External cavity wave locking semiconductor laser and adjusting method thereof

Abstract

The invention provides an external cavity wave locking semiconductor laser and an adjusting method thereof, and relates to the technical field of laser. The semiconductor laser provided by the embodiment of the invention comprises a first chipset configured to emit S light; a second chip group configured to emit P light; the first reflecting element is configured to reflect the S light to a first side of the polarization beam combining module; the P light is projected to the polarization beam combining module from the second side of the polarization beam combining module; the first side is opposite to the second side; the second reflecting element is located on the second side of the polarization beam combining module and located on the side, away from the first reflecting element, of the polarization beam combining module, and the second reflecting element partially reflects light and partially transmits light and is used for conducting external cavity wave locking on the semiconductor laser. According to the embodiment of the invention, power loss in an optical path is not increased while external cavity wave locking is carried out on the semiconductor laser.

Description

Technical Field

[0001] The invention relates to the field of laser technology, and in particular to an external cavity-locked semiconductor laser and an adjustment method thereof. Background Art

[0002] Semiconductor lasers have excellent characteristics such as high efficiency, compact structure, wide wavelength range, low cost, and high reliability. As pump sources, they are widely used in fiber lasers. However, semiconductor lasers have a disadvantage as pump sources. When the temperature rises, the laser wavelength will redshift.

[0003] At present, in order to reduce the impact of the red shift of semiconductor lasers on the laser wavelength, a common practice is to place a volume Bragg grating in the original optical path of the fiber laser to achieve the selection of the longitudinal mode. However, adding a volume Bragg grating to the fiber laser will increase the loss of the optical path, resulting in a decrease in the efficiency of the fiber laser. Summary of the invention

[0004] The embodiment of the present invention provides an external cavity-locked semiconductor laser and an adjustment method thereof, which can realize external cavity-locking of the semiconductor laser without increasing the power loss of the laser.

[0005] An embodiment of the present invention provides an external cavity-locked semiconductor laser, comprising:

[0006] A first chipset is configured to emit S light;

[0007] A second chip group is configured to emit P light, and the first chip group and the second chip group both include a plurality of laser diodes;

[0008] A first reflecting element and a polarization beam combining module, wherein the first reflecting element is located on an optical path between the first chipset and the polarization beam combining module, and is configured to reflect the S light to a first side of the polarization beam combining module; the P light is projected from a second side of the polarization beam combining module to the polarization beam combining module; the first side is opposite to the second side;

[0009] The second reflective element is located at the second side of the polarization beam combining module and at the side of the polarization beam combining module away from the first reflective element. The second reflective element partially reflects light and partially transmits light, and is used to perform external cavity wave locking on the semiconductor laser.

[0010] Optionally, both the first chipset and the second chipset include a plurality of spot shaping elements and a plurality of first reflectors, the spot shaping element is located between the laser diode and the first reflector, the first reflector in the first chipset is located on the optical path between the spot shaping element and the first reflector, and the first reflector in the second chipset is located on the optical path between the spot shaping element and the polarization beam combining module.

[0011] Optionally, the second chipset further includes a half-wave plate, which is located on the optical path between the first reflector and the polarization beam combining module and is configured to convert the S light into P light.

[0012] Optionally, the semiconductor laser further includes a beam focusing module, and the beam focusing module is located on a first side of the polarization beam combining module and on a reflection light path of the polarization beam combining module.

[0013] Optionally, the second reflective element comprises a reflective volume Bragg grating.

[0014] Optionally, the second reflective element comprises a reflective narrow bandwidth filter.

[0015] Optionally, the front cavity reflectivity of the laser diode is A, the polarization efficiency of the laser diode is B, and the reflectivity of the second reflective element is C, satisfying:

[0016] C×(1-B)×(1-A)>A.

[0017] Optionally, the second reflective element can be removed from the semiconductor laser after completing wave locking.

