Semiconductor laser bar and spectrum beam combining device based on quasi PT symmetry

Abstract

The invention provides a semiconductor laser bar based on quasi-PT symmetry, which is applied to the field of semiconductors, and comprises a plurality of quasi-PT symmetrical semiconductor laser single tubes which are horizontally and tightly arranged, and laser emitted by the plurality of quasi-PT symmetrical semiconductor laser single tubes is not coupled; the quasi-PT symmetrical semiconductor laser single tube comprises an N-type electrode, an N-type substrate layer, an N-type waveguide cover layer, an N-type waveguide layer, barrier layers, potential well layers, a P-type waveguide layer, a P-type waveguide cover layer, a P-type contact layer, a P-type insulating layer and a P-type electrode, wherein the P-type waveguide layer, the P-type waveguide cover layer and the P-type contact layer are respectively provided with a ridge waveguide region. The invention further provides a spectrum beam combining device. Independent light emitted by each semiconductor laser on the bar is synthesized into a beam of light with uniform wavelength distribution intervals through the optical lens and the grating, so that high-power laser output is realized, and the lateral light beam quality of the semiconductor laser bar is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor lasers, and in particular, to a semiconductor laser bar and a spectrum combining device based on quasi-PT symmetry. Background Art

[0002] Semiconductor lasers have the advantages of high electro-optical conversion efficiency, small size, and high reliability, and have developed application needs in the fields of radar detection and fiber coupling. This requires that the laser light source can not only achieve high power output, but also have good beam quality.

[0003] However, wide-stripe lasers that achieve high-power output are often accompanied by multi-side mode lasing, resulting in poor beam quality, which limits the further expansion of its application scenarios. Introducing a parity-time (PT) symmetric structure in a strip laser can effectively reduce the lateral mode of the semiconductor laser and achieve single-mode lasing. However, its ridge width is narrow, and it is easy to cause cavity surface catastrophes when working under high current. This results in the output optical power of the PT-symmetric laser being low when achieving single-side mode lasing (usually a few hundred milliwatts), and increasing the injection current will cause the mode characteristics of the laser to be unstable, which is not conducive to application in scenarios with high brightness requirements. Summary of the invention

[0004] In view of this, the present disclosure provides a quasi-PT symmetric semiconductor laser bar and a spectrum combining device.

[0005] In a first aspect, the embodiments of the present disclosure provide a semiconductor laser bar based on quasi-PT symmetry, comprising a plurality of quasi-PT symmetric semiconductor laser tubes 2, wherein the plurality of quasi-PT symmetric semiconductor laser tubes 2 are closely arranged horizontally, and there is no coupling between the lasers emitted by the plurality of quasi-PT symmetric semiconductor laser tubes 2;

[0006] The quasi-PT symmetric semiconductor laser single tube 2 comprises an N-type electrode 4, an N-type substrate layer 5, an N-type waveguide cap layer 6, an N-type waveguide layer 7, an alternately distributed barrier layer 8 and a potential well layer 9, a P-type waveguide layer 10, a P-type waveguide cap layer 11, a P-type contact layer 12, a P-type insulating layer 13 and a P-type electrode 14 arranged in sequence;

[0007] The P-type waveguide layer 10 , the P-type waveguide cap layer 11 and the P-type contact layer 12 have a ridge waveguide region 3 thereon.

[0008] According to an embodiment of the present disclosure, the ridge waveguide region 3 includes a waveguide array, and the waveguides in the waveguide array are distributed in a symmetrical distribution or an asymmetrical distribution;

[0009] The waveguides in the waveguide array include a gain waveguide 31 and a loss waveguide 32;

[0010] The gain waveguide 31 is the portion of the P-type insulating layer 13 that is not completely covered on the P-type contact layer 12;

[0011] The lossy waveguide 32 is the portion completely covered by the P-type insulating layer 13 on the P-type contact layer 12 .

