Constant-temperature optical fiber coupling table alignment equipment and use method thereof

Abstract

The invention discloses constant-temperature optical fiber coupling table alignment equipment and a use method thereof. The constant-temperature optical fiber coupling table alignment equipment comprises a coupling table, a four-axis objective table and an optical fiber clamping piece, wherein the four-axis objective table and the optical fiber clamping piece are arranged on the coupling table; an optical device to be coupled into an optical fiber is arranged on the four-axis objective table; the optical fiber clamping piece is used for fixing the head end of an optical fiber to be coupled; the alignment light path and the auxiliary light path are used in cooperation, the industrial camera is used for obtaining the position of the light spot emitted to the surface of the target piece by the auxiliary light path, and then the optimal adjustment path from the coordinates of the light spot to the datum point is calculated, so that the four-axis objective table is controlled to adjust the position and angle of the optical device; light of the optical device is vertically emitted into the coupling end face of the to-be-coupled optical fiber through the first lens. Compared with the prior art, the difficulty of monitoring the position of the light on the optical fiber coupling end face is reduced, automatic adjustment can be achieved, the light can vertically enter the optical fiber coupling end face, and it is ensured that the loss of the light coupled into the optical fiber is minimum and the efficiency is high.

Description

Technical Field

[0001] The present invention relates to the technical field of optical modules, and in particular to a constant temperature optical fiber coupling station alignment device and a use method thereof. Background Art

[0002] An optical module is composed of optoelectronic devices, functional circuits and optical interfaces. Optoelectronic devices include two parts: transmitting and receiving. Simply put, the function of an optical module is to convert electrical signals into optical signals at the transmitting end, and then convert the optical signals into electrical signals at the receiving end after being transmitted through optical fibers.

[0003] The bottleneck process of the optical module production process is the efficiency of the coupling process. At present, this process requires the PCBA (after chip mounting and gold wire bonding) to be placed on the coupling table for clamping and stabilization, the gold finger end is powered through the connector, the optical fiber is inserted into the lens for alignment, and the other end is connected to the optical power meter or laser. In this process, the equipment needs to first confirm the XY and two angle slides where the PCBA is placed to ensure the flatness and angle of the PCBA, and then through the four axial movements of XYZA, ensure the fit of the lowered lens and PCBA and the accurate position of the light hole and optical fiber.

[0004] However, it is difficult for existing coupling devices to quickly and accurately align the light source with the coupling end face of the optical fiber. The light cannot be vertically injected into the coupling end face of the optical fiber, and the signal-to-noise ratio is low and cannot meet the use requirements.

[0005] Therefore, it is necessary to provide a constant temperature optical fiber coupling stage alignment device and a method of using the same to solve the above technical problems. Summary of the invention

[0006] The invention overcomes the shortcomings of the prior art and provides a constant temperature optical fiber coupling stage alignment device and a use method thereof.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a constant temperature optical fiber coupling stage alignment device, comprising:

[0008] Coupling station,

[0009] A four-axis stage and an optical fiber clamping member disposed on the coupling platform;

[0010] An optical device to be coupled into the optical fiber is arranged on the four-axis stage;

[0011] The optical fiber clamp is used to fix the head end of the optical fiber to be coupled;

[0012] The coupling platform further comprises: an alignment optical path arranged between the optical device and the optical fiber to be coupled, and an auxiliary optical path arranged perpendicular to the alignment optical path; the alignment optical path comprises: a collimator, a beam splitter and a first lens arranged in sequence on the optical axis of the optical device; the auxiliary optical path comprises: a second lens and a target arranged on the reflection optical path of the beam splitter;

[0013] Also included is a position detection system for detecting the coordinates of the light spot on the surface of the target;

[0014] It also includes an automatic control system, which controls the four-axis stage to adjust the position and angle of the optical device according to the light spot coordinates output by the position detection system, so that the light of the optical device is vertically incident on the coupling end face of the optical fiber to be coupled through the first lens;

[0015] An optical power meter is also included, and the other end of the optical fiber to be coupled is connected to the optical power meter.

[0016] In a preferred embodiment of the present invention, the first lens is arranged on the projection light path of the beam splitter, and the coupling section of the optical fiber to be coupled is arranged at the focus of the first lens.

[0017] In a preferred embodiment of the present invention, the focus of the second lens is on the surface of the target.

[0018] In a preferred embodiment of the present invention, a cross reference mark is provided at the center of the target.