[0018] In a second aspect, an embodiment of the present invention provides a method for adjusting a semiconductor laser based on the first aspect, comprising the following steps:

[0019] The first reflector is set by adjusting one of the first chipset or the second chipset so that the light coupling efficiency corresponding to the first reflector meets the preset coupling condition, and the first reflector is fixedly set.

[0020] Optionally, the adjustment method further includes:

[0021] According to the first spectrum data received by the spectrometer, the second reflective element is adjusted so that the initial longitudinal mode disappears and the new longitudinal mode is stable;

[0022] According to the preset adjustment conditions, the first reflector other than the set first reflector in the first chipset or the second chipset is adjusted; wherein the preset adjustment conditions include the second spectrum data received by the spectrometer, so that the second spectrum data is consistent with the first spectrum data.

[0023] Optionally, the preset adjustment condition also includes optical power, so that the optical power is maximized.

[0024] Optionally, after adjusting the first reflector other than the first reflector in the first chipset or the second chipset according to the preset adjustment condition, the method further includes:

[0025] The second reflective element is removed from the semiconductor laser.

[0026] The semiconductor laser provided by the embodiment of the present invention reflects the P-polarized stray light and the S-polarized stray light leaked from the polarization beam combining module back into the optical path of the semiconductor laser by setting a second reflecting element, and makes the central longitudinal mode of the P-polarized stray light and the S-polarized stray light oscillate between the cavity mirror and the second reflecting element, so that the first chip group and the second chip group are stimulated to radiate the same central longitudinal mode, suppress other longitudinal modes, realize external cavity locking, and improve the monochromaticity of the semiconductor laser; reducing the number of longitudinal modes also makes the divergence angle of the polarization beam combining light smaller, so as to reduce the numerical aperture of the semiconductor laser; setting the second reflecting element on the second side of the polarization beam combining module does not affect the luminous efficiency of the semiconductor laser, and does not increase the power loss of the laser while improving the monochromaticity of the semiconductor laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic structural diagram of an external cavity-locked semiconductor laser provided by an embodiment of the present invention;

[0028] Figure 2 is a schematic structural diagram of another external cavity-locked semiconductor laser provided by an embodiment of the present invention;

[0029] Figure 3 It is a schematic structural diagram of another external cavity-locked semiconductor laser provided by an embodiment of the present invention;

[0030] Figure 4 It is a schematic structural diagram of another external cavity-locked semiconductor laser provided by an embodiment of the present invention;

[0031] Figure 5 It is a flow chart of the adjustment steps of an external cavity-locked semiconductor laser provided by an embodiment of the present invention;

[0032] Figure 6 A fiber laser is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] The embodiment of the present invention provides a semiconductor laser with external cavity locking, referring to Figure 1, the semiconductor laser includes a first chipset 110, a first reflective element 130 and a polarization beam combining module 140. The first chipset 110 is configured to emit S light. The second chipset 120 is configured to emit P light. The first chipset 110 and the second chipset 120 each include a plurality of laser diodes. The embodiment of the present invention does not specifically limit the number of laser diodes. The first reflective element 130 is located on the optical path between the first chipset 110 and the polarization beam combining module 140, and the first reflective element 130 is configured to reflect the S light to the first side of the polarization beam combining module 140. The P light is projected from the second side of the polarization beam combining module 140 to the polarization beam combining module 140. The first side of the polarization beam combining module 140 is opposite to the second side of the polarization beam combining module 140. The second reflective element 150 is located on the second side of the polarization beam combining module 140 and on the side of the polarization beam combining module 140 away from the first reflective element 130. The second reflective element 150 partially reflects the light and partially transmits the light, and is used to perform external cavity locking on the semiconductor laser.

[0035] The polarization beam combining module 140 is configured to reflect S light and transmit P light. The S light 101 emitted by the first chipset 110 is reflected by the first reflective element 130 and then reflected by the polarization beam combining module 140. The P light 102 emitted by the second chipset 120 transmits through the polarization beam combining module 140 and then combines with the S light reflected by the polarization beam combining module 140 to form a polarization beam combining light beam 103.

