Detection system and detection method

Abstract

The present invention provides a detection system and a detection method, wherein the detection system comprises: a beam splitter; a semiconductor laser located on a first side of the beam splitter, the semiconductor laser being suitable for outputting a laser beam; a collimating assembly, a first aperture and a second aperture arranged in sequence in an optical path from the semiconductor laser to the beam splitter; a reflector group located on a second side of the beam splitter, the reflector group comprising a reflector; a beam analyzer located on a third side of the beam splitter; a focusing mirror located between the beam analyzer and the beam splitter; a baffle switch used to be located between the reflector group and the beam splitter; the beam splitter is used to transmit part of the laser beam to the beam analyzer and reflect part of the laser beam to the reflector when the baffle switch is turned on; and the reflector is used to reflect the laser beam back to the semiconductor laser along the original optical path when the baffle switch is turned on. The detection system accurately detects the reliability of the semiconductor laser.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor testing, and in particular to a detection system and a detection method. Background Art

[0002] Semiconductor lasers have significant advantages in terms of efficiency, volume, life, and integration, and have great application prospects in the civil, industrial, and military fields. Before being used, semiconductor lasers are characterized and tested for their performance, such as noise, spectrum, optical power, far field, near field, and life test. Semiconductor lasers undergo reliability tests before use. During the reliability test, part of the output light is fed back into the semiconductor laser, causing catastrophic optical damage to the cavity surface of the semiconductor laser, and causing defects in the active area of ​​the semiconductor laser, resulting in irreversible damage.

[0003] Therefore, how to provide a detection system for reliability verification of cavity mask system and active area defects is particularly important for improving the reliability of semiconductor lasers and is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is how to accurately detect the reliability of a semiconductor laser, thereby providing a detection system and a detection method.

[0005] The present invention provides a detection system, comprising: a beam splitter; a semiconductor laser located on a first side of the beam splitter, the semiconductor laser being suitable for outputting a laser beam; a collimating component, a first aperture and a second aperture arranged in sequence in an optical path from the semiconductor laser to the beam splitter; a reflector group located on a second side of the beam splitter, the reflector group comprising a reflector; a beam analyzer located on a third side of the beam splitter; a focusing mirror located between the beam analyzer and the beam splitter; a baffle switch used to be located between the reflector group and the beam splitter; wherein the beam splitter is used to transmit part of the laser beam to the beam analyzer and reflect part of the laser beam to the reflector when the baffle switch is turned on; and the reflector is used to reflect the laser beam back to the semiconductor laser along the original optical path when the baffle switch is turned on.

[0006] Optionally, the focusing mirror is placed within the Rayleigh interval of the collimating component on a side away from the semiconductor laser.

[0007] Optionally, the reflector group includes a support plate and a plurality of the reflectors fixed to the support plate, and the plurality of the reflectors are arranged circumferentially around the central axis of the support plate; at least a part of the reflectors have different reflectivities; the detection system also includes a first adjustment member, which is used to drive the support plate to rotate around the central axis of the support plate to switch different reflectors to reflect the laser beam.

[0008] Optionally, it also includes: a second adjustment member for adjusting the pitch angle of the reflector, wherein the pitch angle is the angle between the reflecting surface of the reflector and the horizontal plane; and a third adjustment member for adjusting the horizontal angle of the reflector, wherein the horizontal angle is the angle between the reflector and a reference vertical plane.

[0009] Optionally, the distance between the center of the first aperture and the center of the second aperture is less than or equal to 0.8 times the Rayleigh distance of the side of the collimating component away from the semiconductor laser.

[0010] Optionally, the aperture of the first aperture is 95% to 105% of the diameter of the laser beam after being collimated by the collimation assembly; the aperture of the second aperture is 95% to 105% of the diameter of the laser beam after being collimated by the collimation assembly.

