WO2024094230A1

WO2024094230A1 - Measurement device and measurement method for transmittance and numerical aperture of optical fiber

Info

Publication number: WO2024094230A1
Application number: PCT/CN2023/143310
Authority: WO
Inventors: 贺谭斌; 范建华; 徐宁; 董李昌; 吴兆豪; 张武海; 曾成; 张晶
Original assignee: 长园视觉科技(珠海)有限公司
Priority date: 2022-11-03
Filing date: 2023-12-29
Publication date: 2024-05-10
Also published as: CN115839826B; CN115839826A

Abstract

Disclosed in the present application are a measurement device and measurement method for the transmittance and numerical aperture of an optical fiber. The measurement device comprises a laser source, a first optical fiber holder, a first lens set, a second optical fiber holder, a second lens set, an optical power meter and an imaging camera, wherein the laser source outputs a test beam through an exit optical fiber; the first optical fiber holder is used for fixing an output end of the exit optical fiber; the distance between the first lens set and the first optical fiber holder is adjustable, and the first lens set is used for shaping the test beam output through the exit optical fiber; the second optical fiber holder is used for fixing an optical fiber to be tested; the second lens set is used for shaping the test beam output through the optical fiber to be tested; the optical power meter is used for acquiring the transmittance of the optical fiber to be tested through which the test beam passes; and the imaging camera is used for testing topography data of a light spot. By adjusting the distance between the first lens set and the first optical fiber holder, the transmittance and numerical aperture of a product can be tested simultaneously.

Description

Device and method for detecting transmittance and numerical aperture of optical fiber

Technical Field

The present application relates to the technical field of optical device performance detection, and in particular to a detection device and a detection method for optical fiber transmittance and numerical aperture.

Background technique

With the rapid development of optical communication technology, the application of optical fiber, or optical fiber, has become very popular. In optics, the numerical aperture of an optical fiber describes the cone angle when light enters and exits the optical fiber, indicating the ability of the optical fiber to receive incident light. In the optical fiber communication system, there are certain requirements for the numerical aperture of the optical fiber. Usually, in order to most effectively inject light into the optical fiber, a lens with the same numerical aperture as the optical fiber numerical aperture should be used to collect light. The transmittance is a direct representation of the optical device's ability to transmit light. Therefore, accurately measuring the numerical aperture and transmittance is very meaningful for measuring the quality of optical fiber products. In current products, the test system cannot complete the test of the numerical aperture and transmittance of optical fiber products at the same time, and there are multiple problems such as low test repeatability, complex debugging, and easy damage to materials.

Summary of the invention

In order to solve at least one of the above technical problems, the present application provides a detection device and a detection method for optical fiber transmittance and numerical aperture, and the technical solution adopted is as follows:

The detection device for the transmittance and numerical aperture of an optical fiber provided in the present application comprises a laser light source, a first optical fiber fixing frame, a first lens group, a second optical fiber fixing frame, a second lens group, an optical power meter, and an imaging camera. The laser light source outputs a test beam through an output optical fiber; the first optical fiber fixing frame is used to fix the output end of the output optical fiber; the distance between the first lens group and the first optical fiber fixing frame is adjustable, and the first lens group is used to shape the test beam output by the output optical fiber; the second optical fiber fixing frame is used to fix the optical fiber to be tested; the second lens group is used to shape the test beam output by the optical fiber to be tested; the optical power meter is used to obtain the transmittance of the test beam passing through the optical fiber to be tested; and the imaging camera is used to test the light spot morphology data.

In certain embodiments of the present application, the first lens group includes two convex lenses, the convex surfaces of the two convex lenses are arranged opposite to each other, and the distance from the output end of the output optical fiber to the first lens group is adjusted to adjust the numerical aperture of the light source incident on the optical fiber to be tested.

In some embodiments of the present application, the second lens group includes an objective lens, a condenser lens group, and a beam splitter prism. The objective lens is arranged behind the second optical fiber fixing frame, and the objective lens shapes the light beam output by the optical fiber to be tested into a parallel light beam; the condenser lens group is arranged behind the objective lens, and the condenser lens group focuses the parallel light beam into an image and outputs it to the imaging camera; The beam splitter prism is arranged between the objective lens and the condenser lens group, and the beam splitter prism splits the test beam into a first beam and a second beam. The first beam is output to the optical power meter, and the second beam is output to the imaging camera via the condenser lens group.