[0019] In a preferred embodiment of the present invention, the position detection system comprises: an industrial camera and a light spot centroid position calculation module;

[0020] The industrial camera captures the position of the light spot on the surface of the target;

[0021] The light spot centroid position calculation module includes:

[0022] A centroid determination unit, which calculates the centroid of the light spot by edge detection based on the position of the light spot on the target surface;

[0023] A centroid position calculation unit; establishes a cross coordinate axis according to the target reference, and determines the coordinate information of the light spot centroid according to the light spot centroid calculated by the centroid determination unit.

[0024] In a preferred embodiment of the present invention, the automatic control system comprises:

[0025] An adjustment path analysis module is configured to analyze an optimal adjustment path from the current light spot coordinates to the target coordinates according to the light spot coordinates on the auxiliary light path output by the position detection system;

[0026] The automatic control module controls the four-axis stage to adjust the position and angle of the optical device according to the optimal adjustment path output by the adjustment path analysis module, so that the light of the optical device is vertically incident on the coupling end face of the optical fiber to be coupled through the first lens.

[0027] In a preferred embodiment of the present invention, a constant temperature module is further included, and the constant temperature module is used to control the temperature of the coupling platform within a set range.

[0028] A method for using a constant temperature optical fiber coupling stage alignment device comprises the following steps:

[0029] S1. Setting a reference point at the center of the target surface and establishing a rectangular coordinate system, wherein the reference point is the origin of the coordinate system and corresponds to the coupling end surface of the optical fiber to be coupled;

[0030] S2. The light emitted by the optical device is collimated by the collimator and then divided into transmitted light and reflected light by the beam splitter. The reflected light will be reflected to the second lens, and the focus of the second lens is concentrated on the surface of the target;

[0031] S3, taking a target surface image through an industrial camera to obtain the light spot coordinates;

[0032] S4. Calculate the optimal adjustment path from the light spot coordinates to the reference point to control the four-axis stage to adjust the position and angle of the optical device so that the light of the optical device passes through the first lens and vertically enters the coupling end face of the optical fiber to be coupled.

[0033] In a preferred embodiment of the present invention, the calculation of the light spot coordinates includes the following steps:

[0034] S31, preprocessing the image captured by the industrial camera;

[0035] S32, using an edge detection algorithm to extract the light spot boundary and separate the light spot area from the background;

[0036] S33, by traversing all the pixel points belonging to the light spot in the image, calculating the average value of the coordinates of these pixel points, and obtaining the centroid position of the light spot.

[0037] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0038] (1) The present invention provides a constant temperature optical fiber coupling stage alignment device and a method for using the device. By using the alignment optical path and the auxiliary optical path together, and using an industrial camera to obtain the position of the light spot emitted by the auxiliary optical path to the target surface, and then calculating the optimal adjustment path from the light spot coordinate to the reference point, the four-axis stage is controlled to adjust the position and angle of the optical device, so that the light of the optical device passes through the first lens and vertically enters the coupling end face of the optical fiber to be coupled. Compared with the prior art, the present invention reduces the difficulty of monitoring the position of the light at the optical fiber coupling end face, and can realize automatic adjustment, so that the light can be vertically injected into the optical fiber coupling end face, ensuring that the light loss coupled into the optical fiber is minimal and the efficiency is high.

[0039] (2) The present invention sets a target so that the light passing through the beam splitter is incident on the surface of the target. The target is non-reflective and has extremely high flatness. The position of the light spot on the surface of the target can be clearly obtained by an industrial camera, and the centroid position of the light spot can be obtained by edge detection and calculation, thereby improving the accuracy of the light spot position. Compared with the prior art, in which the light spot obtained by the industrial camera is a circular area, the present invention further determines the light spot position at a point, thereby improving the accuracy of the coupling alignment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 is a structural diagram of an alignment optical path and an auxiliary optical path of a preferred embodiment of the present invention;

[0042] Figure 2 is a diagram of a method for using a constant temperature optical fiber coupling station alignment device according to a preferred embodiment of the present invention;

[0043] In the figure: 1. Optical device; 2. Collimator; 3. Beam splitter; 4. First lens; 5. Second lens; 6. Target; 7. Industrial camera; 8. Optical fiber to be coupled. DETAILED DESCRIPTION

[0044] 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.

[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0046] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, "multiple" means two or more.

