Optical module coupling method

Abstract

The invention relates to the technical field of optical communication, and provides an optical module coupling method, which comprises the following steps: S1, establishing a light spot distribution model according to each measured optical power value, S2, optimizing the alignment process of an optical element and a laser by combining the light spot distribution model, and finely adjusting the position of the optical element in an area with the highest light spot brightness, s3, dispensing and fixing the optical element, and S4, completing coupling. According to the optical module coupling method, the light spot distribution model is established and combined with the light spot distribution model to complete alignment, fine adjustment, alignment and other processes, so that the optimal coupling position is determined, the coupling efficiency and the signal integrity are improved, and the transmission loss is reduced.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to an optical module coupling method. Background Art

[0002] Optical module coupling generally refers to the process of efficiently transmitting and aligning the optical signal emitted by a light source (such as a laser) to an optical fiber or photodetector through an optical element (such as a lens) to ensure effective transmission and reception of the optical signal. The light emission path of a laser is abstractly an inverted "peak" shape that diverges in a specific direction, and the energy density is higher as it is closer to the center.

[0003] The intensity of the optical signal in the optical module system, which is coupled to the optical fiber (transmitter coupling) and focused and coupled to the optical fiber by the lens, is a direct and effective indicator for measuring coupling efficiency. High optical power means that more optical signals are successfully transmitted, indicating that the coupling efficiency is high. If the alignment accuracy is insufficient during the coupling process or the light beam is not fully focused on the fiber core, the output optical power will be significantly reduced. Therefore, the alignment and the focal length position of the lens need to be adjusted to obtain the maximum optical power.

[0004] When an external light source is coupled to the photodetector (receiving end coupling) of the optical module system, the responsivity measures the effect of converting the optical signal received by the system into an electrical signal, reflecting the effectiveness of the entire optical coupling link. A higher responsivity means that the transmission and reception of optical power is more efficient, which directly affects the communication performance of the optical module. Therefore, in production, the responsivity can be measured to determine whether the coupling is qualified.

[0005] In actual production, the optical power distribution under different spatial coordinates will be monitored in real time when the transmitting end is coupled, and the responsivity distribution under different spatial coordinates will be monitored in real time when the receiving end is coupled. Generally, after determining the appropriate height (Z axis), a curve of the horizontal axis (X axis) coordinate and the optical power value (a flat-top curve with an opening downward) will be drawn to determine the appropriate X-axis coordinate (the middle of the flat-top interval), and the appropriate Y-axis coordinate will be determined in the same way. Generally, under the premise of qualified indicators, the order of determining the three axes is not strictly defined.

[0006] The above-mentioned method of determining the coupling position by a single optical power and response value has the following problems: the coupling of the array optical chip may lose the coupling performance of the uncertain channel; it is impossible to judge the abnormal status of the laser, optical elements and optical fiber; it is impossible to determine the laser light divergence angle and the optimal coupling distance; and it is impossible to obtain the dynamic indicators of the coupling system.

[0007] In addition, in the application of 400 / 800G COB (Chip On Board) packaged multi-mode optical modules, the characteristics of the light spot during coupling have a great impact on the performance of the entire system. Previous technologies were unable to present the quality of the light spot and optical path during coupling. Summary of the invention

[0008] The object of the present invention is to provide an optical module coupling method, which can at least solve some of the defects in the prior art.

[0009] To achieve the above object, an embodiment of the present invention provides the following technical solution: an optical module coupling method, comprising the following steps:

[0010] S1, establish a spot distribution model based on the measured optical power values,

[0011] S2, optimizing the alignment process between the optical element and the laser in combination with the light spot distribution model, and fine-tuning the position of the optical element in the area with the highest light spot brightness until the light spot has a normal shape and the center is aligned with the core of the optical fiber,

[0012] S3, glue fixation of optical components,

[0013] S4, coupling is completed.