[0011] The present invention also provides a detection method, comprising: providing the detection system of the present invention, when the semiconductor laser and the reflector do not form external cavity feedback, the semiconductor laser has a first threshold current; closing the baffle switch, the semiconductor laser and the reflector do not form external cavity feedback, and the semiconductor laser has the first threshold current; injecting a first current into the semiconductor laser, the first current is less than the first threshold current; opening the baffle switch, adjusting the angle of the reflector, so that the semiconductor laser and the reflector form external cavity feedback, the semiconductor laser has a second threshold current, the second threshold current is less than the first current; in the process of adjusting the angle of the reflector, obtaining the functional relationship between the signal value output by the beam analyzer and the angle; determining the test angle of the reflector according to the maximum value of the signal value in the functional relationship; setting the reflector at the test angle, injecting a second current into the semiconductor laser to perform aging treatment on the semiconductor laser, the second current is greater than the first threshold current, and in the process of the aging treatment, judging the stability of the semiconductor laser according to the signal value output by the beam analyzer.

[0012] Optionally, adjusting the angle of the reflector includes: adjusting the pitch angle and the horizontal angle of the reflector, the pitch angle being the angle between the reflecting surface of the reflector and the horizontal plane, and the horizontal angle being the angle between the reflector and a reference vertical plane; in the process of adjusting the angle of the reflector, obtaining a functional relationship between a signal value output by the beam analyzer and changes in the angle, including: in the process of adjusting the angle of the reflector, obtaining a functional relationship between a signal value output by the beam analyzer and changes in the pitch angle and the horizontal angle.

[0013] Optionally, adjusting the angle of the reflector includes: coarsely adjusting the angle of the reflector within a first angle range; after coarsely adjusting the angle of the reflector, finely adjusting the angle of the reflector within a second angle range; wherein, in the process of adjusting the angle of the reflector, obtaining a functional relationship between a signal value output by the beam analyzer and a change in the angle, including: in the process of coarsely adjusting the angle of the reflector, obtaining a first functional relationship between a signal value output by the beam analyzer and a change in the angle; using the angle of the reflector corresponding to a maximum value of the signal value in the first functional relationship and a threshold multiple of the maximum value of the signal value in the first functional relationship as the second angle range; in the process of finely adjusting the angle of the reflector, obtaining a second functional relationship between a signal value output by the beam analyzer and a change in the angle; wherein, determining the test angle of the reflector according to the maximum value of the signal value in the functional relationship includes: determining the test angle of the reflector according to the maximum value of the signal value in the second functional relationship.

[0014] Optionally, the reflector group includes a support plate and a plurality of the reflectors fixed to the support plate, and the plurality of the reflectors are arranged circumferentially around the central axis of the support plate; at least a part of the reflectors have different reflectivities; the detection method also includes: using a first adjustment member to drive the support plate to rotate around the central axis of the support plate to switch different reflectors to reflect the laser beam.

[0015] The technical solution of the present invention has the following beneficial effects:

[0016] The detection method provided by the technical solution of the present invention is as follows: when the semiconductor laser and the reflector do not form external cavity feedback, the semiconductor laser has a first threshold current; when the baffle switch is closed, the semiconductor laser and the reflector do not form external cavity feedback, and the semiconductor laser has a first threshold current; a first current is injected into the semiconductor laser, and the first current is less than the first threshold current; the baffle switch is opened, and the angle of the reflector is adjusted so that the semiconductor laser and the reflector form external cavity feedback, and the semiconductor laser has a second threshold current, and the second threshold current is less than the first current; since the first aperture and the second aperture are set, the overlap of the paths of the outgoing light and the feedback light from the semiconductor laser to the reflector can be improved, thereby reducing the probability of catastrophic optical damage to the cavity surface of the semiconductor laser. Then, the functional relationship between the signal value output by the beam analyzer and the angle is obtained by adjusting the angle of the reflector; the test angle of the reflector is determined according to the maximum value of the signal value in the functional relationship. When the reflector is at the test angle, the overlap of the paths of the output light and the feedback light from the semiconductor laser to the reflector is further improved, further reducing the probability of catastrophic optical damage to the cavity surface of the semiconductor laser. Since the first current is less than the first threshold current and greater than the second threshold current, the signal output by the beam analyzer is not too high, so the change of the signal output by the beam analyzer can be more obviously obtained, the maximum value of the signal value in the functional relationship is accurately obtained, and the test angle of the reflector is accurately obtained. The reflector is set at the test angle to inject a second current into the semiconductor laser to perform an aging treatment on the semiconductor laser. The second current is greater than the first threshold current. During the aging process, the stability of the semiconductor laser is judged according to the signal value output by the beam analyzer, so that the reliability of the semiconductor laser is accurately detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A top view of the structure of the detection system in this application;

