CN115683576A - A detection device and method for an optical coupling device - Google Patents

Abstract

The invention relates to a detection device and method for an optical coupling device. The detection device of the optical coupling device includes an optical coupler, a first lens, a second lens, a beam quality analyzer and a processing unit; the optical coupler is used to generate test light, and the first The lens is used to collimate the test light, and the second lens is used to condense the collimated test light; the beam quality analyzer is used to obtain the far-field light distribution of the condensed test light at different optical path positions and send it to the processing unit; the processing unit is used to calculate the far-field light distribution maps at different optical path positions to obtain the angular power change rate of the test light in the far-field propagation. The angular power change rate is used to quantitatively evaluate the mode conversion process in the optical coupling device, without analyzing the internal section, so as to provide a quantitative evaluation standard for the beam shaping ability of the optical coupling device, and also provides a basis for the control of the output mode of the optical coupling device. More reference information.

Description

A detection device and method for an optical coupling device

technical field

The present application relates to the field of semiconductor laser coupling, in particular to a detection device and method for an optical coupling device.

Background technique

Optical couplers and optical waveguide coupling devices represented by photonic lanterns have been widely used in the fields of light combining and light shaping. When using an optical coupling device to obtain a high-power laser, it is generally accompanied by shaping the laser mode to increase the power ratio of the expected mode in the output light. In practical research, the mode shaping performance of optical coupling devices is generally evaluated by evaluating beam quality or beam profile. In this process, nonlinear effects and transverse mode oscillations due to power increase are a serious obstacle to evaluate the energy conversion process occurring in optocoupler devices. However, the performance of the optical coupling device is evaluated by simply evaluating the quality of the output light, and its performance is sensitive to the influence of the environment and bending and twisting conditions, and the mode conversion process in the optical coupling device lacks attention.

Therefore, there is an urgent need for a scheme based on the analysis of the output light to realize the evaluation of the optical coupling process in the optocoupler. This scheme can well describe the mode conversion performance of the optocoupler device and characterize the mode shaping of the optocoupler device. potential. It will reduce the difficulty of optocoupler performance optimization and provide more possibilities for improving the mode conversion efficiency of optocoupler devices.

Contents of the invention

In view of the above problems, the present application provides a detection device and method for an optical coupling device, which solves the problem in the prior art that simply evaluates the output light quality and lacks evaluation of the mode conversion process in the optical coupling device.

To achieve the above object, in a first aspect, the present invention provides a detection device for an optical coupling device, including an optical coupler, a first lens, a second lens, a beam quality analyzer, a sliding assembly and a processing unit; the optical coupler has an output end, the beam quality analyzer has a receiving end, the sliding assembly includes a chute and a slider, the beam quality analyzer is arranged on the slider, and the slider can move in the chute; the optical coupler, the first lens, the second The lens and the beam quality analyzer are arranged in sequence along the direction of the optical path, and the center point of the output end of the optical coupler, the center point of the first lens, the center point of the second lens and the center point of the receiving end of the beam quality analyzer are located on the same central axis , the trough axis of the chute is located in the same vertical plane as the central axis, and the processing unit is electrically connected to the beam quality analyzer;

The optical coupler is used to generate test light, and the test light is sent out through the output end of the optical coupler; the first lens is used to collimate the test light, and the second lens is used to converge the collimated test light; the beam quality The analyzer is used to obtain the far-field light transverse mode pattern distribution diagram of the beamed test light at different optical path positions, and send multiple far-field light distribution diagrams at different optical path positions to the processing unit; the processing unit is used to analyze The far-field light distribution diagrams at different optical path positions are calculated to obtain the angular power change rate of the test light in the far-field propagation.

In some embodiments, the distance between the center point of the first lens and the output end of the optical coupler is within a first preset range.

In some embodiments, a plurality of scale marks are provided on the outer wall of the chute, and the distance between two adjacent scale marks gradually increases along the propagation direction of the optical path according to the first preset gradient, and the scale marks are used to mark the beam quality. The position of the analyzer in the chute.

