Device for detecting far-field divergence angle of semiconductor laser chip

Abstract

The utility model provides a detection device for a far-field divergence angle of a semiconductor laser chip. The detection device comprises an objective table, a steering engine, a photoelectric detector and a photoelectric detector support. The objective table is used for bearing and fixing a tested semiconductor laser chip and a PCB (Printed Circuit Board) for realizing power supply and heat dissipation functions for the semiconductor laser chip; a rotating shaft of the steering engine is connected with the objective table to drive the objective table to realize rotary scanning of the semiconductor laser chip; the photoelectric detector reads the light emitting intensity of the laser chip. During measurement, a screw hole in the horizontal direction of an objective table is connected with a rotating shaft of a steering engine, the steering engine rotates step by step, and the far-field divergence angle of a semiconductor laser chip in the horizontal direction is tested; then connecting a screw hole in the vertical direction of the objective table with a rotating shaft of a steering engine, rotating the steering engine in a stepping manner, and testing the far-field divergence angle of the semiconductor laser chip in the vertical direction. The testing device is simple and low in cost, and a testing method based on the testing device is simple, easy to implement, high in accuracy and wide in application range.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor lasers, in particular to a detection device for the far-field divergence angle of a semiconductor laser chip. Background Art

[0002] Semiconductor lasers are widely used in optical communication, optical interconnection, optical measurement, optical sensing and other fields. Due to the waveguide structure of the semiconductor laser, the output beam of the semiconductor laser usually has a large far-field divergence angle and an asymmetric distribution. The divergence angle in the horizontal direction of the light-emitting end face, i.e., the slow axis direction, is about 10 to 20°, and the divergence angle in the vertical direction of the light-emitting end face, i.e., the fast axis direction, is about 30 to 50°. Therefore, it is of great significance to test and characterize the far-field divergence angle of semiconductor lasers.

[0003] A common method for measuring the far-field divergence angle of a semiconductor laser is to use an array CCD to image the far-field beam to obtain the light intensity distribution, and then calculate the far-field divergence angle. However, this method is limited by the size of the array CCD and is difficult to measure lasers with large divergence angles. If a larger CCD is used, the cost of the device will inevitably increase significantly; if a lens is used to focus the Gaussian beam, the alignment of the device will be more demanding.

[0004] Document CN111351641A discloses a method and device for measuring the far-field divergence angle of a laser: this method establishes an X, Y, and Z three-dimensional coordinate system, with the Y axis as the rotation axis and the XZ measurement plane. The laser to be measured is placed at the origin of the coordinate system, and the detector is located on the measurement plane with the luminous surface facing the laser; the detector rotates along the rotation axis on the detection surface to obtain the diameter of the far-field light spot, and then calculates the far-field divergence angle in the horizontal direction; the laser is rotated 90° around the Z axis, and the second step is repeated to obtain the far-field divergence angle in the vertical direction. However, this method rotates the detector along an arc, which requires a large space and requires a matching arc-shaped slide rail to achieve precise control of the detector position. At the same time, the movement of the detector may be difficult to coincide with the long and short axes of the far-field elliptical light spot.

[0005] Document CN117249976 discloses a device for detecting the divergence angle of a semiconductor laser: the device mainly consists of a detector 1 fixed on a detector mounting frame, a detector 2 fixed on an arc-shaped arm, a rotating mechanism for mounting the laser, and a servo motor for controlling the rotation of the arc-shaped arm. During measurement, in the first step, the rotating mechanism drives the laser to rotate, and the fixed detector 1 measures the divergence angle of the laser in the horizontal direction; in the second step, the laser is reset and fixed, and the arc-shaped arm is driven by the servo motor to rotate the detector 2, and the detector 2 is rotated and scanned in the vertical direction to measure the divergence angle of the laser in the vertical direction. However, this device requires two detectors, two rotating devices, an arc-shaped arm, and a limit block and a conical top rod required to adjust the position of the detector 2, and the overall structure of the device is complex. At the same time, the device requires that the intersection of the arc-shaped arm rotation center line and the horizontal line coincide with the center of the laser light source, which makes the distance between the detector 2 and the light source determined solely by the radius of the arc-shaped arm and cannot be flexibly adjusted. Utility Model Content

[0006] In order to solve the above problems, the utility model provides a detection device for the far-field divergence angle of a semiconductor laser chip. The utility model aims to provide a low-cost and easy-to-build semiconductor laser chip far-field divergence angle testing device. The testing method is simple, suitable for ordinary technicians to operate, and can ensure a certain measurement accuracy.