[0019] Figure 2 is a structural diagram of the reflector assembly in this application;

[0020] Figure 3A diagram showing the relative positions of the laser beam and the first aperture after being collimated by the collimation assembly in the present application;

[0021] Figure 4 A diagram showing the relative positions of the laser beam and the second aperture after being collimated by the collimation assembly in the present application;

[0022] Figure 5 The light spot diagrams obtained by the beam analyzer for coarse adjustment and fine adjustment of the angle of the reflector respectively;

[0023] Figure 6 Flow chart of the test method in this application. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0026] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] An embodiment of the present application provides a detection system, referring to Figure 1 ,include:

[0028] Beam splitter 140;

[0029] A semiconductor laser 100 located at a first side of the beam splitter 140, the semiconductor laser 100 being suitable for outputting a laser beam;

[0030] A collimating assembly 110, a first aperture 120 and a second aperture 130 are sequentially arranged in the optical path from the semiconductor laser 100 to the beam splitter 140;

[0031] A reflector assembly 150 is located on the second side of the beam splitter 140, and the reflector assembly 150 includes a reflector 151 (refer to Figure 2);

[0032] a beam profiler 180 located on a third side of the beam splitter 140;

[0033] A focusing lens 170 , located between the beam profiler 180 and the beam splitter 140 ;

[0034] A baffle switch 160, used to be located between the reflector assembly 150 and the beam splitter 140;

[0035] The beam splitter 140 is used to transmit part of the laser beam to the beam analyzer 180 and reflect part of the laser beam to the reflector 151 when the baffle switch 160 is turned on; the reflector 151 is used to reflect the laser beam along the original optical path back to the semiconductor laser 100 when the baffle switch 160 is turned on.

[0036] In one embodiment, the focusing lens 170 is placed within the Rayleigh interval of the collimating assembly 110 on the side away from the semiconductor laser 100. In this way, the intensity uniformity of the laser beam spot received by the beam profiler 180 is improved.

[0037] In one embodiment, beam profiler 180 is a charge coupled device image sensor.

[0038] In one embodiment, reference Figure 2 The reflector group 150 includes a support plate 152 and a plurality of reflectors 151 fixed to the support plate 152 , and the plurality of reflectors 151 are arranged circumferentially around the central axis of the support plate 152 ; at least a portion of the reflectors 151 have different reflectivities.

[0039] In one embodiment, the detection system further includes a first adjusting member, which is used to drive the support plate 152 to rotate around the central axis of the support plate 152 to switch different reflectors 151 to reflect the laser beam. The first adjusting member is, for example, an electric adjusting member.

[0040] In one embodiment, the detection system further includes a second adjusting member and a third adjusting member, wherein the second adjusting member is used to adjust the pitch angle of the reflector 151, and the pitch angle of the reflector 151 is the angle between the reflective surface of the reflector 151 and the horizontal plane; and the third adjusting member is used to adjust the horizontal angle of the reflector 151. The horizontal angle of the reflector 151 is the angle between the reflector 151 and the reference vertical plane. The reference vertical plane is perpendicular to the horizontal plane. The pitch angle and the horizontal angle of the reflector 151 are adjusted by the second adjusting member and the third adjusting member, so that the reflector 151 is set in an optimized position, thereby increasing the degree of overlap between the feedback light and the output light. The second adjusting member is, for example, an electric adjusting member. The third adjusting member is, for example, an electric adjusting member.

[0041] In one embodiment, the second adjusting member has an adjustment accuracy of the pitch angle of the reflector 151 that is greater than or equal to (5.7*10-5 )Spend.

