High-precision end face coupling device and coupling method

Abstract

The invention discloses a high-precision end face coupling device and a coupling method, and relates to the technical field of optical chip packaging, the end face coupling device comprises a displacement table, a support, a coupling module, a coupling module and a power supply module, the output end of a semiconductor laser chip extends to the outside of one end of the surface of the displacement table, and the input end of the support extends to the outside of one end of the surface of the support. The output end extends out of the other end of the surface of the bracket; a light source that irradiates a gap between the semiconductor laser chip and the optical chip; the camera is used for receiving an optical gap image formed by the gap and coupling the semiconductor laser chip and the optical chip based on the real-time distance; and the power meter is used for measuring the optical power output by the optical chip in the coupling process and judging whether the coupling efficiency between the semiconductor laser chip and the optical chip reaches the highest or not according to the optical power. Whether the semiconductor laser chip is touched or not in the coupling process can be accurately judged, and the end face of the laser cannot be touched during submicron distance coupling.

Description

Technical Field

[0001] The present invention relates to the technical field of optical chip packaging, and particularly to a high-precision end-face coupling device and a coupling method. Background Art

[0002] Currently, in any optical communication and optical sensing system, a semiconductor laser chip for emitting optical signals is indispensable. The optical signals emitted by the semiconductor laser chip usually need to be coupled into an optical chip first. After processing its power, phase, or polarization, they then enter the optical fiber for long-distance transmission. The semiconductor laser chip and the optical chip usually adopt two coupling methods. The first is lens coupling, where at least one lens is placed between them to converge the light emitted by the laser into the waveguide of the optical chip. The second is end-face coupling, where the distance between them is shortened to the micron or sub-micron range to achieve low-loss transmission of optical signals between the two chips.

[0003] The end face of the laser is very sensitive to external forces and contamination. Therefore, its end face cannot be touched by any object during coupling. In the lens coupling scenario, the distance between the semiconductor laser chip and the lens is relatively far, so the requirement that its end face is not touched during coupling can be met. In the end-face coupling scenario, the distance between the semiconductor laser chip and the optical chip is only on the order of microns or sub-microns. During coupling, the end face of the laser is very easy to be touched and squeezed, resulting in deterioration or even failure of the laser performance. Summary of the Invention

[0004] Based on the defects existing in the above-mentioned prior art, the present invention provides a high-precision end-face coupling device and a coupling method, which solve the problem that the end face of the laser in the existing end-face coupling scenario is very easy to be touched and squeezed, resulting in deterioration or even failure of the laser performance.

[0005] The present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a high-precision end-face coupling device for coupling a semiconductor laser chip and an optical chip, including:

[0007] A displacement stage, the top of which is used to place the semiconductor laser chip, and the output end of the semiconductor laser chip extends to the outside of one end of the surface of the displacement stage for emitting optical signals;

[0008] A bracket, fixedly arranged on one side of the displacement stage, the top of which is used to place the optical chip; the input end of the optical chip extends to the outside of one end of the surface of the bracket, and the output end extends to the outside of the other end of the surface of the bracket; the optical chip is used to receive optical signals;

[0009] A light source, arranged below the semiconductor laser chip and the optical chip, for irradiating the gap between the semiconductor laser chip and the optical chip;

[0010] A camera, disposed above the semiconductor laser chip and the optical chip, is configured to receive the optical gap image formed by the gap. The optical gap image is used to obtain the real-time distance between the semiconductor laser chip and the optical chip, and based on the real-time distance, the coupling between the semiconductor laser chip and the optical chip is performed;

[0011] A power meter, disposed on the side where the output end of the optical chip is located, is configured to measure the optical power of the optical signal received by the optical chip during the coupling process, and determine whether the coupling efficiency between the semiconductor laser chip and the optical chip has reached the highest level or meets the application requirements according to the optical power.

[0012] Preferably, the displacement stage is a six-axis displacement stage.

[0013] Preferably, the camera is a CCD camera.