[0047] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0048] like Figure 1 As shown, the present invention provides a constant temperature optical fiber coupling table alignment device, including: a coupling table, a position detection system, an automatic control system, an optical power meter and a constant temperature module. Through the coordinated control of optics and mechanics, high-precision coupling alignment of optical devices and optical fibers is achieved to ensure efficient transmission of light energy.

[0049] The coupling platform includes: a four-axis stage and a fiber clamping member arranged on the coupling platform; an optical device 1 to be coupled into the optical fiber is arranged on the four-axis stage, and the four-axis stage is an X / Y / Z three-axis translation stage (resolution ≤ 0.1 μm) driven by a high-precision linear motor, and a rotation axis (θ axis, resolution ≤ 0.01°) for adjusting the spatial posture of the optical device 1; the fiber clamping member is used to fix the head end of the optical fiber 8 to be coupled, specifically, an elastic clamp is used to fix the optical fiber 8 to be coupled, and the end face of the optical fiber 8 to be coupled coincides with the focal plane of the first lens 4.

[0050] Furthermore, the four-axis stage base and the coupling stage body are fixed by a low thermal expansion coefficient material (such as Invar) to reduce the influence of temperature deformation.

[0051] The coupling platform also includes: an alignment optical path arranged between the optical device 1 and the optical fiber 8 to be coupled, and an auxiliary optical path arranged perpendicular to the alignment optical path; the alignment optical path includes: a collimator 2, a beam splitter 3 and a first lens 4 arranged in sequence on the optical axis of the optical device 1. The numerical aperture (NA) of the collimator 2 matches the NA of the optical device 1, and the focal length f 1 For example, 1 =5mm, it is suitable for semiconductor lasers. The splitting ratio of the beam splitter 3 can be selected as 50:50 or 80:20, the reflected light is used for the auxiliary light path, the transmitted light is used for the main coupling stage, and the coating wavelength matches the working band (such as 1550nm). The focal length of the first lens 4 is f 2 , satisfying f 2 >f 1 , so that the collimated beam is focused onto the fiber end face (when the fiber core diameter d = 9 μm, f 2 =10mm, NA=0.15).

[0052] The auxiliary optical path includes: a second lens 5 and a target 6 arranged on the reflected optical path of the beam splitter 3. The focal length f of the second lens 5 is 3 , which matches the distance from the beam splitter 3 to the target 6, so that the reflected light is focused on the surface of the target 6.

[0053] The optical path layout in this embodiment is specifically as follows:

[0054] Main optical path: optical device 1 → collimator 2 → beam splitter 3 → first lens 4 → optical fiber end face;

[0055] Auxiliary optical path: light reflected by beam splitter 3 → second lens 5 → surface of target 6;

[0056] The two optical paths are strictly perpendicular to ensure that the light spot position of the target 6 is in a linear mapping relationship with the position of the optical fiber end face.

[0057] The target 6 is made of black anodized aluminum (surface reflectivity <2%) with a flatness of λ / 10 (λ

[0058] =632.8nm), the center of the target 6 is a cross line with a line width of 10μm, which serves as the origin of the coordinate system.

[0059] The position detection system is used to detect the coordinates of the light spot on the surface of the target 6; the position detection system includes: an industrial camera 7 and a light spot centroid position calculation module; the industrial camera 7 captures the light spot position located on the surface of the target 6.

[0060] Industrial camera configuration: global shutter CMOS (resolution 2048×2048, pixel size 3.45μm), with telecentric lens (magnification 0.5x, working distance 100mm), imaging calibration by calibrating the camera intrinsic parameters (distortion <0.1%) and extrinsic parameters (optical axis is perpendicular to the target surface) through checkerboard calibration.

[0061] The light spot centroid position calculation module includes: a centroid determination unit, which calculates the light spot centroid through edge detection based on the light spot position on the surface of the target 6; a centroid position calculation unit, which establishes a cross coordinate axis based on the target 6 reference, and determines the coordinate information of the light spot centroid according to the light spot centroid calculated by the centroid determination unit.

[0062] It is worth noting that the method for calculating the centroid position of the light spot includes the following steps:

[0063] 1) Extracting the spot area from the original spot image on the surface of the target 6; performing Gaussian filtering denoising and adaptive threshold segmentation on the spot area in order to eliminate background noise interference.

[0064] 2) Determine the spot shape through edge detection, specifically: first use canny edge detection to locate the edge contour of the spot, and select the largest connected area, i.e. the main spot. Canny edge detection parameter setting: low threshold T low : Take 0.5 times the Otsu threshold; high threshold T high : Take 1.5 times the Otsu threshold.