[0012] According to an embodiment of the present disclosure, the coupling relationship of the ridge waveguide region is:

[0013]

[0014] in, is the Hamiltonian of the waveguide array, For one dimensional tridiagonal matrix, is the number of waveguides in the waveguide array, is an N-dimensional column matrix, is the complex propagation constant of the supermode generated by the waveguide array coupling, and N is a positive integer greater than or equal to 1.

[0015] According to an embodiment of the present disclosure, the Hamiltonian The matrix element of the mth row and nth column of :

[0016]

[0017] in, is the Kronecker-delta symbol, when hour ;when hour , is the coupling coefficient generated when the mode field of the mth waveguide perturbs the mode field of the nth waveguide, is the complex propagation constant of the fundamental mode of the mth waveguide, and m and n are both positive integers greater than or equal to 1.

[0018] According to the embodiment of the present disclosure, the arrangement period of the plurality of quasi-PT-symmetric semiconductor laser tubes 2 is the width of the quasi-PT-symmetric semiconductor laser tube 2 in the horizontal direction.

[0019] According to the embodiment of the present disclosure, the cavity length of the quasi-PT-symmetric semiconductor laser single tube 2 is the length of the quasi-PT-symmetric semiconductor laser single tube 2 in the longitudinal direction.

[0020] According to the embodiment of the present disclosure, the thickness of the N-type waveguide layer 7 is greater than that of the P-type waveguide layer 10 .

[0021] According to the embodiment of the present disclosure, when the electrical injection gain is less than the gain required for PT breaking, the lasing mode of the semiconductor laser stripe based on quasi-PT symmetry is multi-mode lasing;

[0022] When the electrical injection gain is greater than the gain required for PT breaking, the stripe lasing mode of the semiconductor laser based on quasi-PT symmetry is single-side mode lasing.

[0023] A second aspect of the embodiments of the present disclosure provides a spectrum combining device, including:

[0024] A quasi-PT symmetric semiconductor laser bar 16, used to generate laser beams to be combined;

[0025] A first collimator 17, used for fast-axis collimating the laser beam to be combined to obtain a first laser beam;

[0026] A beam converter 18, used to rotate the fast axis and the slow axis of the first laser beam by 90 degrees to obtain a second laser beam;

[0027] A second collimator 19, used for performing slow-axis collimation on the second laser beam to obtain a third laser beam;

[0028] A transmission lens 20, used for converging the third laser beam to obtain a fourth laser beam;

[0029] A zero-order half-wave plate 21, used for changing the polarization state of the fourth laser beam to obtain a fifth laser beam;

[0030] a transmission grating 22, used for selecting laser beams of different wavelengths from the fifth laser beam;

[0031] The output coupling mirror 23 is used to feed back any part of the laser light of different wavelengths to the quasi-PT symmetric semiconductor laser bar 16 to form laser oscillation, and output the laser light of different wavelengths to form stable oscillation light.

[0032] According to the embodiment of the present disclosure, the spectrum of the remaining part of the light has a plurality of closely arranged spectrum peaks, and the number of the spectrum peaks is equal to the number of the quasi-PT-symmetric semiconductor laser single tubes 2 on the quasi-PT-symmetric semiconductor laser bar 16 .

[0033] According to the quasi-PT symmetric semiconductor laser bar and its spectrum combining device provided by the embodiment of the present disclosure, by using the injection current to pump the gain waveguide array and maintaining loss-free current injection, the two work together to form a quasi-PT symmetric distribution of the complex refractive index of the laser in the lateral direction, and continue to apply current to break the PT symmetry state, so as to achieve single-side mode laser output of each single tube. The spectrum combining device uses optical lenses and gratings to combine the independent light emitted by each semiconductor laser on the bar into a beam of light with uniform wavelength distribution, so as to achieve high-power laser output and improve the lateral beam quality of the semiconductor laser bar. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0035] Figure 1 A cross-sectional view of a quasi-PT symmetric semiconductor laser bar provided by an embodiment of the present disclosure is schematically shown;