[0036] Due to the inherent characteristics of the laser diode, a small amount of P-polarized stray light will exist in the S light 101 emitted by the first chipset 110, and a small amount of S-polarized stray light will exist in the P light 102 emitted by the second chipset 120. After the S light 101 emitted by the first chipset is reflected by the first reflective element 130 and incident on the polarization beam combining module 140, a small amount of P-polarized stray light in the S light 101 emitted by the first chipset will pass through the polarization beam combining module 140, and then the P-polarized stray light will be partially reflected by the second reflective element 150 and return to the polarization beam combining module 140, and the P-polarized stray light will pass through the polarization beam combining module 140 and propagate in the reverse direction along its original propagation path, and finally return to the resonant cavity of the laser diode in the first chipset 110. In the resonant cavity, the P-polarized stray light will be reflected by the rear cavity mirror of the laser diode, where the rear cavity mirror is a cavity mirror far away from the light-emitting surface, and will be emitted again from the first chipset 110, and will propagate back and forth between the rear cavity mirror and the second reflective element 150, thereby forming a first resonant cavity by the rear cavity mirror of the laser diode in the first chipset 110 and the second reflective element 150. Due to the characteristics of the laser diode, the light beam emitted by the laser diode contains multiple longitudinal modes, and only the longitudinal modes that meet the resonance conditions of the first resonant cavity in the P-polarized stray light will oscillate in the first resonant cavity, and the longitudinal modes that do not meet the resonance conditions of the first resonant cavity in the P-polarized stray light will be suppressed. Therefore, the position of the second reflective element 150 can be adjusted so that the longitudinal mode of a specific wavelength in the P-polarized stray light meets the resonance conditions of the first resonant cavity, and the longitudinal mode of a specific wavelength that meets the resonance conditions of the first resonant cavity is the central longitudinal mode. The central longitudinal mode will increase in intensity during oscillation, and other longitudinal modes will be suppressed or even disappear in mode competition. The gain medium of the laser diode in the first chipset group 110 is affected by the central longitudinal mode and stimulated to radiate laser light of the same longitudinal mode, so that the intensity of the central longitudinal mode in the light beam emitted by the first chipset group 110 is increased and other longitudinal modes are suppressed.

[0037] Similarly, when the P light 102 emitted by the second chipset is incident on the polarization beam combining module 140, a small amount of S-polarized stray light in the P light 102 emitted by the second chipset will be reflected by the polarization beam combining module 140. After being reflected by the second reflective element 150, the reflected S-polarized stray light will also propagate in the opposite direction along the original propagation path into the resonant cavity of the laser diode in the second chipset 120. After being reflected by the rear cavity mirror of the laser diode in the second chipset 120, the S-polarized stray light will propagate back and forth between the rear cavity mirror of the laser diode in the second chipset 120 and the second reflective element 150. Thus, the rear cavity mirror of the laser diode in the second chipset 120 and the second reflective element 150 form a second resonant cavity, and the longitudinal mode in the S-polarized stray light that meets the resonant condition of the second resonant cavity will oscillate in the second resonant cavity, and the longitudinal mode in the S-polarized stray light that does not meet the resonant condition of the second resonant cavity will be suppressed or even disappear. As a result, the second chipset 120 will be stimulated to radiate the longitudinal mode that meets the resonance condition of the second resonant cavity, so that the intensity of the longitudinal mode that meets the resonance condition of the second resonant cavity in the light beam emitted by the second chipset 120 increases, and other longitudinal modes are suppressed. The narrow line width light reflected by the second reflective element 150 returns to the resonant cavity of the laser diode, driving the narrow line width light of the laser diode to achieve external cavity locking.

[0038] In addition, each longitudinal mode has a divergence angle, and the propagation direction of each longitudinal mode is also different, so the more longitudinal modes the light beam contains, the greater the overall divergence angle of the light beam, and the worse the directivity of the light beam. The first resonant cavity and the second resonant cavity formed by the second reflective element 150 and the rear cavity mirror suppress some longitudinal modes, thereby reducing the longitudinal modes contained in the polarization combined beam 103, improving the directivity of the polarization combined beam 103, and reducing the divergence angle of the polarization combined beam 103, that is, reducing the numerical aperture of the semiconductor laser.