In certain embodiments of the present application, the testing device includes a first mobile platform, a second mobile platform, and a third mobile platform. The laser light source, the first optical fiber fixing frame, and the first lens group are installed on the first mobile platform, the second optical fiber fixing frame is installed on the second mobile platform, the second lens group, the optical power meter, and the imaging camera are installed on the third mobile platform, the first mobile platform and the second mobile platform are both configured as five-axis adjustable platforms, and the distance between the third mobile platform and the second mobile platform is adjustable.

In certain embodiments of the present application, the detection device includes a fixed platform, and the first mobile platform, the second mobile platform, and the third mobile platform are installed on the fixed platform. The fixed platform is equipped with rubber damping vibration isolation pads and a horizontal bearing adjustment mechanism. The horizontal bearing adjustment mechanism is used to adjust the level of the fixed platform to ensure the accuracy of the test results, and the rubber damping vibration isolation pads are used to enhance the seismic resistance of the fixed platform.

In certain embodiments of the present application, the detection device includes a control system, the control system includes an axis adjustment feedback unit, and the axis adjustment feedback unit is electrically connected to the first mobile platform, the second mobile platform, and the third mobile platform respectively.

In certain embodiments of the present application, the control system includes an image acquisition and computing unit, the image acquisition and computing unit is electrically connected to the imaging camera, and the axis adjustment feedback unit is electrically connected to the image acquisition and computing unit.

In certain embodiments of the present application, the control system is electrically connected to the laser light source, and the laser light source may be an adjustable narrow-band laser light source or a broadband laser light source.

The present application also provides a method for detecting the transmittance and numerical aperture of an optical fiber. The method is implemented based on the aforementioned detection device and includes:

Adjust the position and angle of the laser light source according to the light spot of the imaging camera so that the laser light source and the imaging camera are on the same optical axis;

Place the optical fiber to be tested into the second optical fiber fixing frame, and adjust the second optical fiber fixing frame so that the laser light source, the optical fiber to be tested, and the imaging camera are on the same optical axis;

The distance between the first lens group and the first optical fiber fixing frame is adjusted so that the test light beam is incident on the optical fiber to be tested with different numerical apertures, and the numerical aperture of the optical fiber to be tested is calculated through the light spot obtained by the imaging camera.

In certain embodiments of the present application, when adjusting the second optical fiber fixing bracket, the front end face and the rear end face of the optical fiber to be tested are imaged respectively and the coordinates of the centroid position of the light spot are recorded. When the coordinates of the centroid position of the light spot are consistent twice, the coaxial debugging of the laser light source, the optical fiber to be tested, and the imaging camera is considered to be completed.

The embodiments of the present application have at least the following beneficial effects: the detection device sets a first lens group between the output optical fiber and the optical fiber to be tested to prevent the material from being damaged, and the distance between the first lens group and the output optical fiber is adjusted to make the test beam By entering the optical fiber under test at different incident cone angles, the transmittance can be tested while the numerical aperture of the optical fiber under test can be calculated by measuring the light spot morphology data output by the optical fiber under test with the help of an imaging camera.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

FIG. 1 is a schematic diagram of the structure of a device for detecting the transmittance and numerical aperture of an optical fiber imaging element.

Figure numerals: 110, laser light source; 120, first optical fiber fixing bracket; 121, output optical fiber; 201, first convex lens; 202, second convex lens; 300, second optical fiber fixing bracket; 410, objective lens; 420, beam splitter prism; 430, condenser lens group; 510, optical power meter; 520, imaging camera; 610, first mobile platform; 620, second mobile platform; 630, third mobile platform; 700, control system; 800, fixed platform.

Detailed ways

The embodiments of the present application are described in detail below in conjunction with FIG1 , and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

In the description of the present application, it should be understood that if the terms "center", "middle", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like are used to indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, it is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply 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 a limitation on the present application. The features defined as "first" and "second" are used to distinguish the feature names, rather than having special meanings. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "multiple" means two or more.

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 a direct connection, or it can be indirectly connected through an intermediate medium, or 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 according to specific circumstances.

With the rapid development of optical communication technology, the application of optical fiber has become very popular. In optics, the numerical aperture of an optical fiber describes the cone angle when light enters and exits the optical fiber, indicating the ability of the optical fiber to receive incident light. In optical fiber communication systems, There are certain requirements for the numerical aperture of optical fiber. Usually, in order to most effectively inject light into the optical fiber, a lens with the same numerical aperture as the optical fiber should be used to collect light. Transmittance is a direct representation of the optical device's ability to transmit light. Therefore, accurately measuring the numerical aperture and transmittance is very meaningful for measuring the quality of optical fiber products. In current products, the test system cannot complete the test of the numerical aperture and transmittance of optical fiber products at the same time, and there are multiple problems such as low test repeatability, complex debugging, and easy damage to materials.