[0036] Figure 2 A side view of a quasi-PT symmetric semiconductor laser bar provided by an embodiment of the present disclosure is schematically shown;

[0037] Figure 3 A cross-sectional view of a spectrum combining device provided by an embodiment of the present disclosure is schematically shown;

[0038] Figure 4 The far-field distribution diagram of a single quasi-PT symmetric semiconductor laser tube provided by an embodiment of the present disclosure at a current of 0.5 A is schematically shown;

[0039] Figure 5 The far-field distribution diagram of a single quasi-PT symmetric semiconductor laser tube provided by an embodiment of the present disclosure at a current of 1.5 A is schematically shown;

[0040] Figure 6 The schematic diagram shows the laser spot diagram after being combined by the spectral beam combining device in the embodiment of the present disclosure. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0042] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0043] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0044] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0045] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0046] Wide-stripe lasers that achieve high-power output are often accompanied by multi-side mode lasing, resulting in poor beam quality, which limits the further expansion of their application scenarios. Introducing a parity-time (PT) symmetric structure in a strip laser can effectively reduce the lateral mode of the semiconductor laser and achieve single-mode lasing. However, its ridge width is narrow, and it is easy to cause cavity surface catastrophes when working under high current. This results in the output optical power of the PT-symmetric laser being low when achieving single-side mode lasing (usually a few hundred milliwatts), and increasing the injection current will cause the mode characteristics of the laser to be unstable, which is not conducive to application in scenarios with high brightness requirements.

[0047] Therefore, the embodiment of the present disclosure provides a quasi-PT symmetric semiconductor laser bar and a spectral beam combining device. The quasi-PT symmetric semiconductor laser bar includes a plurality of quasi-PT symmetric semiconductor laser tubes 2, the plurality of quasi-PT symmetric semiconductor laser tubes 2 are arranged horizontally and closely, and there is no coupling between the lasers emitted by the plurality of quasi-PT symmetric semiconductor laser tubes 2. The quasi-PT symmetric semiconductor laser tube 2 includes an N-type electrode 4, an N-type substrate layer 5, an N-type waveguide cap layer 6, an N-type waveguide layer 7, an alternatingly distributed barrier layer 8 and a potential well layer 9, a P-type waveguide layer 10, a P-type waveguide cap layer 11, a P-type contact layer 12, a P-type insulating layer 13 and a P-type electrode 14, which are arranged in sequence. Among them, a ridge waveguide region 3 is provided on the P-type waveguide layer 10, the P-type waveguide cap layer 11 and the P-type contact layer 12. The spectral beam combining device is used to spectrally combine the lasers emitted by each quasi-PT symmetric semiconductor laser tube 2 in the semiconductor laser bar based on quasi-PT symmetry to obtain a combined laser output.

[0048] In the above-mentioned quasi-PT-symmetric semiconductor laser bar and spectral beam combining device, the complex refractive index of the laser forms a quasi-PT-symmetric distribution in the lateral direction through the action of the ridge waveguide region 3, and the application of current can break the PT symmetry, thereby realizing the single-side mode laser output of each single tube 2; and the spectral beam combining device combines the independent light emitted by each semiconductor laser on the bar into a beam of light with uniform wavelength distribution through optical lenses and gratings, thereby realizing high-power laser output and improving the lateral light beam quality of the quasi-PT-symmetric semiconductor laser bar.

[0049] The following specific embodiments are listed to illustrate the technical solution of the present disclosure in detail. It should be noted that the following specific embodiments are only used for illustration and are not used to limit the present disclosure.

[0050] Figure 1 FIG. 4 is a cross-sectional view of a quasi-PT symmetric semiconductor laser bar according to an embodiment of the present disclosure.