In some embodiments, the distance between the output end of the optical coupler and the nearest scale mark on the chute is within a second preset range; and/or, the distance between the output end of the optical coupler and the farthest side The distance between the scale line and the second lens is the focal length of the second lens.

In some embodiments, the detection device further includes a flange fixing platform and a flange joint, and the output end of the optical coupler is fixed on the flange fixing platform through the flange joint.

In the second aspect, the present invention also provides a detection method of an optical coupling device, which is applied to the detection device of the optical coupling device described in the first aspect, and the method includes the following steps:

The output terminal of the optocoupler emits test light;

The first lens collimates the test light;

The second lens converges the collimated test light;

The beam quality analyzer obtains the far-field light distribution diagrams of the converged test light at different optical path positions, and sends multiple far-field light distribution diagrams at different optical path positions to the processing unit;

The processing unit calculates the far-field light distribution diagrams at different optical path positions, and obtains the angular power change rate of the test light in the far-field propagation.

In some embodiments, the processing unit calculates the far-field light distribution diagrams at different optical path positions to obtain the angular power change rate of the test light in the far-field propagation, which specifically includes the following steps:

Obtain the far-field light distribution map;

Perform image grayscale processing on the far-field light distribution map to obtain the gray value distribution matrix of the whole image;

Perform the first calculation on the gray value distribution matrix of the whole image to obtain the variance of the angular power distribution;

The second calculation is performed by using the variance of the angular power distribution to obtain the rate of change of the angular power.

In some embodiments, the first calculation is obtained by formula (1), which is as follows:

（1）

(1)

为角功率分布方差，

为不同位置（i）处的远场光分布图的角功率分布方差，

为读取出的灰度矩阵中的数值元素，

为读取出的灰度矩阵中的数值元素平均值，

为灰度值

在灰度矩阵中出现的概率，L为灰度矩阵中元素数目。in,

is the variance of the angular power distribution,

is the angular power distribution variance of the far-field light distribution pattern at different positions (i),

is the numerical element in the read grayscale matrix,

is the average value of the numerical elements in the read grayscale matrix,

is the gray value

The probability of appearing in the grayscale matrix, L is the number of elements in the grayscale matrix.

In some embodiments, the second calculation is obtained by formula (2), which is as follows:

（2）

(2)

为所求输出光在远场传播中的角功率变化率，l、1.5l、2.5l、3.5l为沿光路方向不同位置所对应的相邻刻度线之间的间距，其中l为预设单位距离，

为不同位置（i）处的远场光分布图的角功率分布方差。in,

is the angular power change rate of the output light in the far-field propagation, l , 1.5 l , 2.5 l , and 3.5 l are the distances between adjacent scale marks corresponding to different positions along the optical path direction, where l is the preset unit distance,

is the angular power distribution variance of the far-field light distribution map at different positions (i).

Different from the existing technology, the above technical solution obtains different far-field light distribution diagrams at different positions, and then calculates the angular power change rate according to multiple far-field light distribution diagrams, and uses the angular power change rate to analyze the optical coupling device. The mode conversion process is quantitatively evaluated. The quantitative evaluation specifically includes obtaining the far-field spots at different positions through the CCD, and calculating the variance of the angular power distribution (calculated according to formula (1)) after grayscale processing of the spots. Calculate the variance of the angular power distribution at multiple positions, divide it by the distance difference, and calculate the rate of change of the variance of the angular power distribution with the distance. The obtained parameters can represent the mode conversion process that occurs in the optical coupling device. The larger the value, the higher the proportion of the higher-order mode The higher the value is, the more unstable the mode is, that is, the poorer the ability of the optical coupling device to achieve optical coupling to obtain fundamental mode light. There is no need to analyze internal cut planes, which specifically represent different positions inside the optocoupler device. There is no need to analyze the internal section, that is, it is not necessary to detect the optical field distribution at different positions inside the optical coupling device to analyze the optical coupling process, and the degree of this process can be characterized directly by the variance change rate of the far-field optical field angular power distribution. The greater the rate of change, the worse the ability of the optical coupling device to perform optical coupling to obtain fundamental mode light. So as to provide a quantitative evaluation standard for the beam shaping ability of the optical coupling device, and also provide more reference information for the control of the output mode of the optical coupling device.