[0007] In order to achieve the above object, the utility model provides a detection device for the far-field divergence angle of a semiconductor laser chip, and the technical solution adopted is as follows:

[0008] A device for detecting the far-field divergence angle of a semiconductor laser chip, comprising:

[0009] A stage, the stage is used to fix a PCB board, and the semiconductor laser chip to be tested is mounted on the PCB board;

[0010] A steering gear, the steering gear is connected to the stage through a rotating shaft, and the steering gear is connected to a computer signal, so as to step by step with a set angle as a step length according to a control signal fed by the computer, drive the stage to realize the rotation scanning of the semiconductor laser chip, and feed the angle position information to the computer in real time;

[0011] A photoelectric detector is connected to the computer signal to detect the light intensity emitted from the end face of the semiconductor laser chip, and converts the light intensity signal into an electrical signal to feed the computer.

[0012] Furthermore, the stage is used to ensure that the position of the light emitting end face does not change after the semiconductor laser chip is rotated 90°.

[0013] Furthermore, a photodetector bracket is provided on which the photodetector is fixed, and is used to adjust the height and position of the photodetector so that the photosensitive surface of the photodetector faces the light emitting end face of the semiconductor laser chip at the center position of the steering gear.

[0014] Furthermore, a calibration point is provided on the edge of the stage for indicating the position where the light emitting end face of the semiconductor laser chip is required to be located after installation.

[0015] Furthermore, the loading platform has two surfaces perpendicular to each other, and a first screw hole and a second screw hole are respectively provided on the two surfaces, the first screw hole and the second screw hole are both adapted to the rotating shaft of the servo, the central axes of the first screw hole and the second screw hole intersect perpendicularly at the calibration point, and the distances between the center of the surface and the calibration point of the first screw hole and the second screw hole are equal.

[0016] Furthermore, in the test, the rotating shaft of the servo is connected to the first screw hole and the second screw hole in sequence, so that the stage is rotated 90°, so as to ensure that the position of the light emitting end face does not change after the semiconductor laser chip is rotated 90°.

[0017] Furthermore, screw holes are reserved on the stage to fix a PCB board used for power supply and heat dissipation of the semiconductor laser chip.

[0018] The utility model has at least the following beneficial effects:

[0019] (1) The utility model adopts a measuring device that fixes the photoelectric detector and rotates the semiconductor laser chip to be measured, avoiding the disadvantages of rotating the detector on an arc track, which requires a large measurement space, has a complex slide rail structure, and is difficult to accurately control. At the same time, the distance between the semiconductor laser chip to be measured and the photoelectric detector is flexibly adjustable, and the divergence angle of semiconductor lasers with a larger power range can be measured;

[0020] (2) The device described in the utility model does not have expensive components such as attenuation plates, CCDs, lenses, etc., thus avoiding the limitation of the divergence angle measurement range caused by the size limitation of the CCD, and can measure the divergence angle of semiconductor laser chips with larger divergence angles. At the same time, the control program can be implemented by a general computer, the test device has a simple architecture, low cost, and is easy to build, which is conducive to promotion;

[0021] (3) The utility model achieves the goal of "ensuring that the position of the light-emitting end face does not change after the semiconductor laser chip is rotated 90°" through the design of the stage, so that the measurement of the far-field divergence angle in the horizontal and vertical directions of the semiconductor laser chip can be achieved by simply changing the connecting screw holes of the stage and the steering gear shaft. The test method is simple and easy to use, and is suitable for ordinary technicians;

[0022] (4) The far-field divergence angle test method of a semiconductor laser chip proposed in the utility model has high accuracy. In order to verify the accuracy of the test method, the test device is used to test the far-field divergence angle of a standard single-mode optical fiber. The selected standard single-mode optical fiber 1550nm optical mode field diameter is 9.8~10.8um, and the calculated theoretical far-field divergence angle is 6.2~6.8°. Using a 1550nm light source and testing according to the test method, the test results show that the far-field divergence angle in the horizontal direction is 6.5°, and the far-field divergence angle in the vertical direction is 6.5°. It is proved that the test method has high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0024] Figure 1 A schematic structural diagram of a device for detecting the far-field divergence angle of a semiconductor laser chip according to an embodiment of the utility model is shown.

[0025] Figure 2 A three-dimensional schematic diagram of a stage in a device for detecting the far-field divergence angle of a semiconductor laser chip according to an embodiment of the utility model is shown.

[0026] Figure 3 The far-field divergence angle test results of the semiconductor laser chip in the horizontal direction, that is, the slow axis direction, which are actually tested according to the embodiment of the utility model are shown.

[0027] Figure 4 The test results of the far-field divergence angle of the semiconductor laser chip in the vertical direction, that is, the fast axis direction, which are actually tested according to the embodiment of the utility model are shown.