[0051] like Figure 1As shown, the present disclosure provides a quasi-PT symmetric semiconductor laser bar 1, comprising: an N-type electrode 4 plated on the bottom of an N-type substrate layer 5, for providing an electric injection channel; an N-type substrate layer 5 as a base of an epitaxial layer; an N-type waveguide cap layer 6 disposed between the N-type substrate layer 5 and an N-type waveguide layer 7, for limiting the optical field of the laser; an N-type waveguide layer 7 disposed between the N-type waveguide cap layer 6 and an active region, for expanding the optical field of the laser. The active region arranged between the N-type waveguide layer 7 and the P-type waveguide layer 10 includes alternately distributed barrier layers 8 and potential well layers 9 to form a quantum well region for generating laser gain; the P-type waveguide layer 10 arranged between the active region and the P-type waveguide cap layer 11 is used to expand the optical field of the laser and is etched into a waveguide morphology when the etching depth is deep; the P-type waveguide cap layer 11 arranged between the P-type waveguide layer 10 and the P-type contact layer 12 is used to limit the optical field of the laser and is etched into a waveguide morphology; the P-type contact layer 12 grown on the P-type waveguide cap layer 11 is arranged as a heavily doped layer and is etched into a waveguide morphology; the P-type insulating layer 13 covering the P-type waveguide cap layer 11 and part of the P-type contact layer 12 is made of silicon dioxide; the P-type electrode 14 arranged on the P-type insulating layer 13 and the P-type contact layer 12 is used for the electric injection channel of the laser and forms an ohmic contact with the P-type contact layer 12.

[0052] According to an embodiment of the present disclosure, the quasi-PT symmetric semiconductor laser bar 1 is composed of a quasi-PT symmetric semiconductor laser tube 2, and the ridge waveguide region 3 of the quasi-PT symmetric semiconductor laser tube 2 includes a waveguide array. The distribution of the waveguides in the waveguide array is symmetrical distribution or asymmetrical distribution. The coupling coefficient k between adjacent waveguides is affected by the waveguide width, etching depth, and the spacing between adjacent waveguides.

[0053] The waveguides in the waveguide array include a gain waveguide 31 and a loss waveguide 32. The loss waveguide 32 is represented by the portion of the P-type insulating layer 13 that is completely covered on the P-type contact layer 12, and the complex propagation constant of the fundamental mode of the loss waveguide 32 has a negative imaginary part. The gain waveguide 31 is represented by the portion of the P-type insulating layer 13 that is not completely covered on the P-type contact layer 12, and the current can be injected into the semiconductor laser through the exposed window of the P-type electrode 14, thereby generating gain, and the complex propagation constant of the fundamental mode of the gain waveguide 31 has a positive imaginary part.

[0054] In some embodiments, the number of the gain waveguides 31 in a ridge waveguide region 3 may be one or more, and the number of the loss waveguides 32 may also be one or more, which is not limited in the present disclosure.

[0055] According to an embodiment of the present disclosure, the coupling relationship of the ridge waveguide region 3 satisfies:

[0056]

[0057] in is the Hamiltonian of the waveguide array, expressed as an N×N dimensional tridiagonal matrix, where N is the number of waveguides in the waveguide array. The matrix element of the mth row and nth column can be written as:

[0058]

[0059] in, is the Kronecker-delta symbol, when hour ;when hour , is the coupling coefficient generated when the mode field of the mth waveguide perturbs the mode field of the nth waveguide, is the complex propagation constant of the fundamental mode of the mth waveguide, and m and n are both positive integers greater than or equal to 1.

[0060] in is an N-dimensional column matrix, the mth element represents the electric field amplitude of the mth waveguide; represents the complex propagation constant of the supermode generated by the waveguide array coupling. If there are N waveguides, the coupling relationship is satisfied. There will be N eigenvalues, denoted as form.

[0061] According to an embodiment of the present disclosure, the interval, period number and cavity length 15 of the quasi-PT symmetric semiconductor laser tubes 2 constituting the quasi-PT symmetric semiconductor laser bar 1 can be varied. Specifically, the cavity length of the quasi-PT symmetric semiconductor laser tube 2 is the length of the quasi-PT symmetric semiconductor laser tube 2 in the longitudinal direction. The cavity length of the quasi-PT symmetric semiconductor laser tube 2 is the length of the quasi-PT symmetric semiconductor laser tube 2 in the longitudinal direction. The period number of the quasi-PT symmetric semiconductor laser tube 2 can be the number of periodic arrangements in a quasi-PT symmetric semiconductor laser bar 1. Figure 2 A side view of a quasi-PT symmetric semiconductor laser bar provided by an embodiment of the present disclosure is schematically shown, wherein the number of periods of the bar is only for illustration, and the cavity length 15 of the bar is set to 2 mm.