The relevant descriptions of the above-mentioned content of the invention are only an overview of the technical solution of the present application. In order to allow those skilled in the art to understand the technical solution of the application more clearly, it can be implemented according to the text of the description and the content recorded in the drawings, and in order to let those skilled in the art The above purpose and other purposes, features and advantages of the present application can be more easily understood, and will be described below in conjunction with specific implementation methods and accompanying drawings of the present application.

Description of drawings

The accompanying drawings are only used to illustrate the principles, implementations, applications, features and effects of specific embodiments of the present invention and other related content, and should not be considered as limiting the present application.

In the accompanying drawings of the manual:

Fig. 1 is a schematic diagram of an optical coupling device detection device according to a specific embodiment of the present invention;

Fig. 2 is a step diagram of the detection method described in the first exemplary embodiment of the present invention;

Fig. 3 is a step diagram of the detection method according to the second exemplary embodiment of the present invention.

The reference signs include: 1, optical coupler; 2, first lens; 3, second lens; 4, beam quality analyzer; 51, chute; 511, scale; 52, slider; 6, flange Fixed platform; D1, the first preset range; D2, the second preset range; D3, the focal length of the second lens; A1, the first distance; A2, the second distance; A3, the third distance; A4, the fourth distance .

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same blocks are denoted by the same reference numerals. With the same reference numerals, their names and functions are also the same. Therefore, its detailed description will not be repeated.

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

Please refer to Fig. 1, in a first aspect, the present invention provides a detection device of an optical coupler 1, comprising an optical coupler 1, a first lens 2, a second lens 3, a beam quality analyzer 4, a sliding assembly and a processing Unit; the optical coupler 1 has an output end, the beam quality analyzer 4 has a receiving end, the sliding assembly includes a chute 51 and a slider 52, the beam quality analyzer 4 is arranged on the slider 52, and the slider 52 can be placed on the chute 51 Inward movement; the optical coupler 1, the first lens 2, the second lens 3, and the beam quality analyzer 4 are sequentially arranged along the optical path direction, and the center point of the output end of the optical coupler 1, the center point of the first lens 2, the second The central point of the lens 3 and the central point of the receiving end of the beam quality analyzer 4 are located on the same central axis, the groove axis of the chute 51 and the central axis are located in the same vertical plane, and the processing unit is electrically connected to the beam quality analyzer 4; The optical coupler 1 is used to generate the test light, and the test light is sent out through the output end of the optical coupler 1; the first lens 2 is used to collimate the test light, and the second lens 3 is used to collimate the test light after collimation Converging; the beam quality analyzer 4 is used to obtain far-field light distribution diagrams of the converged test light at different optical path positions, and send multiple far-field light distribution diagrams at different optical path positions to the processing unit; processing The unit is used to calculate the far-field light distribution diagrams at different optical path positions, and obtain the angular power change rate of the test light in the far-field propagation.

Both the first lens 2 and the second lens 3 are aspheric convex lenses, and the aperture of the first lens 2 is larger than the light field diameter of the test light, and the aperture of the second lens 3 is larger than the light field diameter of the collimated test light . The optical coupler 1 is a device for generating laser beams. The optical coupler 1 can be a fiber coupler or other types of optical coupling devices, as long as the input light is guaranteed to be incident on the first lens 2 in parallel. The central point of the output end of the optical coupler 1, the central point of the first lens 2, the central point of the second lens 3, and the central point of the receiving end of the beam quality analyzer 4 are located on the same central axis, because the light of the test light The axis is located at the central point of the output end of the optical coupler 1 , and the uniform central point of each optical component can ensure that the projected path of the test light does not shift or change, which will affect the subsequent test steps.