[0065] 3) Calculate the centroid of the light spot and its coordinate information according to the light spot shape, specifically: extract all non-zero pixel coordinates in the light spot shape according to the binary image mask, and calculate its geometric center position (centroid):

[0066]

[0067] Among them, (x i ,y i ) is the pixel coordinate within the spot area, and n is the total number of pixels within the spot area.

[0068] Using a standard calibration plate (such as a chessboard), knowing the actual size L of each square, calculate the pixel ratio k:

[0069] Assume that the origin of the target 6 coordinate system is the center of the cross mark (x 0 ,y 0 ), the actual coordinates are:

[0070] X real =(x c -x 0 )·k,Y real =(yc -y 0 )·k.

[0071] The automatic control system controls the four-axis stage to adjust the position and angle of the optical device 1 according to the light spot coordinates output by the position detection system, so that the light of the optical device 1 is vertically incident on the coupling end face of the optical fiber 8 to be coupled through the first lens 4.

[0072] The automatic control system includes:

[0073] The adjustment path analysis module analyzes the optimal adjustment path from the current light spot coordinates to the target coordinates according to the light spot coordinates on the auxiliary light path output by the position detection system;

[0074] The automatic control module controls the four-axis stage to adjust the position and angle of the optical device 1 according to the optimal adjustment path output by the adjustment path analysis module, so that the light of the optical device 1 passes through the first lens 4 and vertically enters the coupling end face of the optical fiber 8 to be coupled.

[0075] The other end of the optical fiber 8 to be coupled is connected to an optical power meter, and the input end of the optical power meter is connected to the output end of the optical fiber 8 to be coupled, so that the energy of the light incident into the detection device can be detected in real time, and when the light energy does not meet the use requirements, the information is transmitted to the controller, and the controller adjusts the light emission angle and position of the optical device 1. If the energy detection standard is still not met after a certain number of tests, the detection of the optical device 1 is stopped and it is identified as a defective product.

[0076] The present invention provides a constant temperature optical fiber coupling stage alignment device and a method for using the same. By using an alignment optical path in conjunction with an auxiliary optical path, and using an industrial camera 7 to obtain the position of a light spot emitted by the auxiliary optical path to the surface of a target 6, and then calculating the optimal adjustment path from the light spot coordinate to the reference point, the four-axis stage is controlled to adjust the position and angle of the optical device 1, so that the light of the optical device 1 is vertically incident on the coupling end face of the optical fiber 8 to be coupled through the first lens 4. Compared with the prior art, the present invention reduces the difficulty of monitoring the position of the light at the optical fiber coupling end face, and can realize automatic adjustment, so that the light can be vertically incident on the optical fiber coupling end face, ensuring that the light loss coupled into the optical fiber is minimal and the efficiency is high.

[0077] Constant temperature module, the constant temperature module is used to control the temperature of the coupling platform within a set range.

[0078] like Figure 2 As shown, the present invention also provides a method for using a constant temperature optical fiber coupling stage alignment device, comprising the following steps:

[0079] S1. Set a reference point at the center of the surface of the target 6 and establish a rectangular coordinate system. The reference point is the origin of the coordinate system and corresponds to the coupling end surface of the optical fiber 8 to be coupled;

[0080] S2, the light emitted by the optical device 1 is collimated by the collimator 2, and then divided into the transmitted light and the reflected light by the beam splitter 3. The reflected light will be reflected to the second lens 5, and the focus of the second lens 5 is concentrated on the surface of the target 6;

[0081] S3, photographing the surface image of the target 6 by the industrial camera 7 to obtain the light spot coordinates;

[0082] S4. Calculate the optimal adjustment path from the light spot coordinates to the reference point to control the four-axis stage to adjust the position and angle of the optical device 1 so that the light of the optical device 1 passes through the first lens 4 and vertically enters the coupling end face of the optical fiber 8 to be coupled.

[0083] Furthermore, the calculation of the light spot coordinates includes the following steps:

[0084] S31, preprocessing the image captured by the industrial camera 7;

[0085] S32, using an edge detection algorithm to extract the light spot boundary and separate the light spot area from the background;

[0086] S33, by traversing all the pixel points belonging to the light spot in the image, calculating the average value of the coordinates of these pixel points, and obtaining the centroid position of the light spot.