[0062] According to an embodiment of the present disclosure, the active region between the N-type waveguide layer 7 and the P-type waveguide layer 10 includes: a quantum well or a quantum dot.

[0063] According to the embodiment of the present disclosure, in the light emitting direction z of the quasi-PT symmetric semiconductor laser bar 1, the front cavity surface is required to be coated with an anti-reflection film, and the rear cavity surface is required to be coated with a high-reflection film.

[0064] According to an embodiment of the present disclosure, the pumping method of the quasi-PT symmetric semiconductor laser bar is electrical injection.

[0065] According to the embodiments of the present disclosure, a quasi-PT symmetric semiconductor laser bar and a spectral beam combining device thereof are applied in the field of semiconductor lasers.

[0066] According to the embodiments of the present disclosure, the quasi-PT symmetric semiconductor laser bar is manufactured by using semiconductor processing techniques such as thin film growth, epitaxial growth, exposure, and etching.

[0067] like Figure 1 In the illustrated embodiment, the ridge waveguide region 3 of the quasi-PT symmetric semiconductor laser single tube 2 is configured as a gain waveguide (left side) and a loss waveguide (right side), and the bar strip is configured as a close arrangement of 19 single tubes.

[0068] The lasing wavelength is set to 980 nm, and the active region is set to a double quantum well structure. The thickness of the quantum well barrier layer 8 and the quantum well potential well layer 9 are set to 0.01 and 0.007 ; N-type substrate layer 5 is set to 0.5 , N-type waveguide cover layer 6 is set to 1 ; N-type waveguide layer 7 is set to 4.5 ; The P-type waveguide layer 10 is set to 0.7 , the P-type waveguide cover layer 11 is set to 0.8 , the P-type contact layer 12 is set to 0.2 .

[0069] The P-type insulating layer 13 is made of silicon dioxide with a thickness of 0.25 .

[0070] The N-type electrode 4 and the P-type electrode 14 are made of gold. In order to reduce the smile effect of the bar and facilitate the subsequent spectral beam combining process, the thickness of the electrodes on both sides of the N-type and P-type electrodes is set to 4 .

[0071] Figure 3 A cross-sectional view of a spectrum combining device provided by an embodiment of the present disclosure is schematically shown.

[0072] like Figure 3As shown, the present disclosure provides a spectral beam combining device including: a quasi-PT symmetric semiconductor laser bar 16 for generating a laser beam to be combined; a first collimator 17 for fast-axis collimating the laser beam to be combined to obtain a first laser beam; a beam converter 18 for rotating the fast axis and slow axis of the first laser beam by 90 degrees to obtain a second laser beam; a second collimator 19 for slow-axis collimating the second laser beam to obtain a third laser beam; a transmission lens 20 for converging the third laser beam to obtain a fourth laser beam; a zero-order half-wave plate 21 for changing the polarization state of the fourth laser beam to obtain a fifth laser beam; a transmission grating 22 as a dispersion element for selecting lasers of different wavelengths from the fifth laser beam; an output coupling mirror 23 for feeding back any part of the laser light of different wavelengths to the quasi-PT symmetric semiconductor laser bar 16 to form laser oscillation, and outputting laser light of different wavelengths to form stable oscillation light.

[0073] According to an embodiment of the present disclosure, the N-type waveguide cap layer 6, the N-type waveguide layer 7, the quantum well barrier layer 8, the quantum well potential well layer 9, the P-type waveguide layer 10, the P-type waveguide cap layer 11 and the P-type contact layer 12 are all made of semiconductor materials.