The beam quality analyzer 4 is a device for measuring the laser beam, which may be an SP620 beam quality analyzer. The beam profiler 4 can collect the beam image of the laser beam, the beam image includes beam center position, beam peak intensity position, beam divergence, ellipticity, beam intensity uniformity, Gaussian fitting, based on user-selected peak/total energy percentage To form different beam diameters/widths, etc., in this embodiment, the beam quality analyzer 4 is used to obtain the far-field light distribution diagram. The far-field spot generally refers to the lateral optical power distribution pattern detected at a position other than the Rayleigh distance from the laser emission point. Here we use the second lens 3 to shrink the collimated light, and what the CCD detects is the focused far field. field light distribution pattern, and perform subsequent grayscale extraction processing on it.

The far-field light distribution diagram is obtained by receiving the light beam transmitted through the lens twice by the optical coupler 1 at different positions of the beam quality analyzer 4 , and the far-field light distribution diagram at different positions is different. The beam quality analyzer 4 is movably connected with the chute 51 through the slider 52, and the chute 51 is locked on the optical platform. The optical platform is a platform specially used for placing test equipment when studying light, and has a high flatness, ensuring that each The light paths in the instrument are in the same plane. Different positions refer to different positions in the projection direction of the optical path, as shown in Figure 1 specifically, therefore, the groove axis and the central axis of the chute 51 are located in the same vertical plane, and the beam quality analyzer 4 slides in the chute 51 The far-field light distribution diagrams at different positions can be received at the same time, and the central point of the receiving end of the beam quality analyzer 4 can be guaranteed to remain on a central axis during the movement process by setting the chute 51, reducing the far-field light collected. The error of the light distribution map.

By obtaining different far-field light distribution diagrams at different positions, and then calculating the angular power change rate based on multiple far-field light distribution diagrams, the angular power change rate is used to quantitatively evaluate the mode conversion process in one optical coupler. There is no need to analyze the internal section, so as to provide a quantitative evaluation standard for the beam shaping ability of the optical coupler, and also provide more reference information for the control of the output mode of the optical coupler.

Referring to FIG. 1 , in some embodiments, the distance between the center point of the first lens 2 and the output end of the optical coupler 1 is within a first preset range D1 . The first preset range D1 is a comprehensive calculation based on the specific aperture size of the first lens 2 and the light field diameter of the test light emitted by the optical coupler 1 and the range determined after the test. Within the first preset range D1, the test light The optical loss is small, and it is less affected by environmental factors, which ensures the final measurement accuracy of the test light.

Please refer to FIG. 1. In some embodiments, a plurality of scale marks are provided on the outer wall of the chute 51, and the distance between two adjacent scale marks gradually increases along the propagation direction of the optical path according to the first preset gradient. The lines are used to mark the position of the beam profiler 4 in the chute 51 .

The beam quality analyzer 4 needs to obtain the far-field light distribution diagrams at different positions, and for the convenience of distinguishing, it is necessary to mark the far-field light distribution diagrams. Therefore, a scale 511 is provided on the chute 51 for marking different positions. The specific marking method is: according to the output direction of the optical path, the scale 511 is recorded as: the first scale, the second scale, the third scale..., wherein the distance between the first scale and the second scale is recorded as the first scale An interval A1; the interval between the second scale and the third scale is recorded as the second interval A2, and so on. Take five scales as an example, and understand it in conjunction with Figure 1: the five scales correspond to four intervals, which are sequentially recorded as the first interval A1, the second interval A2, the third interval A3, and the fourth interval A4 along the output direction of the optical path; The first interval A1 is smaller than the second interval A2, the second interval A2 is smaller than the third interval A3, and the third interval A3 is smaller than the fourth interval A4, which gradually increases according to the first preset gradient. The specific change value of the first preset gradient is set according to the experimental requirements. In this embodiment, the first distance A1 is set to l , the second distance A2 is set to 1.5 l , and the third distance A3 is set to 2.5 l . The fourth distance A4 is set to 3.5 l , wherein l is a unit distance, and the unit distance can be determined according to the actual size of the detection device.

By setting the scale 511, it is convenient to mark the measurement position of the beam quality analyzer 4, and then it is convenient to record and retrieve the far-field light distribution diagrams at different positions, avoid confusion, and facilitate subsequent far-field light distribution at different positions. Distribution plots for numerical calculations.