[0028] In the figure, 1 is a calibration point, 2 is a first screw hole, 3 is a second screw hole, and 4 is a screw hole. DETAILED DESCRIPTION

[0029] The following describes the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0030] In the description of the present invention, unless otherwise specified, "multiple" means two or more; the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third" and the like are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] The specific implementation of the utility model is further described in detail below in conjunction with the drawings and embodiments.

[0033] The present utility model provides a device for detecting the far-field divergence angle of a semiconductor laser chip. Figure 1 As shown, the detection device for the far-field divergence angle of the semiconductor laser chip includes a stage, a steering gear, a photoelectric detector, a photoelectric detector bracket and a computer.

[0034] The computer described in this article can be understood as a signal processing device, which is connected to the steering gear and the photoelectric detector by signals. The signal connection methods include but are not limited to wired connection, wireless connection, etc. On the one hand, it controls the operation of the steering gear to achieve the purpose of automatic detection (the specific control method will be described in detail later). On the other hand, it receives the electrical signal fed by the photoelectric detector to obtain the light intensity signal, and realizes the detection of the far-field divergence angle of the semiconductor laser chip according to the light intensity signal.

[0035] like Figure 2 As shown, it is a schematic diagram of the three-dimensional structure of the stage. The stage is used to carry and fix the semiconductor laser chip under test and the PCB board that realizes the power supply and heat dissipation functions for the semiconductor laser chip. It can ensure that the position of the light-emitting end face does not change after the semiconductor laser chip is rotated 90°.

[0036] The semiconductor laser chip under test is injected with a certain current and can output a laser beam of a certain wavelength.

[0037] The rotating shaft of the servo is successively connected to the first screw hole 2 and the second screw hole 3 set on the stage. It can be controlled by a computer to rotate in a certain angle range with a certain angle as the step length, driving the stage to realize the rotation scanning of the semiconductor laser, and feed back the angle position information after each rotation step to the computer.

[0038] Photoelectric detectors are used to convert the light intensity signal at a certain point into an electrical signal and feed it back to the computer;

[0039] The photodetector bracket is used to fix the photodetector, and can adjust the height and position of the photodetector so that the photosensitive surface of the photodetector faces the light emitting end face of the semiconductor laser chip at the center position of the steering gear.

[0040] In some embodiments, the semiconductor laser chip under test is a distributed feedback laser with a spot converter, the wavelength of the output laser beam is 1358 nm, and the injection current of the semiconductor laser chip under test is 100 mA during the test.

[0041] In some embodiments, Figure 2 As shown, a marking point 1 is engraved on the edge of the stage to indicate the position where the light-emitting end face of the semiconductor laser chip is required to be after installation.

[0042] In some embodiments, Figure 2 As shown, the two perpendicular surfaces of the stage have identical first screw holes 2 and second screw holes 3 for connecting with the shaft of the servo, the central axes of the first screw holes 2 and the second screw holes 3 intersect perpendicularly at the calibration point 1, and the distances between the center of the surface of the first screw hole 2 and the second screw hole 3 and the calibration point 1 are equal. In the test, the servo shaft is connected to the two screw holes, namely the first screw hole 2 and the second screw hole 3, successively, which can rotate the stage 90°, achieving the goal of "ensuring that the position of the light-emitting end face does not change after the semiconductor laser chip is rotated 90°".

[0043] In some embodiments, a screw hole 4 is reserved on the stage for fixing a PCB board that realizes the power supply and heat dissipation functions of the semiconductor laser chip, and for ensuring that the PCB board is fixed and does not fall after the stage is rotated 90°. It is also used to ensure that the light-emitting end face of the semiconductor laser chip is located at the calibration point 1 at the edge of the stage, to prevent the light-emitting end face of the semiconductor laser chip from being reflected by the stage surface when the light-emitting end face is not at the edge of the stage and affecting the measurement results, and to prevent the light-emitting end face of the semiconductor laser chip from deviating from the calibration point and causing measurement errors.

[0044] A method for detecting the far-field divergence angle of a semiconductor laser chip is provided. The method is an example of a method for using the detection device described above. The method steps are as follows:

[0045] S1. Fix the PCB board with the semiconductor laser chip to be tested, which is used for power supply and heat dissipation, through the stage screw hole 4, so that the light-emitting end face of the semiconductor laser chip to be tested coincides with the calibration point 1 on the stage. The computer controls the steering gear shaft to return to the center, and connects the steering gear shaft to the first screw hole 2 in the horizontal direction of the stage for connecting the steering gear shaft, so that the light-emitting end face of the semiconductor laser chip to be tested faces the center line of the steering gear. The photodetector is fixed by the photodetector bracket, so that the photosensitive surface of the photodetector is facing the light-emitting end face of the semiconductor laser chip to be tested, and the distance between the two is appropriate for easy testing;