[0087] The present invention, through the setting of the target 6, makes the light passing through the beam splitter 3 incident on the surface of the target 6. The target 6 is non-reflective and has extremely high flatness. The position of the light spot on the surface of the target 6 can be clearly obtained by the industrial camera 7, and the centroid position of the light spot can be obtained by edge detection and calculation, thereby improving the accuracy of the light spot position. Compared with the prior art, the light spot obtained by the industrial camera 7 is a circular area. The present invention further determines the light spot position at a point, thereby improving the accuracy of the coupling alignment.

[0088] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A constant temperature optical fiber coupling stage alignment device, characterized in that: include: Coupling station, A four-axis stage and an optical fiber clamping member disposed on the coupling platform; An optical device to be coupled into the optical fiber is arranged on the four-axis stage; The optical fiber clamp is used to fix the head end of the optical fiber to be coupled; The coupling platform further comprises: an alignment optical path arranged between the optical device and the optical fiber to be coupled, and an auxiliary optical path arranged perpendicular to the alignment optical path; the alignment optical path comprises: a collimator, a beam splitter and a first lens arranged in sequence on the optical axis of the optical device; the auxiliary optical path comprises: a second lens and a target arranged on the reflection optical path of the beam splitter; Also included is a position detection system for detecting the coordinates of the light spot on the surface of the target; It also includes an automatic control system, which controls the four-axis stage to adjust the position and angle of the optical device according to the light spot coordinates output by the position detection system, so that the light of the optical device is vertically incident on the coupling end face of the optical fiber to be coupled through the first lens; An optical power meter is also included, and the other end of the optical fiber to be coupled is connected to the optical power meter.

2. A constant temperature optical fiber coupling stage alignment device according to claim 1, characterized in that: The first lens is arranged on the projection light path of the beam splitter, and the coupling section of the optical fiber to be coupled is arranged on the focus of the first lens.

3. The constant temperature optical fiber coupling stage alignment device according to claim 1, characterized in that: The focal point of the second lens is on the target surface.

4. The constant temperature optical fiber coupling stage alignment device according to claim 1, characterized in that: A cross reference mark is arranged at the center of the target.

5. The constant temperature optical fiber coupling stage alignment device according to claim 1, characterized in that: The position detection system comprises: an industrial camera and a light spot centroid position calculation module; The industrial camera captures the position of the light spot on the surface of the target; The light spot centroid position calculation module includes: A centroid determination unit, which calculates the centroid of the light spot by edge detection based on the position of the light spot on the target surface; A centroid position calculation unit; establishes a cross coordinate axis according to the target reference, and determines the coordinate information of the light spot centroid according to the light spot centroid calculated by the centroid determination unit.

6. The constant temperature optical fiber coupling stage alignment device according to claim 1, characterized in that: The automatic control system comprises: An adjustment path analysis module is configured to analyze an optimal adjustment path from the current light spot coordinates to the target coordinates according to the light spot coordinates on the auxiliary light path output by the position detection system; The automatic control module controls the four-axis stage to adjust the position and angle of the optical device according to the optimal adjustment path output by the adjustment path analysis module, so that the light of the optical device is vertically incident on the coupling end face of the optical fiber to be coupled through the first lens.

7. The constant temperature optical fiber coupling stage alignment device according to claim 1, characterized in that: It also includes a constant temperature module, which is used to control the temperature of the coupling platform within a set range.

8. A method for using a constant temperature optical fiber coupling stage alignment device, based on the constant temperature optical fiber coupling stage alignment device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Setting a reference point at the center of the target surface and establishing a rectangular coordinate system, wherein the reference point is the origin of the coordinate system and corresponds to the coupling end surface of the optical fiber to be coupled; S2. The light emitted by the optical device is collimated by the collimator and then divided into transmitted light and reflected light by the beam splitter. The reflected light will be reflected to the second lens, and the focus of the second lens is concentrated on the surface of the target; S3, taking a target surface image through an industrial camera to obtain the light spot coordinates; S4. Calculate the optimal adjustment path from the light spot coordinates to the reference point to control the four-axis stage to adjust the position and angle of the optical device so that the light of the optical device passes through the first lens and vertically enters the coupling end face of the optical fiber to be coupled.

9. The method for using the constant temperature optical fiber coupling stage alignment device according to claim 8, characterized in that: The calculation of the light spot coordinates includes the following steps: S31, preprocessing the image captured by the industrial camera; S32, using an edge detection algorithm to extract the light spot boundary and separate the light spot area from the background; S33, by traversing all the pixel points belonging to the light spot in the image, calculating the average value of the coordinates of these pixel points, and obtaining the centroid position of the light spot.

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