Please refer to FIG. 1 , in some embodiments, the distance between the output end of the optical coupler 1 and the nearest scale mark on the chute 51 is within the second preset range D2; and/or, the distance between the output end of the optical coupler 1 The distance between the scale mark on the farthest side of the output end of the output terminal and the second lens 3 is the focal length D3 of the second lens.

The nearest scale mark on the chute 51 is the first scale, the distance between the output end of the optical coupler 1 and the first scale is within the second preset range D2, and the second preset distance is based on the entire optical coupling Optical path distribution of the detector 1 detection device (including the distance between the output end of the optical coupler 1 and the first lens 2, the distance between the second lens 3 and the first lens 2, the distance between the beam quality analyzer 4 and the second lens 3 The distance between) and the comprehensive calculation of the optical field diameter of the test light emitted by the optical coupler 1 and the range determined after the test. In the second preset range D2, the optical loss of the test light is small, ensuring that the final measurement of the test light is accurate To reduce the impact of environmental interference on the measurement results.

The focal length D3 of the second lens is a constant value, and the focal length D3 of the second lens can be obtained by measuring the focal length D3 of the second lens used in actual experiments. When the distance between the scale mark on the side farthest from the output end of the optical coupler 1 and the second lens 3 is the focal length D3 of the second lens, it can be ensured that the beam quality analyzer 4 obtains the farthest far field The light distribution diagram is still a clear pattern, which facilitates the subsequent calculation of different far-field light distribution diagrams.

Please refer to FIG. 1 , in some embodiments, the detection device further includes a flange fixing platform 6 and a flange joint, and the output end of the optical coupler 1 is fixed on the flange fixing platform 6 through the flange joint. The flange fixing platform 6 is a flat plate with a light hole, the optical coupler 1 is locked on the flange fixing platform 6 through the flange joint, and the test light is projected to the first lens 2 through the light hole. Wherein, the flange fixing platform 6 has a threaded hole matching the single-sided SNA-1 flange joint, so as to ensure that the test light can be incident on the collimating lens flatly.

Please refer to Fig. 2, in the second aspect, the present invention also provides a detection method of an optical coupling device, which is applied to the detection device of the optical coupling device described in the first aspect, and the method includes the following steps:

S1. The output end of the optocoupler emits test light;

S2. The first lens collimates the test light;

S3. The second lens converges the collimated test light;

S4. The beam quality analyzer acquires far-field light distribution diagrams of the converged test light at different optical path positions, and sends multiple far-field light distribution diagrams at different optical path positions to the processing unit;

S5. The processing unit calculates a plurality of far-field light distribution maps at different optical path positions to obtain the angular power change rate of the test light in the far-field propagation.

The test light emitted by the optical coupler 1 is divergent, and two adjacent light rays will be farther and farther apart after propagating. Therefore, it is necessary to add the first lens 2 to collimate the test light, and collimation means keeping two adjacent light rays parallel. Convergence In this embodiment, it specifically refers to the process of using a convex lens to focus the collimated laser light so as to obtain the Airy disk at the focal length of the convex lens. Here, the positions for detecting far-field light spots are all within the focal length of the first lens 2 , that is, between the position of the Airy disk and the first lens 2 . This makes the far-field light distribution diagram of the test light clearer and more accurate when it enters the beam quality analyzer 4 .

The beam quality analyzer 4 sequentially obtains different far-field light distribution diagrams at different positions, and sends the far-field light distribution diagrams to the processing unit, and calculates the far-field light distribution diagrams through the processing unit, so as to obtain the test light in the far-field Rate of change of angular power in propagation. As a preferred embodiment, the beam quality analyzer 4 collects the far-field light distribution diagram at positions that are not equidistant, which can increase the accuracy of the results. Collect and draw the corresponding far-field light distribution fitting curve through multiple unequal distance far-field light distribution maps, and then perform the first calculation and the second calculation to obtain the angular power change rate, then this calculation result has smaller performance representation error.