[0042] Exemplarily, the second adjusting member adjusts the pitch angle of the reflector 151 with an adjustment accuracy of (5.7*10 -5 ) Degree~(12*10 -5 )Spend.

[0043] The adjustment accuracy of the third adjustment member on the horizontal angle of the reflector 151 is greater than or equal to (5.7*10 -5 )Spend.

[0044] Exemplarily, the third adjusting member adjusts the horizontal angle of the reflector 151 with an accuracy of (5.7*10 -5 ) Degree~(12*10 -5 )Spend.

[0045] The reflector 151 has a reflecting surface and a first surface opposite to each other. The first surface and the reflecting surface are arranged opposite to each other, and the arrangement direction of the first surface and the reflecting surface is parallel to a horizontal plane.

[0046] In one embodiment, the distance between the center of the first aperture 120 and the center of the second aperture 130 is less than or equal to 0.8 times, for example, 0.6 times, 0.4 times, 0.2 times or 0.1 times, of the Rayleigh distance of the collimating component away from the semiconductor laser, thereby improving the ability to constrain the overlap of the paths of the outgoing light and the feedback light from the semiconductor laser to the reflector.

[0047] In one embodiment, the aperture of the first aperture 120 is 95% to 105%, such as 95%, 97%, 99%, 100%, 101%, 103% or 105%, of the diameter of the laser beam after collimation by the collimation assembly 110; the aperture of the second aperture 130 is 95% to 105%, such as 95%, 97%, 99%, 100%, 101%, 103% or 105%, of the diameter of the laser beam after collimation by the collimation assembly 110. This improves the ability to constrain the overlap of the paths of the outgoing light and the feedback light from the semiconductor laser to the reflector.

[0048] Figure 3 FIG. 1 is a diagram showing the relative positions of the laser beam A and the first aperture 120 after being collimated by the collimation assembly in the present application. Figure 4 FIG. 1 is a diagram showing the relative positions of the laser beam A and the second aperture 130 after being collimated by the collimation assembly in the present application. The laser beam A is limited by the first aperture 120 and the second aperture 130 .

[0049] The first aperture 120 and the second aperture 130 jointly constrain the path of the laser beam, thereby increasing the degree of overlap between the paths of the outgoing light and the feedback light of the semiconductor laser.

[0050] Another embodiment of the present invention further provides a detection method, referring to Figure 6 ,include:

[0051] Step S1: providing the above detection system, when the semiconductor laser and the reflector do not form external cavity feedback, the semiconductor laser has a first threshold current;

[0052] Step S2: closing the baffle switch, the semiconductor laser and the reflector do not form external cavity feedback, and the semiconductor laser has a first threshold current;

[0053] Step S3: injecting a first current into the semiconductor laser, where the first current is less than the first threshold current;

[0054] Step S4: turning on the baffle switch and adjusting the angle of the reflector so that the semiconductor laser and the reflector form external cavity feedback, and the semiconductor laser has a second threshold current, which is smaller than the first current;

[0055] Step S5: in the process of adjusting the angle of the reflector, obtaining a functional relationship between the signal value output by the beam profiler and the change of the angle;

[0056] Step S6: determining the test angle of the reflector according to the maximum value of the signal value in the functional relationship;

[0057] Step S7: Setting the reflector at the test angle to inject a second current into the semiconductor laser to perform aging treatment on the semiconductor laser, wherein the second current is greater than the first threshold current, and during the aging treatment, determining the stability of the semiconductor laser based on the signal value output by the beam analyzer.

[0058] In this embodiment, since the first aperture and the second aperture are provided, the overlap of the paths of the outgoing light and the feedback light from the semiconductor laser to the reflector can be improved, and the probability of catastrophic optical damage to the cavity surface of the semiconductor laser can be reduced. Then, the functional relationship between the signal value output by the beam analyzer and the change of the angle is obtained by adjusting the angle of the reflector; the test angle of the reflector is determined according to the maximum value of the signal value in the functional relationship. When the reflector is at the test angle, the overlap of the paths of the outgoing light and the feedback light from the semiconductor laser to the reflector is further improved, and the probability of catastrophic optical damage to the cavity surface of the semiconductor laser is further reduced. Since the first current is less than the first threshold current and greater than the second threshold current, the signal output by the beam analyzer is not too high, so the change of the signal output by the beam analyzer can be more obviously obtained, the maximum value of the signal value in the functional relationship is accurately obtained, and the test angle of the reflector is accurately obtained. The reflector is set at the test angle to inject a second current into the semiconductor laser to perform aging treatment on the semiconductor laser, and the second current is greater than the first threshold current. During the aging treatment, the stability of the semiconductor laser is judged according to the signal value output by the beam analyzer, so that the reliability of the semiconductor laser is accurately detected.