[0039] The semiconductor laser provided in the embodiment of the present invention reflects the P-polarized stray light and S-polarized stray light leaked from the polarization beam combining module back into the optical path of the semiconductor laser by setting a second reflective element, and makes the central longitudinal mode of the P-polarized stray light and the S-polarized stray light oscillate between the rear cavity mirror and the second reflective element, so that the first chip group and the second chip group stimulate radiation of the same central longitudinal mode, suppress other longitudinal modes emitted by the laser diode, achieve wavelength locking, and improve the monochromaticity of the semiconductor laser; reducing the number of longitudinal modes also reduces the divergence angle of the polarization beam combining light, thereby reducing the numerical aperture of the semiconductor laser; setting the second reflective element on the second side of the polarization beam combining module does not affect the luminous efficiency of the semiconductor laser, and keeps the optical power of the semiconductor laser unchanged while improving the monochromaticity of the semiconductor laser. In the embodiment of the present invention, the second reflective element is set at the light leakage position of the polarization beam combining module, and the light that would have been lost is used to achieve external cavity wave locking.

[0040] Figure 2is a schematic diagram of the structure of an embodiment of an external cavity-locked semiconductor laser provided by the present invention, with reference to Figure 2 , the first chipset 110 and the second chipset 120 both include a plurality of spot shaping elements 112 and a plurality of first reflectors 113, the spot shaping element 112 is located between the laser diode 111 and the first reflector 113, and the first reflector 113 in the first chipset 110 is located on the optical path between the spot shaping element 112 and the first reflector 130. The first reflector 113 in the second chipset 120 is located on the optical path between the spot shaping element 112 and the polarization beam combining module 140. The embodiment of the present invention does not specifically limit the number of the spot shaping elements 112 and the first reflector 113.

[0041] refer to Figure 2 , the laser beam emitted by the laser diode 111 is modulated by the light spot shaping element 112 to become a parallel beam. The multiple first reflectors 113 are arranged in steps, so that the first reflectors 113 will not block the parallel beams reflected by other first reflectors 113. The first reflectors 113 can reflect the parallel beams emitted from the light spot shaping element 112. In the first chipset 110, the beams reflected by the first reflectors 113 are finally combined into S light 101, and in the second chipset 120, the beams reflected by the first reflectors 113 are finally combined into P light 102.

[0042] Exemplarily, the light spot shaping element 112 includes a fast-axis collimating lens and a slow-axis collimating lens, wherein the fast-axis collimating lens is located between the laser diode and the slow-axis collimating lens, and the slow-axis collimating lens is located between the fast-axis collimating lens and the first reflector 113 .

[0043] Figure 3 FIG. 1 is a schematic diagram of a structure of another external cavity-locked semiconductor laser provided by an embodiment of the present invention, referring to FIG. Figure 3 The second chipset 120 further includes a half-wave plate 121, which is located on the optical path between the first reflector 113 and the polarization beam combining module 140 and is configured to convert the S light into the P light. The optical axis direction of the half-wave plate 121 is set to be at an angle of 45° with the polarization direction of the S light. The laser diode 111 in the second chipset 120 emits the S light, which is combined after passing through the spot shaping element 112 and the first reflector 113, and then converted into the P light 102 after passing through the half-wave plate 121. The P light 102 is transmitted through the polarization beam combining module 140 and finally combined with the S light 101 emitted by the first chipset 110.

[0044] Figure 4 FIG. 1 is a schematic diagram of a structure of another external cavity-locked semiconductor laser provided by an embodiment of the present invention, referring to FIG. Figure 4The semiconductor laser further includes a beam focusing module 160, which is located at a first side of the polarization beam combining module 140 and at a reflection light path of the polarization beam combining module 140. The beam focusing module 160 is used to focus the polarization beam combining light beam 103, so that the energy of the polarization beam combining light beam 103 is more concentrated and is easier to couple into the coupling optical fiber.