By obtaining different far-field light distribution diagrams at different positions, and then calculating the angular power change rate based on multiple far-field light distribution diagrams, the angular power change rate is used to quantitatively evaluate the mode conversion process in one optical coupler. Quantitative evaluation specifically includes obtaining the far-field spots at different positions through the CCD, and calculating the variance of the angular power distribution (calculated according to formula (1)) after performing grayscale processing on the spots. Calculate the variance of the angular power distribution at multiple positions, divide it by the distance difference, and calculate the rate of change of the variance of the angular power distribution with the distance. The obtained parameters can represent the mode conversion process that occurs in the optical coupling device. The larger the value, the higher the proportion of the higher-order mode The higher the value is, the more unstable the mode is, that is, the poorer the ability of the optical coupling device to achieve optical coupling to obtain fundamental mode light. There is no need to analyze internal cut planes, which specifically represent different positions inside the optocoupler device. There is no need to analyze the internal section, that is, it is not necessary to detect the optical field distribution at different positions inside the optical coupling device to analyze the optical coupling process, and the degree of this process can be characterized directly by the variance change rate of the far-field optical field angular power distribution. The greater the rate of change, the worse the ability of the optical coupling device to perform optical coupling to obtain fundamental mode light. So as to provide a quantitative evaluation standard for the beam shaping ability of the optical coupler, and also provide more reference information for the control of the output mode of the optical coupler.

Please refer to FIG. 3. In some embodiments, the processing unit calculates the far-field light distribution diagrams at different optical path positions to obtain the angular power change rate of the test light in the far-field propagation, which specifically includes the following steps:

S51. Obtain a far-field light distribution map;

S52. Perform image grayscale processing on the far-field light distribution map to obtain a distribution matrix of grayscale values in the entire image;

S53. Perform a first calculation on the gray value distribution matrix of the whole image to obtain a variance of angular power distribution;

S54. Perform a second calculation using the angular power distribution variance to obtain the angular power change rate.

Image grayscale processing specifically includes: performing 16-bit grayscale processing on the far-field light distribution map through a preset program, and extracting the gray value distribution matrix of the entire image. The size of the gray value distribution matrix of the entire image generally does not exceed the optical power fitted by the software Distribute the range of the square aperture; when there is a large amount of repeated data in the edge of the gray value distribution matrix of the whole image, it needs to be removed. Extract L effective gray values from the gray value distribution matrix of the whole image for the first calculation. It should be noted here that the number L of effective gray values is not equal to that in the gray value distribution matrix of the entire image The number of grayscale values, and the range of effective grayscale values generally does not exceed the range of the optical power distribution circular aperture fitted by the software in the grayscale matrix. It should be noted that if the change rate of the variance of the angular power distribution is significantly lower than the normal data of the test light at the same wavelength and the same power, it is necessary to narrow the value range of the effective gray value for recalculation.

After the angular power distribution variance is obtained through the first calculation, a second calculation is performed on the plurality of angular power distribution variances to obtain the angular power change rate. Through the above method steps, the mode conversion performance of an optocoupler can be well described, the mode shaping potential of an optocoupler can be characterized, the difficulty of optimizing the performance of an optocoupler can be reduced, and the mode conversion efficiency of an optocoupler can be improved. Provide more possibilities.

The rate of change of angular power obtained by the above steps will be better than the rate of change of angular power obtained by simple average solution.

In some embodiments, the first calculation is obtained by formula (1), which is as follows:

（1）

(1)

为角功率分布方差，

为不同位置（i）处的远场光分布图的角功率分布方差，

为读取出的灰度矩阵中的数值元素，

为读取出的灰度矩阵中的数值元素平均值，

为灰度值

在灰度矩阵中出现的概率，L为灰度矩阵中元素数目。in,

is the variance of the angular power distribution,

is the angular power distribution variance of the far-field light distribution pattern at different positions (i),

is the numerical element in the read grayscale matrix,

is the average value of the numerical elements in the read grayscale matrix,

is the gray value

The probability of appearing in the grayscale matrix, L is the number of elements in the grayscale matrix.