[0059] In one embodiment, adjusting the angle of the reflector includes: adjusting the pitch angle and the horizontal angle of the reflector, the pitch angle being the angle between the reflecting surface of the reflector and the horizontal plane, and the horizontal angle being the angle between the reflector and a reference vertical plane.

[0060] In one embodiment, in the process of adjusting the angle of the reflector, the functional relationship between the signal value output by the beam analyzer and the change of the angle is obtained, including: in the process of adjusting the angle of the reflector, the functional relationship between the signal value output by the beam analyzer and the change of the pitch angle and the horizontal angle is obtained.

[0061] In one embodiment, adjusting the angle of the reflector includes: coarsely adjusting the angle of the reflector within a first angle range; after coarsely adjusting the angle of the reflector, finely adjusting the angle of the reflector within a second angle range; wherein, in the process of adjusting the angle of the reflector, obtaining a functional relationship between the signal value output by the beam analyzer and the angle, including: in the process of coarsely adjusting the angle of the reflector, obtaining a first functional relationship between the signal value output by the beam analyzer and the angle; using the angle of the reflector corresponding to the maximum value of the signal value in the first functional relationship and a threshold multiple of the maximum value of the signal value in the first functional relationship as the second angle range; in the process of finely adjusting the angle of the reflector, obtaining a second functional relationship between the signal value output by the beam analyzer and the angle.

[0062] Figure 5 The light spot diagrams obtained by the beam analyzer for coarse adjustment and fine adjustment of the angle of the reflector, respectively, Figure 5 The left diagram in the figure is a spot diagram obtained by coarsely adjusting the angle of the reflector by the beam profiler. Figure 5 The diagram on the right is for Figure 5 The spot patterns in the dashed box on the left of the figure are obtained by coarsely adjusting the beam profiler in the corresponding angle range. Figure 5 In the left diagram, the range of the coarse adjustment of the horizontal angle of the reflector is θ1 to θ2, and the range of the coarse adjustment of the pitch angle of the reflector is φ1 to φ2. Figure 5 In the diagram on the right, the range for fine adjustment of the horizontal angle of the reflector is θ3 to θ4, and the range for coarse adjustment of the pitch angle of the reflector is φ3 to φ4.

[0063] In one embodiment, determining the test angle of the reflector according to the maximum value of the signal value in the functional relationship includes: determining the test angle of the reflector according to the maximum value of the signal value in the second functional relationship.

[0064] In one embodiment, the reflector group includes a support plate and a plurality of the reflectors fixed to the support plate, and the plurality of the reflectors are arranged circumferentially around the central axis of the support plate; at least a part of the reflectors have different reflectivities; the detection method further includes: using a first adjustment member to drive the support plate to rotate around the central axis of the support plate to switch different reflectors to reflect the laser beam.