[0074] According to the embodiments of the present disclosure, the doping, composition and thickness of the above-mentioned N-type waveguide cap layer 6, N-type waveguide layer 7, quantum well barrier layer 8, quantum well potential well layer 9, P-type waveguide layer 10, P-type waveguide cap layer 11 and P-type contact layer 12 can be designed according to the required wavelength.

[0075] According to an embodiment of the present disclosure, the optical device of the spectrum beam combining device can be selected according to the wavelength of the laser light emitted by the quasi-PT symmetric semiconductor laser bar 16 .

[0076] In one embodiment, the size of the beam converter 18 is designed to match the bar period, the rotation angle of the zero-order half-wave plate 21 is designed to be able to convert the P wave emitted by the laser into an S wave, the transmittance of the transmission grating 22 is designed to be 98% for S waves in the 980 nm band, and the remaining optical components are coated with an anti-reflection film in the 980 nm band.

[0077] Figure 4 The far-field distribution diagram of a single quasi-PT symmetric semiconductor laser tube provided by an embodiment of the present disclosure at a current of 0.5 A is schematically shown.

[0078] like Figure 4 According to the embodiment of the present disclosure, the injected current is the gain applied to the laser. When the gain is small, the laser is in a PT symmetric state, the real part of the supermode is split and the imaginary part is degenerate, resulting in the output laser being a double-lobe far field.

[0079] Figure 5The far-field distribution diagram of a single quasi-PT symmetric semiconductor laser tube provided by an embodiment of the present disclosure at a current of 1.5 A is schematically shown.

[0080] like Figure 5 As shown, the far field of the laser presents a single-lobe distribution. According to the embodiment of the present disclosure, the injected current is the gain applied to the laser. When the gain is large, the laser is in a PT symmetry-breaking state, at which time the real part of the supermode is degenerate and the imaginary part is split, resulting in a part of the output laser being emitted in the gain waveguide and the other part being lost in the loss waveguide, thereby outputting a single-lobe far field.

[0081] Figure 6 The schematic diagram shows the laser spot diagram after the laser beam is combined by the spectral beam combining device in the embodiment of the present disclosure. When the PT symmetry is broken by the injected current, the spot after the beam is combined is a single lobe.

[0082] According to the above-mentioned embodiments of the present disclosure, in the quasi-PT symmetric semiconductor laser bar and its spectrum combining device, the gain waveguide array and the loss waveguide array on the quasi-PT symmetric semiconductor laser single tube work together to make the complex refractive index of the laser form a quasi-PT symmetric distribution in the lateral direction, and the current is applied to introduce the gain. When the injected current reaches a certain level, the PT symmetry state can be broken, and the single-side mode laser output of each single tube can be achieved. And through the spectrum combining device provided by the present disclosure, the independent light emitted by each semiconductor laser on the bar is combined into a beam of light with uniform wavelength distribution by using optical lenses and gratings, so as to achieve high-power laser output and improve the lateral beam quality of the semiconductor laser bar, so that the quasi-PT symmetric semiconductor laser bar can be further applied to the use scenarios requiring high power and high beam quality.

[0083] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A semiconductor laser bar based on quasi-PT symmetry, characterized in that: Comprising a plurality of quasi-PT symmetric semiconductor laser single tubes (2), wherein the plurality of quasi-PT symmetric semiconductor laser single tubes (2) are closely arranged horizontally, and there is no coupling between the lasers emitted by the plurality of quasi-PT symmetric semiconductor laser single tubes (2); The quasi-PT symmetric semiconductor laser single tube (2) comprises an N-type electrode (4), an N-type substrate layer (5), an N-type waveguide cover layer (6), an N-type waveguide layer (7), alternately distributed potential barrier layers (8) and potential well layers (9), a P-type waveguide layer (10), a P-type waveguide cover layer (11), a P-type contact layer (12), a P-type insulating layer (13) and a P-type electrode (14) which are arranged in sequence; Wherein, a ridge waveguide region (3) is provided on the P-type waveguide layer (10), the P-type waveguide cover layer (11) and the P-type contact layer (12).