[0014] In a second aspect, the present invention provides a coupling method for a high-precision end-face coupling device, including:

[0015] Placing the semiconductor laser chip and the optical chip on the displacement stage and the bracket respectively;

[0016] Moving the displacement stage unidirectionally to a set initial position, powering on the light source, and the camera acquires the first image of the laser chip, the second image of the optical chip, and the optical gap image;

[0017] Adjusting the semiconductor laser chip and the optical chip to the same height based on the first image and the second image;

[0018] Adjusting the semiconductor laser chip and the optical chip to be parallel based on the first image and the optical gap image, and collecting the current first optical gap image; obtaining the current distance between the semiconductor laser chip and the optical chip through the current first optical gap image;

[0019] If the current distance is greater than the set value, move the semiconductor laser chip unidirectionally to the pre-coupling position, and collect the current second optical gap image. If there is a gap in the second optical gap image, couple the semiconductor laser chip and the optical chip;

[0020] Receiving the coupled optical power through the power meter. If the optical power reaches the set lower limit, the coupling is completed.

[0021] Preferably, the adjusting the semiconductor laser chip and the optical chip to the same height based on the first image and the second image specifically includes the following steps:

[0022] Adjusting the camera in the height direction, and collecting the corresponding second images at different heights; judging the clarity of multiple second images, and fixing the camera at the height corresponding to the second image with the highest clarity;

[0023] Move the displacement stage in the height direction and collect the corresponding first images at different heights; judge the sharpness of multiple first images, and fix the displacement stage at the height corresponding to the first image with the highest sharpness; at this time, the heights of the semiconductor laser chip and the upper surface of the optical chip are the same.

[0024] Preferably, the judging the sharpness of multiple second images specifically includes the following steps:

[0025] Obtain the gray values of all pixels in multiple second images, and arrange all the gray values in each second image from largest to smallest;

[0026] Subtract the gray values in the latter 50% from the gray values in the former 50% to obtain the sharpness difference of each second image. When the sharpness difference is the largest, the corresponding second image is the clearest;

[0027] The judging the sharpness of multiple first images specifically includes the following steps:

[0028] Obtain the gray values of all pixels in multiple first images, and arrange all the gray values in each first image from largest to smallest;

[0029] Subtract the gray values in the latter 50% from the gray values in the former 50% to obtain the sharpness difference of each first image. When the sharpness difference is the largest, the corresponding first image is the clearest.

[0030] Preferably, the aligning the semiconductor laser chip and the optical chip based on the first image and the optical gap image includes the following steps:

[0031] Change the values of the θX and θZ axes of the displacement stage, and collect multiple first images corresponding to different positions; judge the sharpness of multiple first images, and fix the displacement stage at the position corresponding to the first image with the highest sharpness;

[0032] Change the value of the θY of the displacement stage, collect the corresponding multiple optical gap images. If the current optical gap image is a rectangle, the semiconductor laser chip and the optical chip are in a parallel state.

[0033] Preferably, the coupling the semiconductor laser chip and the optical chip includes the following steps:

[0034] Keep the optical chip stationary, and move the displacement stage in the X, Y, and Z axis directions until the power meter collects the maximum optical power value.

[0035] Preferably, it further includes:

[0036] If the current distance is less than the set value, terminate the coupling;

[0037] If there is no gap in the second optical gap image, the coupling is terminated.

[0038] Compared with the prior art, the above at least one technical solution adopted by the present invention can achieve the following beneficial effects:

[0039] The present invention first provides a high-precision end-face coupling device for a semiconductor laser chip and an optical chip. An illumination light source is added at the bottom of the chip, and the width of the illuminated gap is measured above the chip. The real-time distance between the two chips can be accurately obtained, and the semiconductor laser chip and the optical chip are coupled based on the real-time distance. Finally, during the coupling process, the optical power output by the optical chip is measured by a power meter, and it is judged whether the coupling efficiency between the semiconductor laser chip and the optical chip has reached the highest or meets the application requirements according to the optical power.

[0040] At the same time, the present invention also provides a coupling method for a high-precision end-face coupling device. After the semiconductor laser chip and the optical chip are adjusted to the same height and parallel, by monitoring in real time whether the illuminated gap exists, it can be accurately judged whether the semiconductor laser chip is touched during the coupling process, so that when coupling at a sub-micron distance, the end face of the laser will not be touched, improving the reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a side view of a high-precision end-face coupling device of the present invention;

[0043] Figure 2 It is a top view of a high-precision end-face coupling device of the present invention;

[0044] Figure 3 It is a flowchart of a coupling method of a high-precision end-face coupling device of the present invention.