[0065] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A detection method of a detection system, characterized in that: The detection system comprises: A beam splitter; a semiconductor laser located on a first side of the beam splitter, the semiconductor laser being suitable for outputting a laser beam; a collimating assembly, a first aperture and a second aperture arranged in sequence in the optical path from the semiconductor laser to the beam splitter; a reflector group located on a second side of the beam splitter, the reflector group comprising a reflector, and when the semiconductor laser and the reflector do not form an external cavity feedback, the semiconductor laser has a first threshold current; a beam analyzer located on a third side of the beam splitter; a focusing mirror located between the beam analyzer and the beam splitter; a baffle switch used to be located between the reflector group and the beam splitter; wherein the beam splitter is used to transmit part of the laser beam to the beam analyzer and reflect part of the laser beam to the reflector when the baffle switch is turned on; and the reflector is used to reflect the laser beam back to the semiconductor laser along the original optical path when the baffle switch is turned on; The detection method comprises: The baffle switch is closed, the semiconductor laser and the reflector do not form external cavity feedback, and the semiconductor laser has a first threshold current; a first current is injected into the semiconductor laser, and the first current is less than the first threshold current; Turning on the baffle switch and adjusting the angle of the reflector so that the semiconductor laser and the reflector form external cavity feedback, the semiconductor laser has a second threshold current, and the second threshold current is smaller than the first current; In the process of adjusting the angle of the reflector, obtaining a functional relationship between the signal value output by the beam profiler and the change of the angle; Determining a test angle of the reflector according to a maximum value of a signal value in the functional relationship; The reflector is set at the test angle to inject a second current into the semiconductor laser to perform aging treatment on the semiconductor laser, wherein the second current is greater than the first threshold current. During the aging treatment, the stability of the semiconductor laser is judged according to the signal value output by the beam analyzer.

2. The detection method according to claim 1, characterized in that: Adjusting the angle of the reflector includes: adjusting the pitch angle and the horizontal angle of the reflector, wherein the pitch angle is the angle between the reflecting surface of the reflector and the horizontal plane, and the horizontal angle is the angle between the reflector and the reference vertical plane; In the process of adjusting the angle of the reflector, the functional relationship between the signal value output by the beam analyzer and the change of the angle is obtained, including: in the process of adjusting the angle of the reflector, the functional relationship between the signal value output by the beam analyzer and the change of the pitch angle and the horizontal angle is obtained.

3. The detection method according to claim 1, characterized in that: Adjusting the angle of the reflector includes: roughly adjusting the angle of the reflector within a first angle range; and after roughly adjusting the angle of the reflector, finely adjusting the angle of the reflector within a second angle range; Wherein, in the process of adjusting the angle of the reflector, obtaining the functional relationship between the signal value output by the beam analyzer and the change of the angle includes: In the process of roughly adjusting the angle of the reflector, a first functional relationship between the signal value output by the beam analyzer and the change of the angle is obtained; The angle of the reflector corresponding to the maximum value of the signal value in the first functional relationship and the threshold multiple of the maximum value of the signal value in the first functional relationship is used as the second angle range; In the process of finely adjusting the angle of the reflector, a second functional relationship between the signal value output by the beam analyzer and the angle is obtained; Wherein, determining the test angle of the reflector according to the maximum value of the signal value in the functional relationship includes: determining the test angle of the reflector according to the maximum value of the signal value in the second functional relationship.

4. The detection method according to claim 1, characterized in that: The reflector group includes a support plate and a plurality of reflectors fixed to the support plate, wherein the plurality of reflectors are circumferentially arranged around a central axis of the support plate; At least some number of said reflectors have different reflectivities; The detection method further includes: using a first adjustment member to drive the support plate to rotate around the central axis of the support plate, so as to switch different reflectors to reflect the laser beam.

5. The detection method according to claim 1, characterized in that: The focusing mirror is placed within the Rayleigh interval of the collimating component on a side away from the semiconductor laser.

6. The detection method according to claim 1 or 4, characterized in that: The detection system also includes: a second adjustment member for adjusting the pitch angle of the reflector, wherein the pitch angle is the angle between the reflecting surface of the reflector and the horizontal plane; and a third adjustment member for adjusting the horizontal angle of the reflector, wherein the horizontal angle is the angle between the reflector and a reference vertical plane.

7. The detection method according to claim 1, characterized in that: The distance between the center of the first aperture and the center of the second aperture is less than or equal to 0.8 times the Rayleigh distance of the collimating assembly facing away from the semiconductor laser.

8. The detection method according to claim 1, characterized in that: The aperture of the first aperture is 95% to 105% of the diameter of the laser beam after being collimated by the collimation assembly; the aperture of the second aperture is 95% to 105% of the diameter of the laser beam after being collimated by the collimation assembly.

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