In some embodiments, the second calculation is obtained by formula (2), which is as follows:

（2）

(2)

为所求输出光在远场传播中的角功率变化率，l、1.5 l、2.5 l、3.5 l为沿光路方向不同位置所对应的相邻刻度线之间的间距，其中l为预设单位距离，

不同位置（i）处的远场光分布图的角功率分布方差。in,

is the angular power change rate of the output light in the far-field propagation, l , 1.5 l , 2.5 l , and 3.5 l are the distances between adjacent scale marks corresponding to different positions along the optical path direction, where l is the preset unit distance,

Angular power distribution variance of the far-field light profile at different positions (i).

Specific examples:

The test light is generated by an optocoupler with a 3x1 photon lantern, which is a 976nm laser. The light output by the optocoupler is a stable optical mode, and the power jitter does not exceed ±0.1%. The first lens is an aspheric convex lens with a focal length less than 30mm. For example, the focal length of the first lens can be 25mm or 20mm; the first lens collimates the output light of the optical coupling device, and the optical coupler is arranged on the flange through a flange joint. On the fixed platform, the flange fixed platform uses a fiber coupler fixed platform with SNA-1 flange matching threaded holes, where the output end of the optical coupler is located at the focus position of the first lens.

The focal length of the second lens is 200mm, and it is set behind the first lens (that is, the output direction of the light after passing through the first lens). The second lens is used to amplify the test light, so that the beam quality analyzer can obtain clearer light. field distribution map. The beam quality analyzer adopts the beam quality analyzer model SP620. The beam quality analyzer is used to capture the far-field light pattern, and transmit the lossless far-field light distribution map to the processing unit, which is a computer terminal or other computer equipment. The SP620 beam quality analyzer uses a far-field lens without magnification. Filters can be added according to the output light power to avoid light saturation in the pattern and ensure the quality of the far-field light distribution map.

The chute is a base plate with standard scales and grooves, with threaded holes on both sides for fixing to an optical table. The upper groove is used for fixing and sliding of the beam quality analyzer, so as to ensure that the lens center of the beam quality analyzer is always located on the central axis of the second lens. Among them, the first preset distance is 30mm, the second preset distance is 80mm, and the second preset distance can be verified by experiments to obtain stable light that can be completely captured by the CCD lens (the lens in the beam quality analyzer) The power distribution pattern of the transverse mode field (that is, the far-field light distribution diagram) shall prevail. Here it represents the far-field transverse mode spot, or it may be expressed as the power distribution state of the far-field light on the transverse interface, and the distance is generally less than 80mm. The distance from the first scale to the end face of the chute close to the optical coupler is 10mm. The test light is collimated by the first lens and then input to the second lens. After being enlarged by the second lens, it is input to the far-field lens of beam quality analyzer SP620. The far-field light captured by the lens is fed into a computer program for subsequent processing.

Among them, the distance between two adjacent standard scales of the chute along the propagation direction of the optical path is respectivelyl, 1.5l, 2.5 l, 3.5l, more non-equidistant scales can increase the reliability of the results.

The SP620 beam quality analyzer performs noise reduction processing on the collected far-field light distribution diagram. The far-field light distribution diagram input into the program is the standard rainbow color, and the noise reduction uses the gain adjustment that comes with the beam quality analyzer. Through the image grayscale processing and grayscale matrix extraction of the processing unit, the far-field light distribution map is processed into a 16-bit grayscale image using python, and the grayscale value matrix is extracted to obtain a 16-bit grayscale value. The program based on formula (1) realizes the solution of angular power distribution variance of multiple images. The angular power distribution variance uses the grayscale variance formula. The angular power change rate is obtained based on the first calculation result of formula (1) and the second calculation of formula (2). Using curve fitting based on more data to solve the variance rate of angular power distribution is better than simple mean value. The far-field light distribution diagram used to analyze the variation rate of the variance of the angular power distribution The furthest distance from the output end of the optical coupler does not exceed 300mm.

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

The above specific implementation manners of the present invention do not constitute a limitation to the protection scope of the present invention. Any other corresponding changes and modifications made according to the technical concept of the present invention shall be included in the protection scope of the claims of the present invention.