[0045] In the figure: 1 - semiconductor laser chip, 2 - optical chip, 3 - displacement stage, 4 - bracket, 5 - camera, 6 - light source, 7 - power meter. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0047] The present invention provides a high-precision coupling method and device, which can achieve distance control with sub-micron precision and ensure that the end face of the laser is not touched during the coupling process.

[0048] Referring to Figure 1 and Figure 2 , in the two figures, the semiconductor laser chip 1 is placed on a six-axis displacement stage 3 that can move in three directions of X, Y, and Z, and rotate about three axes of θX, θY, and θZ. The output end of the semiconductor laser chip 1 protrudes from the displacement stage 3 by a certain length to prevent the displacement stage 3 from coming into contact with other objects first during the coupling process, which may cause the laser chip to be unable to approach the optical chip 2 with any function. The optical chip 2 is placed on a fixed-position bracket 4, and both its input end (the end close to the semiconductor laser chip 1) and output end (the end close to the power meter 7) protrude from the bracket 4 by a certain length to prevent the bracket 4 from coming into contact with other objects first during the coupling process, which may cause the laser chip to be unable to approach the optical chip 2. An illumination source 6 is placed below the semiconductor laser chip 1 and the optical chip 2. The source 6 is a point source or a line source, and the light emitted by it is transmitted from the gap between the two chips to the upper part of the chips and enters the CCD camera 5. The power meter 7 measures the optical power output by the optical chip 2 to determine whether the coupling efficiency between the two chips has reached the maximum or meets the application requirements. The power meter 7 has a photosensitive surface that can receive light. When the light output from the optical chip 2 enters the photosensitive surface, the power meter 7 can measure the power value of the input light.

[0049] Referring to Figure 3 , the present invention proposes a coupling method for a high-precision end-face coupling device, which specifically includes the following steps:

[0050] S1: Loading: Place the laser chip and the optical chip 2 on the six-axis displacement stage 3 and the bracket 4 respectively.

[0051] S2: The six-axis displacement stage 3 moves unidirectionally (referring to the laser chip always moving towards the optical chip 2) to the initial position (set by software): The six-axis displacement stage 3 carries the laser chip and moves unidirectionally towards the optical chip 2, and stops moving after reaching the set initial position.

[0052] S3: Turn on the illumination source 6: Power on the illumination source 6 placed below the laser chip and the optical chip 2. There are obvious boundary lines of the two chips in the image of the CCD camera 5, andFigure 2 The illuminated gap between the two

[0053] S4: Aligning the heights of the semiconductor laser chip 1 and the optical chip 2: Adjust the height of the CCD camera 5. When the image of the optical chip 2 is clearest, fix the height of the CCD camera 5. Change the value of the Y-axis of the six-axis displacement stage 3 to move it in the height direction. When the image of the laser chip 1 is clearest, fix the height of the six-axis displacement stage 3. At this time, the upper surfaces of the two chips are at the same height. The camera 5 has been taking images of the upper surface of the optical chip 2. By calculating the gray-scale difference between the pixels in the image, it is judged whether the clearest state has been reached. The specific calculation method of the gray-scale difference is to arrange the gray-scale values of all pixels in the image from largest to smallest, and subtract the gray-scale values of the last 50% from the gray-scale values of the first 50%. The more blurred the image, the smaller the gray-scale difference between the pixels; the clearer the image, the more distinct between black and white, and the larger the difference between the pixels.

[0054] S5: Aligning the semiconductor laser chip 1 and the optical chip 2 in parallel: Change the values of the θX and θZ axes of the six-axis displacement stage 3 to make the images of the semiconductor laser chip 1 all reach the clearest state. At this time, the upper surface of the semiconductor laser is in a plane. Change the value of θY of the six-axis displacement stage 3 so that the illuminated gap between the two chips is a rectangle, and the angle between the two sides of the rectangle is less than 0.1 degrees. At this time, the semiconductor laser chip 1 and the optical chip 2 are in a parallel state.