[0014] Furthermore, in the S1 step, the optical system is placed on the alignment system, the optical element is moved along the X-axis direction and the Y-axis direction, the optical power at each position is measured using an optical power meter, and all the measured optical power values ​​are recorded and paired with the corresponding XY-axis position coordinates of the optical element.

[0015] Furthermore, in the S1 step, after recording in the X-axis and Y-axis directions, the optical element is moved along the Z-axis direction, and the optical power at each position is measured using an optical power meter. All the measured optical power values ​​are recorded and paired with the corresponding optical element Z-axis position coordinates.

[0016] Furthermore, each measured optical power value is processed, and a distribution morphology diagram of the optical power is drawn, and the distribution morphology diagram is converted into a heat map.

[0017] Further, the center position of the light spot is identified according to the distribution morphology diagram or the heat map.

[0018] Furthermore, in the heat map, different colors represent different optical power values, and the light spot of the laser is distributed in a Gaussian shape.

[0019] Furthermore, Gaussian fitting is used to fit the distribution morphology diagram to obtain accurate spot center, spot radius and spot divergence angle, and measurement noise is eliminated during the fitting process to obtain an accurate spot distribution model.

[0020] Furthermore, the alignment system is a six-degree-of-freedom alignment system with micron-level precision.

[0021] Furthermore, the alignment system is an automatic alignment system, and the automatic alignment system automatically optimizes the alignment process between the optical element and the laser in combination with the light spot distribution model.

[0022] Furthermore, a feedback algorithm is used to fine-tune the position of the optical element in the area with the highest brightness of the light spot until the light spot has a normal shape and its center is aligned with the core of the optical fiber.

[0023] Compared with the prior art, the beneficial effects of the present invention are: a method for coupling an optical module, by establishing a light spot distribution model and combining the light spot distribution model to complete alignment, fine-tuning and alignment processes to determine the optimal coupling position, thereby improving coupling efficiency and signal integrity and reducing transmission loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention provides a flowchart of an optical module coupling method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0026] See also Figure 1 , an embodiment of the present invention provides an optical module coupling method, comprising the following steps: S1, establishing a spot distribution model according to each measured optical power value, S2, optimizing the alignment process of the optical element and the laser in combination with the spot distribution model, and fine-tuning the position of the optical element in the area with the highest spot brightness until the spot shape is normal and the center is aligned with the optical fiber core, S3, dispensing glue to fix the optical element, S4, completing the coupling. In this embodiment, by establishing a spot distribution model, and completing alignment, fine-tuning and alignment processes in combination with the spot distribution model, the optimal coupling position is determined, the coupling efficiency and signal integrity are improved, and the transmission loss is reduced. Specifically, in the VCSEL (vertical cavity surface emitting laser) coupling process, the distribution of the laser spot can be plotted by measuring the value of the optical power. This method can help confirm whether the alignment between the optical fiber core and the spot is accurate, and evaluate the shape, size and distribution of the spot on the end face of the optical fiber. The establishment of the spot distribution model can be established by multiple dimensions, such as the X-axis, the Y-axis and the Z-axis. The specific establishment method is: place the optical system on the alignment system, move the optical element along the X-axis and Y-axis directions, use an optical power meter to measure the optical power at each position, and record all the measured optical power values ​​and pair them with the corresponding XY-axis position coordinates of the optical element.