[0045] Exemplarily, the beam focusing module 160 includes a fast axis coupling lens and a slow axis coupling lens, which are located at a first side of the polarization beam combining module 140. The fast axis coupling lens is located between the polarization beam combining module 140 and the slow axis coupling lens.

[0046] Optionally, the second reflective element 150 includes a reflective volume Bragg grating. When the P-polarized stray light and the S-polarized stray light are incident on the reflective volume Bragg grating, diffraction will occur, and the propagation direction of the longitudinal mode of the P-polarized stray light and the S-polarized stray light whose wavelength satisfies the Bragg diffraction law will be deflected by 180°, thereby being reflected by the reflective volume Bragg grating.

[0047] Optionally, the second reflective element 150 comprises a reflective narrow bandwidth filter. Exemplarily, the reflective narrow bandwidth filter is a mirror with a reflectivity of 90%.

[0048] Optionally, the front cavity reflectivity of the laser diode 111 is A, the polarization efficiency of the laser diode 111 is B, and the reflectivity of the second reflective element is C, satisfying: C×(1-B)×(1-A)>A.

[0049] Among them, the front cavity reflectivity refers to the reflectivity of the front cavity mirror. Here, the front cavity mirror is the cavity mirror close to the light-emitting surface of the laser diode 111. The front cavity reflectivity represents the ratio of the light intensity reflected by the front cavity mirror to the total light intensity emitted by the laser diode 111. The reflectivities of the cavity mirrors of all laser diodes 111 in the first chipset 110 and the second chipset 120 of the same batch can be regarded as the same. Then, the ratio of the total light intensity reflected by all front cavity mirrors to the total light intensity emitted by all laser diodes 111 is also equal to the front cavity reflectivity. The polarization efficiency of the laser diode 111 refers to the ratio of the intensity of the S light emitted by the laser diode 111 to the total light intensity emitted by the laser diode 111. Then (1-B)×(1-A) is the ratio of the intensity of the P light emitted by the laser diodes 111 in the first chipset 110 and the second chipset 120 to the total light intensity emitted by the laser diodes 111. The P light emitted by the laser diodes 111 in the first chipset 110 and the second chipset 120 will eventually be incident on the second reflective element 150 in the form of P polarized stray light and S polarized stray light. (1-B)×(1-A) is the ratio of the intensity of the P polarized stray light and the S polarized stray light leaked from the second side of the polarization beam combining module 140 to the total light intensity of the light intensity emitted by all the laser diodes 111 superimposed together. C×(1-B)×(1-A) represents the ratio of the light intensity reflected back by the second reflective element 150 to the total light intensity emitted by all the laser diodes 111. The first resonant cavity is composed of the back cavity mirror of the first chipset group 110 and the second reflective element 150, the second resonant cavity is composed of the back cavity mirror of the second chipset group 120 and the second reflective element 150, and the resonant cavity of the laser diode 111 is composed of the front cavity mirror and the back cavity mirror. The reflectivity of the first resonant cavity, the second resonant cavity and the back cavity mirror of the laser diode 111 is the same, and the ratio of the intensity of the light reflected back by the second reflective element 150 to the total intensity of the light emitted by all the laser diodes 111 is greater than the ratio of the intensity of the light reflected by the front cavity of the laser diode 111 to the total intensity of the light emitted by all the laser diodes 111. That is to say, the intensity of the longitudinal mode oscillating in the first resonant cavity is greater than the total intensity of the longitudinal modes oscillating in the resonant cavities of all the laser diodes 111 in the first chipset group 110, and the intensity of the longitudinal mode oscillating in the second resonant cavity is greater than the total intensity of the longitudinal modes oscillating in the resonant cavities of all the laser diodes 111 in the second chipset group 120. Due to mode competition, the intensity of the central longitudinal mode oscillating in the first resonant cavity and the second resonant cavity will be strengthened, and other longitudinal modes oscillating in the resonant cavity of the laser diode 111 will be suppressed, thereby achieving wavelength locking and reducing the numerical aperture of the semiconductor laser.