[0055] S6: Measuring the distance between the semiconductor laser chip 1 and the optical chip 2: Based on the image recognition algorithm, fit the gap between the two chips into a rectangle. According to the number of pixels in the width direction of the rectangle, calculate the actual distance between the two chips. Actual distance = number of pixels × physical size represented by a single pixel.

[0056] S7: Whether the distance is less than the lower limit: Judge whether the distance between the two chips is less than the set lower limit value. If the distance is less than the lower limit, the process terminates abnormally. If the distance is greater than the lower limit, enter the next step S8. The distance between the two chips can be calculated based on the image recognition algorithm or obtained based on the movement amount of the six-axis displacement stage 3 in the Z direction.

[0057] S8: Unidirectionally moving the semiconductor laser chip 1 to the pre-coupling position: The six-axis displacement stage 3 carries the laser chip and moves unidirectionally towards the optical chip 2, and stops moving after reaching the set pre-coupling position.

[0058] S9: Whether the illuminated gap exists: Based on the image recognition algorithm, judge whether the illuminated gap between the two chips exists. If it does not exist, the process terminates abnormally. If it exists, enter the next step.

[0059] S10: Coupling of the semiconductor laser chip 1 and the optical chip 2: Keep the optical chip 2 stationary, and the six-axis displacement stage 3 carries the semiconductor laser chip 1 to move in the X, Y, and Z axis directions so that the power meter 7 collects the maximum optical power value. During the movement and rotation of the displacement stage, the power meter has been collecting the received optical power value. During the adjustment process, the computer always records the correspondence between the position and the power value. After completing the movement in the X, Y, and Z axis directions, it is also necessary to rotate in the directions of θX, θY, and θZ so that the power meter 7 collects the maximum optical power value. After completing the movement and rotation in the three directions, the computer determines the final position of the displacement stage at the X, Y, and Z axis values corresponding to the maximum optical power value, as well as the angle values in the three directions.

[0060] S11: Whether the optical power meets the standard: Determine whether the optical power received by the power meter 7 reaches the set lower limit. If it reaches, end normally. If it does not reach, proceed to the next step.

[0061] S12: Unidirectionally move the semiconductor laser chip 1: The six-axis displacement stage 3 carries the laser chip to move unidirectionally towards the optical chip 2, and stops moving after moving the set distance.

[0062] S13: Whether there is an illuminated gap: Based on the image recognition algorithm, determine whether there is an illuminated gap between the two chips. If not, the process terminates abnormally. If so, proceed to the next step.

[0063] S14: Whether the distance is less than the lower limit: Determine whether the distance between the two chips is less than the set lower limit value. If the distance is less than the lower limit, the process terminates abnormally. If the distance is greater than the lower limit, proceed to the next step. The distance between the two chips can be calculated based on the image recognition algorithm or obtained based on the movement amount of the six-axis displacement stage 3 in the Z direction.

[0064] S15: Abnormal termination: The coupling process ends abnormally, the distance between the two chips is less than the set lower limit value, or there is no illuminated gap between the two chips.

[0065] S16: Normal end: The coupling process ends normally, the distance between the two chips is greater than the set lower limit value, and the optical power is greater than the set lower limit value.

[0066] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0067] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A high-precision end-face coupling device, characterized in that The high-precision end-face coupling device is used for coupling a semiconductor laser chip (1) and an optical chip (2), and includes: A displacement stage (3), the top of which is used to place the semiconductor laser chip (1). The output end of the semiconductor laser chip (1) extends to the outside of one end of the surface of the displacement stage (3) for emitting optical signals. A bracket (4) fixedly arranged on one side of the displacement stage (3), the top of which is used to place the optical chip (2). The input end of the optical chip (2) extends to the outside of one end of the surface of the bracket (4), and the output end extends to the outside of the other end of the surface of the bracket (4). The optical chip (2) is used to receive optical signals. A light source (6) arranged below the semiconductor laser chip (1) and the optical chip (2) for irradiating the gap between the semiconductor laser chip (1) and the optical chip (2). A camera (5) arranged above the semiconductor laser chip (1) and the optical chip (2) for receiving the optical gap image formed by the gap. The optical gap image is used to obtain the real-time distance between the semiconductor laser chip (1) and the optical chip (2), and the semiconductor laser chip (1) and the optical chip (2) are coupled based on the real-time distance. A power meter (7) arranged on the side where the output end of the optical chip (2) is located, used to measure the optical power of the optical signal received by the optical chip (2) during the coupling process, and judge whether the coupling efficiency between the semiconductor laser chip (1) and the optical chip (2) has reached the highest or meets the application requirements according to the optical power.