[0027] Preferably, the optical system can be placed on a six-degree-of-freedom alignment platform with micron-level precision, the laser end is fixed, the lens is moved along the X-axis and Y-axis (keeping the Z-axis fixed), the scanning area should cover the entire range of the spot, and the optical power at each position is measured using an optical power meter. All measured optical power values ​​are recorded and paired with the corresponding lens position coordinates (X, Y). The software control system can automatically generate a data set. Preferably, when measuring optical power, the use of narrow-core optical fibers improves the measurement accuracy of optical power in spatial position. The measurement should be stopped in the area where the optical power remains unchanged, and the distribution of the spot in this area is obtained by simulation. Preferably, when the distance of the moving lens is greater than the diameter of the optical fiber core and the optical power does not change near the light point, the recording of the optical power value stops. Preferably, the spot distribution model can be used to evaluate the alignment of the spot center with the optical fiber core, analyze the spot size and shape, and analyze the influence of power distribution on optical fiber coupling. In the coupling process, this embodiment uses the spatial distribution of optical power to image the spot in three dimensions, analyzes the size, shape, divergence angle, alignment and other indicators of the spot, and determines the optimal coupling position. The coupling efficiency and signal integrity of the system are improved, and the transmission loss is reduced. Visualizing the spot in two dimensions enables determination of the location of the array's optimal energy distribution for coupling.

[0028] To further optimize the above scheme, in the step S1, after recording in the X-axis direction and the Y-axis direction, move the optical element along the Z-axis direction, use an optical power meter to measure the optical power at each position, and record all the measured optical power values ​​and pair them with the corresponding optical element Z-axis position coordinates. After the above two-dimensional optical power measurement is completed, measure the Z-axis direction to obtain a three-dimensional optical power distribution. Through the Gaussian distribution model and the collected data, the spot distribution in the space without optical power change is simulated, and a complete spot model is generated in combination with the change space. Visualizing the spot in three dimensions can determine various parameters to deduce the complete spot model.

[0029] As an optimization scheme of the embodiment of the present invention, the measured optical power values ​​are processed, and a distribution morphology diagram of the optical power is drawn, and the distribution morphology diagram is converted into a heat map. The center position of the light spot can be identified through the distribution morphology diagram or the heat map. In this embodiment, the two-dimensional optical power value is processed to obtain a two-dimensional distribution morphology diagram, which can be converted into a heat map (heatmap), with different colors representing different optical power values, and the laser spot is distributed in a Gaussian shape. Adjust the coupling position and update the two-dimensional distribution morphology diagram in real time until the center of the array light spot and the core of the array optical element are maximized to ensure the best coupling effect of the array. By observing the shape of the two-dimensional distribution morphology diagram, it can be determined whether the light spot is approximately circular. If the shape of the light spot deviates from the circle (irregular shape), it may indicate that there is a problem with the laser light emission or that the coupling angle is incorrect. By analyzing the two-dimensional distribution morphology diagram, the uniformity of the light spot distribution can be identified. Mottled or asymmetric light spot morphology generally implies a high-order mode. Add the optical power value in the Z-axis direction and process it to obtain a three-dimensional distribution morphology diagram. Specifically, the measured two-dimensional optical power distribution data of different Z axes are processed into three dimensions. The light spot under the three-dimensional distribution morphology diagram usually appears as a "peak", which is similar to a Gaussian or bell-shaped curve. The three-dimensional distribution morphology diagram can help determine the overall divergence angle of the light spot and the rate of power decline, thereby inferring the light spot distribution morphology in the area where the optical power measurement has not changed.

[0030] As an optimization solution of the embodiment of the present invention, the ambient temperature and the laser current are changed to obtain the light spot model under different conditions. In this embodiment, a more perfect light spot model is generated in combination with the change space.

[0031] As an optimization scheme of the embodiment of the present invention, Gaussian fitting is used to fit the distribution morphology diagram to obtain accurate spot center, spot radius and spot divergence angle, and measurement noise is eliminated during the fitting process to obtain an accurate spot distribution model. In this embodiment, a statistical analysis method such as Gaussian fitting is used to fit the power distribution diagram to obtain more accurate parameters such as spot center, radius and divergence angle. The fitting process can eliminate measurement noise and provide a more accurate spot distribution model.