[0050] It can be understood that after wave locking is completed, the second reflective element can be removed from the semiconductor laser to reduce manufacturing costs.

[0051] Based on the same inventive concept, an embodiment of the present invention provides an adjustment step of a semiconductor laser provided by an embodiment of the present invention.

[0052] Figure 5 is a flow chart of the adjustment steps of an external cavity-locked semiconductor laser provided by an embodiment of the present invention, with reference to Figure 5 , the adjustment steps of the semiconductor laser include:

[0053] S101, adjusting a first reflector in the first chipset or the second chipset so that the light coupling efficiency corresponding to the first reflector meets a preset coupling condition, and fixing the first reflector.

[0054] Optionally, the first reflector is set to be the first reflector 113 closest to the polarization beam combining module 140. The preset coupling condition includes the laser power received by the spectrometer. The first reflector is adjusted and set so that the laser power received by the spectrometer meets the preset coupling condition.

[0055] S102. According to the first spectrum data received by the spectrometer, adjust the second reflective element so that the initial longitudinal mode disappears and the new longitudinal mode is stable.

[0056] The first spectrum data includes wavelength, intensity, peak value and spectral line shape. The second reflective unit is adjusted so that the conditions of the first resonant cavity and the second resonant cavity meet the resonant conditions of the new longitudinal mode, so that the initial longitudinal mode emitted by the laser diode 111 is suppressed and the new longitudinal mode is stable. The initial longitudinal mode includes the new longitudinal mode, and the second reflective element 150 can select the new longitudinal mode of a specific wavelength.

[0057] S103, adjusting the first reflector other than the first reflector in the first chipset or the second chipset according to a preset adjustment condition; wherein the preset adjustment condition includes second spectrum data received by the spectrometer, so that the second spectrum data is consistent with the first spectrum data.

[0058] The first spectral data includes spectral data received by the spectrometer after the initial longitudinal mode disappears and the new longitudinal mode is stabilized. The first reflector 113 other than the first reflector in the first chipset 110 or the second chipset 120 is adjusted so that the new longitudinal mode emitted by the laser diode 111 is coupled into the polarization beam combining module 140 for beam combining. The beam directivities of different longitudinal modes are different. When the angle of the first reflector 113 is adjusted to allow the beam of the new longitudinal mode to be incident on the polarization beam combining module 140 for beam combining, the beam of the initial longitudinal mode cannot be incident on the polarization beam combining module 140 for beam combining with the new longitudinal mode. At the same time, the second spectral data should be consistent with the first spectral data, that is, the new longitudinal mode is stable, and the initial longitudinal mode is suppressed or even disappears.

[0059] Optionally, the preset adjustment condition also includes optical power, so that the optical power is maximized.

[0060] The first reflector 113 other than the set first reflector in the first chipset 110 or the second chipset 120 is adjusted so that the light beam emitted by the laser diode 111 is coupled into the polarization beam combining module 140 as much as possible and the light beam power output by the semiconductor laser is as large as possible.

[0061] Optionally, after adjusting the first reflector 1113 in the first chipset 110 or the second chipset 120 except for setting the first reflector according to the preset adjustment condition, the method further includes: removing the second reflective element 150. Alternatively, the second reflective element 150 is placed in the semiconductor laser, and the second reflective element 150 is placed at a position outside the reflection light path of the first reflective element 130. Thus, the reflected light of the first reflective element 130 will not be projected onto the second reflective element 150.

[0062] After all the first reflectors 113 are adjusted, the new longitudinal mode can be incident on the polarization beam combining module 140 for beam combining, while the beam of the initial longitudinal mode cannot be incident on the polarization beam combining module 140 for beam combining with the new longitudinal mode. At this time, the second reflective element 150 can be removed from the semiconductor laser, and the semiconductor laser will only output the new longitudinal mode, but not the initial longitudinal mode.