2. The high-precision end-face coupling device according to claim 1, wherein The displacement stage (3) is a six-axis displacement stage.

3. The high-precision end-face coupling device according to claim 1, characterized in that, The camera (5) is a CCD camera.

4. A coupling method for a high-precision end-face coupling device according to any one of claims 1-3, characterized in that, Including the following steps: Place the semiconductor laser chip (1) and the optical chip (2) on the displacement stage (3) and the bracket (4) respectively. Unidirectionally move the displacement stage (3) to a set initial position, power on the light source (6), and the camera (5) acquires the first image of the laser chip (1), the second image of the optical chip (2), and the optical gap image. Adjust the semiconductor laser chip (1) and the optical chip (2) to the same height based on the first image and the second image. Adjust the semiconductor laser chip (1) and the optical chip (2) to be parallel based on the first image and the optical gap image, and acquire the current first optical gap image. Obtain the current distance between the semiconductor laser chip (1) and the optical chip (2) through the current first optical gap image. If the current distance is greater than the set value, unidirectionally move the semiconductor laser chip (1) to the pre-coupling position, and acquire the current second optical gap image. If there is a gap in the second optical gap image, couple the semiconductor laser chip (1) and the optical chip (2). Measure the optical power after coupling through the power meter (7). If the optical power reaches the set lower limit, the coupling is completed.

5. The coupling method of a high-precision end-face coupling device as described in claim 4, characterized in that, The step of adjusting the semiconductor laser chip (1) and the optical chip (2) to the same height based on the first image and the second image specifically includes the following steps: Adjust the camera (5) in the height direction and acquire the corresponding second images at different heights. Judge the clarity of multiple second images, and fix the camera (5) at the height corresponding to the second image with the highest clarity. Move the displacement stage (3) in the height direction and collect the corresponding first images at different heights; judge the sharpness of multiple first images, and fix the displacement stage (3) at the height corresponding to the first image with the highest sharpness; at this time, the semiconductor laser chip (1) and the optical chip (2) have the same height on the upper surface.

6. The coupling method of a high-precision end-face coupling device as described in claim 5, characterized in that, The step of judging the sharpness of multiple second images specifically includes the following steps: Obtain the gray values of all pixels in multiple second images, and arrange all the gray values in each second image from large to small; Subtract the gray values in the latter 50% from the gray values in the former 50% of the multiple gray values to obtain the sharpness difference of each second image. When the sharpness difference is the largest, the corresponding second image is the clearest; The step of judging the sharpness of multiple first images specifically includes the following steps: Obtain the gray values of all pixels in multiple first images, and arrange all the gray values in each first image from large to small; Subtract the gray values in the latter 50% from the gray values in the former 50% of the multiple gray values to obtain the sharpness difference of each first image. When the sharpness difference is the largest, the corresponding first image is the clearest.

7. The coupling method of a high-precision end-face coupling device according to claim 6, characterized in that, The step of aligning the semiconductor laser chip (1) and the optical chip (2) based on the first image and the optical gap image includes the following steps: Change the values of the θX and θZ axes of the displacement stage (3), and collect multiple first images corresponding to different positions; judge the sharpness of multiple first images, and fix the displacement stage (3) at the position corresponding to the first image with the highest sharpness; Change the value of θY of the displacement stage (3), collect the corresponding multiple optical gap images. If the current optical gap image is a rectangle, the semiconductor laser chip (1) and the optical chip (2) are in a parallel state.

8. The coupling method of a high-precision end-face coupling device as claimed in claim 4, wherein The step of coupling the semiconductor laser chip (1) and the optical chip (2) includes the following steps: Keep the optical chip (2) stationary, and move the displacement stage (3) in the X, Y, and Z axis directions until the power meter collects the maximum optical power value.

9. The coupling method of a high-precision end-face coupling device according to claim 4, characterized in that, It further includes: If the current distance is less than the set value, terminate the coupling; If there is no gap in the second optical gap image, terminate the coupling.

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