Claims (9)

1. A detection device for an optical coupling device, comprising an optical coupler, a first lens, a second lens, a beam quality analyzer, a sliding assembly and a processing unit; The optical coupler has an output end, the beam quality analyzer has a receiving end, the sliding assembly includes a chute and a slider, the beam quality analyzer is arranged on the slider, and the slider can be Move in the chute; The optical coupler, the first lens, the second lens, and the beam quality analyzer are arranged in sequence along the optical path direction, and the center point of the output end of the optical coupler, the center point of the first lens, the center point of the second lens, and The center point of the receiving end of the beam quality analyzer is located on the same central axis, the trough axis of the chute is located in the same vertical plane as the central axis, and the processing unit is electrically connected to the beam quality analyzer ; The optical coupler is used to generate test light, and the test light is emitted through the output end of the optical coupler; The first lens is used to collimate the test light, and the second lens is used to converge the collimated test light; The beam quality analyzer is used to obtain far-field light distribution diagrams of the converged test light at different optical path positions, and send multiple far-field light distribution diagrams at different optical path positions to the processing unit; The processing unit is used to calculate the far-field light distribution diagrams at different positions of the optical path to obtain the angular power change rate of the far-field transverse mode pattern of the test light during propagation. 2 . The detection device of an optical coupling device according to claim 1 , wherein the distance between the center point of the first lens and the output end of the optical coupler is within a first preset range. 3 . 3. The detection device of an optical coupling device according to claim 1 or 2, wherein a plurality of scale marks are also arranged on the outer wall of the chute, and the distance between two adjacent scale marks propagates along the optical path The direction gradually increases according to a first preset gradient, and the scale line is used to mark the position of the beam quality analyzer in the chute. 4. The detection device of an optical coupling device according to claim 2, wherein the distance between the output end of the optical coupler and the nearest scale mark on the chute is within a second preset range ; And/or, the distance between the scale line on the side farthest from the output end of the optical coupler and the second lens is the focal length of the second lens. 5. The detection device of an optical coupling device according to claim 1, further comprising a flange fixing platform and a flange joint, and the output end of the optical coupler is fixed on the flange by a flange joint. on the platform. 6. A detection method of an optical coupling device, characterized in that, it is applied to the detection device of the optical coupling device according to any one of claims 1-5, said method comprising the following steps: The output terminal of the optocoupler emits test light; the first lens collimates the test light; The second lens converges the collimated test light; The beam quality analyzer acquires far-field light distribution diagrams of the converged test light at different optical path positions, and sends multiple far-field light distribution diagrams at different optical path positions to the processing unit; The processing unit calculates the far-field light distribution diagrams at different positions of the optical path to obtain the angular power change rate of the test light in the far-field propagation. 7. The detection method of an optical coupling device according to claim 6, wherein the processing unit calculates the far-field light distribution diagrams at different optical path positions to obtain the test light in the far-field propagation The rate of change of angular power, specifically includes the following steps: Obtain the far-field light distribution diagram; performing image grayscale processing on the far-field light distribution map to obtain a gray value distribution matrix of the whole image; performing a first calculation on the full-image gray value distribution matrix to obtain a variance of angular power distribution; The second calculation is performed by using the variance of the angular power distribution to obtain the rate of change of the angular power. 8. The detection method of an optical coupling device according to claim 7, wherein the first calculation is obtained by formula (1), and the formula (1) is as follows:

(1) in,

is the variance of the angular power distribution,

is the angular power distribution variance of the far-field light distribution pattern at different positions (i),

is the numerical element in the read grayscale matrix,

is the average value of the numerical elements in the read grayscale matrix,

is the gray value

The probability of appearing in the grayscale matrix, L is the number of elements in the grayscale matrix. 9. The detection method of an optical coupling device according to claim 8, wherein the second calculation is obtained by formula (2), and the formula (2) is as follows:

(2) in,

is the angular power change rate of the output light in the far-field propagation, l , 1.5 l , 2.5 l , and 3.5 l are the distances between adjacent scale marks corresponding to different positions along the optical path direction, where l is the preset unit distance,

is the angular power distribution variance of the far-field light distribution map at different positions (i).

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