims
1. A semiconductor laser chip with dual outputs in the same direction, characterized in that: comprising a U-shaped laser waveguide; The output end of the U-shaped laser waveguide is two parallel optical waveguides; the two parallel optical waveguides are connected at the other end by a third optical waveguide; the U-shaped laser waveguide is driven by the same electrode; the light output end of the laser chip is coated with an anti-reflection film; The U-shaped laser waveguide at least comprises, from top to bottom, a P-type semiconductor material, an active layer, and an N-type semiconductor material; the U-shaped laser waveguide is grown on a semiconductor substrate.
2. The semiconductor laser chip with dual outputs in the same direction according to claim 1, characterized in that: The U-shaped laser waveguide is a ridge waveguide structure; or, the U-shaped laser waveguide is a buried waveguide structure.
3. The semiconductor laser chip with dual outputs in the same direction according to claim 1, characterized in that: The U-shaped laser waveguide partially or entirely has a grating structure.
4. The semiconductor laser chip with dual outputs in the same direction according to claim 1, characterized in that: The active layer is a quantum well structure.
5. The semiconductor laser chip with dual outputs in the same direction according to claim 1, characterized in that: The third optical waveguide is a bent optical waveguide; the two parallel optical waveguides and the bent optical waveguide constitute the U-shaped laser waveguide.
6. The semiconductor laser chip with dual outputs in the same direction according to claim 5, characterized in that: The bent optical waveguide has the same structure as the parallel optical waveguide.
7. The semiconductor laser chip with dual outputs in the same direction according to claim 5, characterized in that: The bent optical waveguide is a deep ridge waveguide structure.
8. The semiconductor laser chip with dual outputs in the same direction according to claim 1, characterized in that: The third optical waveguide is a vertical optical waveguide; the two parallel optical waveguides are connected to the vertical optical waveguide through reflectors respectively; the angle between the normal direction of the reflector and the parallel optical waveguide is greater than the critical angle of total reflection; the angle between the two reflectors is 90 degrees.
9. The semiconductor laser chip with dual outputs in the same direction according to claim 8, characterized in that: The angle between the normal direction of the reflector and the parallel optical waveguide is 45 degrees.
10. The semiconductor laser chip with dual outputs in the same direction according to claim 8, characterized in that: The parallel optical waveguide and the vertical optical waveguide form a tapered structure near the reflection surface.
11. A semiconductor laser chip with dual outputs in the same direction, characterized in that: comprising a V-shaped laser waveguide; The V-shaped laser waveguide is composed of two optical waveguides; the output ends of the two optical waveguides are parallel to the light output end; the other ends of the two optical waveguides are inclined at an angle to the other end surface of the laser chip to form a V-shaped structure; The V-shaped laser waveguide is driven by the same electrode; the light-emitting end of the laser chip is coated with an anti-reflection film; the other end surface of the laser chip is coated with a high-reflection film; The V-shaped laser waveguide at least comprises, from top to bottom, a P-type semiconductor material, an active layer, and an N-type semiconductor material; the V-shaped laser waveguide is grown on a semiconductor substrate.
12. The semiconductor laser chip with dual outputs in the same direction according to claim 11, characterized in that: The inclination angle is between 3 and 15 degrees.
13. The semiconductor laser chip with dual outputs in the same direction according to claim 11, characterized in that: The other end of the V-shaped laser waveguide has a tapered waveguide structure.
14. The semiconductor laser chip with dual outputs in the same direction according to claim 11, characterized in that: Part or all of the V-shaped laser waveguide has a grating structure.
15. The semiconductor laser chip with dual outputs in the same direction according to claim 1 or 11, characterized in that: The semiconductor laser chip is connected to the multi-input ports of the external optical chip by direct docking or lens coupling.
16. The semiconductor laser chip with dual outputs in the same direction according to claim 1 or 11, characterized in that: The width of the laser waveguide is between 1 and 10 microns; and / or the distance between the two waveguides at the light output end of the laser chip is between 10 and 1000 microns.