[0032] As an optimization scheme of an embodiment of the present invention, the alignment system is an automatic alignment system, and the automatic alignment system automatically optimizes the alignment process of the optical element and the laser in combination with the light spot distribution model. Preferably, a feedback algorithm is used to fine-tune the position of the optical element in the area with the highest light spot brightness until the light spot shape is normal and the center is aligned with the optical fiber core. In this embodiment, the automatic alignment system can automatically optimize the alignment process of the optical element and the laser in combination with the optical power distribution data, and the automatic alignment system uses a linear drive mechanism to drive the lens to move. Through the feedback algorithm, the position of the lens is automatically fine-tuned in the area with the highest light spot brightness until the light spot shape is normal and the center is completely aligned with the optical fiber core, and the normal shape of the light spot is a circle, wherein the feedback algorithm specifically visually identifies the shape of the light spot and measures the current optical power value, and assigns different weights and qualification standards to the coupling results to achieve the best coupling effect.

[0033] As an optimization scheme of the embodiment of the present invention, the optical device is fixed by glue at the position where various parameters are optimal to complete the coupling. In this embodiment, by measuring the optical power at each point, the distribution of the light spot can be plotted. With the help of automated equipment and data processing algorithms, abnormalities are analyzed to maximize coupling accuracy and efficiency. Similarly, the spatial distribution of the receiving end responsivity plots the distribution of the incident light spot to achieve effective coupling.

[0034] As an optimization solution of the embodiment of the present invention, in the method of measuring the light spot, a cover area can be added to the end face of the narrow diameter optical fiber to achieve slit measurement. A lens can be used to amplify the light spot so as to achieve more accurate measurement. A larger area light sensor can be used to capture the light spot image, which shows the spatial distribution and intensity distribution of the light spot.

[0035] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An optical module coupling method, characterized in that: The steps include: S1, establish a spot distribution model based on the measured optical power values, S2, optimizing the alignment process between the optical element and the laser in combination with the light spot distribution model, and fine-tuning the position of the optical element in the area with the highest light spot brightness until the light spot has a normal shape and the center is aligned with the core of the optical fiber, S3, glue fixation of optical components, S4, coupling is completed.

2. The optical module coupling method according to claim 1, wherein: In the S1 step, the optical system is placed on the alignment system, the optical element is moved along the X-axis direction and the Y-axis direction, the optical power at each position is measured using an optical power meter, and all the measured optical power values ​​are recorded and paired with the corresponding XY-axis position coordinates of the optical element.

3. The optical module coupling method according to claim 2, wherein: In the S1 step, after recording in the X-axis and Y-axis directions, the optical element is moved along the Z-axis direction, and the optical power at each position is measured using an optical power meter. All measured optical power values ​​are recorded and paired with the corresponding optical element Z-axis position coordinates.

4. An optical module coupling method according to any one of claims 1 to 3, characterized in that: The measured optical power values ​​are processed, and a distribution morphology diagram of the optical power is drawn, and the distribution morphology diagram is converted into a heat map.

5. The optical module coupling method according to claim 4, characterized in that: The center position of the light spot is identified according to the distribution morphology diagram or the heat map.

6. The optical module coupling method according to claim 4, characterized in that: In the heat map, different colors represent different optical power values, and the light spot of the laser is distributed in a Gaussian shape.

7. The optical module coupling method according to claim 4, characterized in that: Gaussian fitting is used to fit the distribution morphology diagram to obtain accurate spot center, spot radius and spot divergence angle, and measurement noise is eliminated during the fitting process to obtain an accurate spot distribution model.

8. The optical module coupling method according to claim 2, characterized in that: The alignment system is a six-degree-of-freedom alignment system with micron-level precision.

9. The optical module coupling method according to claim 2, characterized in that: The alignment system is an automatic alignment system, and the automatic alignment system automatically optimizes the alignment process between the optical element and the laser in combination with the light spot distribution model.

10. The optical module coupling method according to claim 1, characterized in that: A feedback algorithm is used to fine-tune the position of the optical element in the area with the highest brightness of the light spot until the light spot has a normal shape and the center is aligned with the core of the optical fiber.

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