[0063] The semiconductor laser adjustment step provided in the embodiment of the present invention stabilizes the new longitudinal mode of a specific wavelength and suppresses the initial longitudinal mode by adjusting the second reflecting element, thereby reducing the number of longitudinal modes, achieving wavelength locking, and improving the monochromaticity of the semiconductor laser; reducing the number of longitudinal modes also reduces the divergence angle of the polarization combined light beam, thereby reducing the numerical aperture of the semiconductor laser.

[0064] Based on the same inventive concept, an embodiment of the present invention provides a fiber laser, including the semiconductor laser provided by any embodiment of the present invention, wherein the semiconductor laser is used as a pump source.

[0065] Figure 6 is a fiber laser provided by an embodiment of the present invention, referring to Figure 6 The polarized combined beam 103 emitted by the semiconductor laser 100 is coupled into the optical fiber 170 and then output from the optical fiber 170. The optical fiber laser provided by the embodiment of the present invention can reduce the line width of the output beam without affecting the power of the output beam and improve the monochromaticity of the output beam.

[0066] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An external cavity-locked semiconductor laser, characterized in that: include: A first chipset is configured to emit S light; A second chipset is configured to emit P light, wherein the first chipset and the second chipset each include a plurality of laser diodes; a first reflecting element and a polarization beam combining module, wherein the first reflecting element is located on an optical path between the first chipset and the polarization beam combining module and is configured to reflect the S light to a first side of the polarization beam combining module; The P light is projected to the polarization beam combining module from the second side of the polarization beam combining module; the first side is opposite to the second side; The second reflective element is located at the second side of the polarization beam combining module and at the side of the polarization beam combining module away from the first reflective element. The second reflective element partially reflects light and partially transmits light, and is used to perform external cavity locking on the semiconductor laser.

2. The semiconductor laser according to claim 1, characterized in that The first chipset and the second chipset both include a plurality of spot shaping elements, wherein the spot shaping elements are located between the laser diode and the first reflector. In the first chipset, the first reflector is located on an optical path between the spot shaping element and the first reflective element, and in the second chipset, the first reflector is located on an optical path between the spot shaping element and the polarization beam combining module.

3. The semiconductor laser according to claim 2, characterized in that The second chipset further includes a half-wave plate, which is located on the optical path between the first reflector and the polarization beam combining module and is configured to convert the S light into the P light.

4. The semiconductor laser according to claim 1, characterized in that It also includes a beam focusing module, which is located on the first side of the polarization beam combining module and on the reflection light path of the polarization beam combining module.

5. The semiconductor laser according to claim 1, characterized in that The second reflective element includes a reflective volume Bragg grating or a reflective narrow bandwidth filter.

6. The semiconductor laser according to claim 1, characterized in that The front cavity reflectivity of the laser diode is A, the polarization efficiency of the laser diode is B, and the reflectivity of the second reflective element is C, which satisfies: C×(1-B)×(1-A)>A.

7. The semiconductor laser according to claim 1, characterized in that The second reflective element can be removed from the semiconductor laser after wave locking is completed.

8. A method for adjusting a semiconductor laser, characterized in that: The following steps are involved: Adjusting a set first reflector in the first chipset or the second chipset so that the light-to-light coupling efficiency corresponding to the set first reflector meets a preset coupling condition, and fixing the set first reflector; According to the first spectrum data received by the spectrometer, the second reflective element is adjusted so that the initial longitudinal mode disappears and the new longitudinal mode is stable; According to preset adjustment conditions, the first reflector other than the set first reflector in the first chipset or the second chipset is adjusted; wherein the preset adjustment conditions include second spectral data received by the spectrometer, so that the second spectral data is consistent with the first spectral data.

9. The adjustment method according to claim 8, characterized in that: The preset adjustment condition also includes optical power, so that the optical power is maximized.

10. The adjustment method according to claim 8, characterized in that: After adjusting the first reflector other than the set first reflector in the first chipset or the second chipset according to the preset adjustment condition, the method further includes: removing the second reflective element from the semiconductor laser.

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