[0046] S2. The computer runs the control program to make the servo drive the stage to rotate forward through half of the set scanning range angle value to the starting point of the scan, and start step scanning with a certain angle as the step length. With each step of the scan, the computer records the detector reading and rotates the entire set scanning range angle value in the reverse direction to complete the measurement of the divergence angle in the horizontal direction, i.e., the slow axis direction. At this time, the servo is at the end point of the scan;

[0047] S3. Connect the servo shaft to the second screw hole 3 in the vertical direction of the stage for connecting the servo shaft. The computer runs the control program and starts scanning with the same step length as in S2. With each step of scanning, the computer records the detector reading and rotates the entire set scanning range angle value in the positive direction to complete the measurement of the divergence angle in the vertical direction, i.e., the fast axis direction. At this time, the servo returns to the scanning starting point again.

[0048] So far, the far-field divergence angle measurement of the semiconductor laser chip under test in two directions has been completed. The measurement results in the horizontal direction, i.e., the slow axis direction, are as follows: Figure 3 As shown, the far-field divergence angle of the semiconductor laser chip in the horizontal direction, i.e. the slow axis direction, is 20.4°; the measurement results in the vertical direction, i.e. the fast axis direction, are as follows Figure 4 As shown, the far-field divergence angle of the semiconductor laser chip in the vertical direction, i.e., the fast axis direction, is 26.0°.

[0049] In summary, the utility model proposes Figure 1 A semiconductor laser chip far-field divergence angle test device is shown, through Figure 2 The design of the stage shown in the figure makes it possible to achieve the goal of "ensuring that the position of the light-emitting end face does not change after the semiconductor laser chip is rotated 90°" by simply changing the first screw hole 2 and the second screw hole 3 connecting the stage and the steering gear shaft, thereby realizing the measurement of the far-field divergence angle of the semiconductor laser chip in the horizontal and vertical directions. The test device is simple and low-cost; the test method is simple and easy to implement, with high accuracy; there are few restrictions on the semiconductor laser chip being tested, and it has a wide range of applications.

[0050] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The scope of patent protection of the present invention should be limited by the claims.

Claims

1. A detection device for the far-field divergence angle of a semiconductor laser chip, It is characterized in that include: A stage, the stage is used to fix a PCB board, and the semiconductor laser chip to be tested is mounted on the PCB board; A steering gear, the steering gear is connected to the stage through a rotating shaft, and the steering gear is connected to a computer signal, so as to step by step with a set angle as a step length according to a control signal fed by the computer, drive the stage to realize the rotation scanning of the semiconductor laser chip, and feed the angle position information to the computer in real time; A photoelectric detector is connected to the computer signal to detect the light intensity emitted from the end face of the semiconductor laser chip, and converts the light intensity signal into an electrical signal to feed the computer.

2. The device for detecting the far-field divergence angle of a semiconductor laser chip according to claim 1, It is characterized in that The stage is used to ensure that the position of the light emitting end face does not change after the semiconductor laser chip is rotated 90°.

3. The device for detecting the far-field divergence angle of a semiconductor laser chip according to claim 1, It is characterized in that A photoelectric detector bracket is provided on which the photoelectric detector is fixed, and is used to adjust the height and position of the photoelectric detector so that the photosensitive surface of the photoelectric detector faces the light-emitting end surface of the semiconductor laser chip at the center position of the steering gear.

4. The device for detecting the far-field divergence angle of a semiconductor laser chip according to claim 1, It is characterized in that A calibration point is arranged on the edge of the stage to indicate the position where the light emitting end face of the semiconductor laser chip is required to be after installation.

5. The device for detecting the far-field divergence angle of a semiconductor laser chip according to claim 4, It is characterized in that The loading platform has two surfaces perpendicular to each other, and a first screw hole and a second screw hole are respectively arranged on the two surfaces. The first screw hole and the second screw hole are both adapted to the rotating shaft of the servo, and the central axes of the first screw hole and the second screw hole intersect perpendicularly at the calibration point, and the distances between the center of the surface and the calibration point of the first screw hole and the second screw hole are equal.

6. The device for detecting the far-field divergence angle of a semiconductor laser chip according to claim 5, It is characterized in that During the test, the rotating shaft of the servo is connected to the first screw hole and the second screw hole in sequence, so that the stage is rotated 90°, so as to ensure that the position of the light emitting end face does not change after the semiconductor laser chip is rotated 90°.

7. The device for detecting the far-field divergence angle of a semiconductor laser chip according to claim 1, It is characterized in that The stage is provided with screw holes for fixing a PCB board for powering and cooling the semiconductor laser chip.

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