2. The semiconductor laser bar based on quasi-PT symmetry according to claim 1, characterized in that: The ridge waveguide region (3) comprises a waveguide array, and the waveguides in the waveguide array are distributed in a symmetrical distribution or an asymmetrical distribution; The waveguides in the waveguide array include a gain waveguide (31) and a loss waveguide (32); The gain waveguide (31) is a portion of the P-type insulating layer (13) that is not completely covered on the P-type contact layer (12); The lossy waveguide (32) is the portion of the P-type insulating layer (13) that completely covers the P-type contact layer (12).

3. The semiconductor laser bar based on quasi-PT symmetry according to claim 1, characterized in that: The coupling relationship of the ridge waveguide region (3) is: in, is the Hamiltonian of the waveguide array, For one dimensional tridiagonal matrix, is the number of waveguides in the waveguide array, is an N-dimensional column matrix, is the complex propagation constant of the supermode generated by the waveguide array coupling, and N is a positive integer greater than or equal to 1.

4. The semiconductor laser bar based on quasi-PT symmetry according to claim 3, characterized in that: The Hamiltonian The matrix element of the mth row and nth column is: in, is the Kronecker-delta symbol, when hour ;when hour , is the coupling coefficient generated when the mode field of the mth waveguide perturbs the mode field of the nth waveguide, is the complex propagation constant of the fundamental mode of the mth waveguide, and m and n are both positive integers greater than or equal to 1.

5. The semiconductor laser bar based on quasi-PT symmetry according to claim 1, characterized in that: The arrangement period of the plurality of quasi-PT symmetric semiconductor laser tubes (2) is the width of the quasi-PT symmetric semiconductor laser tube (2) in the horizontal direction.

6. The semiconductor laser bar based on quasi-PT symmetry according to claim 1, characterized in that: The cavity length of the quasi-PT symmetric semiconductor laser single tube (2) is the length of the quasi-PT symmetric semiconductor laser single tube (2) in the longitudinal direction.

7. The semiconductor laser bar based on quasi-PT symmetry according to claim 1, characterized in that: The N-type waveguide layer (7) is thicker than the P-type waveguide layer (10).

8. The semiconductor laser bar based on quasi-PT symmetry according to claim 1, characterized in that: When the electrical injection gain is less than the gain required for PT breaking, the lasing mode of the semiconductor laser stripe based on quasi-PT symmetry is multi-mode lasing; When the electrical injection gain is greater than the gain required for PT breaking, the stripe lasing mode of the semiconductor laser based on quasi-PT symmetry is single-side mode lasing.

9. A spectrum combining device, characterized in that: include: A quasi-PT symmetric semiconductor laser bar (16) for generating a laser beam to be combined; A first collimator (17) is used to perform fast-axis collimation on the laser beam to be combined to obtain a first laser beam; A beam converter (18), used for rotating the fast axis and the slow axis of the first laser beam by 90 degrees to obtain a second laser beam; A second collimator (19) is used to perform slow-axis collimation on the second laser beam to obtain a third laser beam; A transmission lens (20) is used to converge the third laser beam to obtain a fourth laser beam; A zero-order half-wave plate (21), used for changing the polarization state of the fourth laser beam to obtain a fifth laser beam; A transmission grating (22), used for selecting laser light of different wavelengths from the fifth laser light beam; The output coupling mirror (23) is used to feed back any part of the laser light of different wavelengths to the quasi-PT symmetric semiconductor laser bar (16) to form laser oscillation, and output the laser light of different wavelengths to form stable oscillation light.

10. The spectral beam combining device according to claim 9, characterized in that: The spectrum of the light after stable oscillation has a plurality of closely arranged spectrum peaks, and the number of the spectrum peaks is equal to the number of quasi-PT-symmetric semiconductor laser single tubes (2) on the quasi-PT-symmetric semiconductor laser bar (16).

Images