The present application relates to a detection device for the transmittance and numerical aperture of an optical fiber. The detection device includes a laser light source 110, a first optical fiber fixing frame 120, a first lens group, a second optical fiber fixing frame 300, a second lens group, an optical power meter 510, and an imaging camera 520. The laser light source 110 outputs a test beam through an output optical fiber 121; the first optical fiber fixing frame 120 is used to fix the output end of the output optical fiber 121; the distance between the first lens group and the first optical fiber fixing frame 120 is adjustable, and the first lens group is used to shape the test beam output by the output optical fiber 121; the second optical fiber fixing frame 300 is used to fix the optical fiber to be tested; the second lens group is used to shape the test beam output by the optical fiber to be tested; the optical power meter 510 is used to obtain the transmittance of the test beam passing through the optical fiber to be tested; and the imaging camera 520 is used to test the light spot morphology data. The detection device sets a first lens group between the output optical fiber 121 and the optical fiber to be tested to avoid material damage. By adjusting the distance between the first lens group and the output optical fiber 121, the test light beam enters the optical fiber to be tested with different incident cone angles. While testing the transmittance, the imaging camera 520 can be used to test the spot morphology data output by the optical fiber to be tested to calculate the numerical aperture of the optical fiber to be tested.

It can be understood that by adjusting the distance between the first optical fiber fixing frame 120 and the first lens group, the test light beam can be incident on the first lens group at different cone angles, and then refracted twice by the first lens group, the cone angle of the light beam emitted from the first lens group is changed, and the divergence degree of the light beam is changed to achieve light beam shaping, so that the light beam is incident on the optical fiber to be tested with different numerical apertures.

Further, the second lens group includes an objective lens 410, a condenser lens group 430, and a beam splitter 420. The objective lens 410 is arranged behind the second optical fiber fixing frame 300, and the objective lens 410 shapes the light beam output by the optical fiber to be tested into a parallel light beam; the condenser lens group 430 is arranged behind the objective lens 410, and the condenser lens group 430 focuses the parallel light beam into an image and outputs it to the imaging camera 520; the beam splitter 420 is arranged between the objective lens 410 and the condenser lens group 430, and the beam splitter 420 splits the test light beam into a first light beam and a second light beam, the first light beam is output to the optical power meter 510, and the second light beam is output to the imaging camera 520 via the condenser lens group 430. It can be understood that in the second lens group, objective lenses 410 with different magnifications can be selected according to the light spot requirements of the product, and the condenser lens group 430 and the objective lenses 410 with different magnifications are combined into an image of a specified method magnification, and the morphological data of the test light spot at the light spot to the imaging camera 520 are output, so as to be suitable for the testing of optical fiber products of multiple specifications. In this embodiment, the first light beam and the second light beam are perpendicular to each other.

Further, the test device includes a first mobile platform 610, a second mobile platform 620, and a third mobile platform 630. The laser light source 110, the first optical fiber fixing frame 120, and the first lens group are installed on the first mobile platform 610. The second optical fiber fixing frame 300 is installed on the second mobile platform 620. The second lens group, the optical power meter 510, and the imaging camera 520 are installed on the third mobile platform 630. The distance between the third mobile platform 630 and the second mobile platform 620 is adjustable. It can be understood that the distance between the first mobile platform 610 and the second mobile platform 620 is adjusted so that the test beam is incident on the optical fiber to be tested with different numerical apertures. The distance between the second movable platform 620 and the third movable platform 630 is adjusted so that the test light beam emitted from the optical fiber to be tested is adjusted to different positions for spot testing.

Specifically, in this embodiment, the first mobile platform 610 and the second mobile platform 620 are both configured as five-axis adjustable platforms, so that the laser light source 110, the first lens group, the optical fiber to be tested and other components can adjust their angles while adjusting their positions, so as to complete coaxial debugging or other product testing and meet the needs of different application scenarios.

It can be understood that the detection device includes a control system 700, and the control system 700 includes an axis adjustment feedback unit, which is electrically connected to the first mobile platform 610, the second mobile platform 620, and the third mobile platform 630. Specifically, the axis adjustment feedback unit includes a PLC and three servo motors corresponding to the first mobile platform 610, the second mobile platform 620, and the third mobile platform 630. The PLC sends corresponding instructions to the specified servo motor to drive the corresponding mobile platform to move, so as to complete the position adjustment.

Furthermore, the control system 700 includes an image acquisition and calculation unit, which is electrically connected to the imaging camera 520, and the axis adjustment feedback unit is electrically connected to the image acquisition and calculation unit. It can be understood that the image acquisition and calculation unit is used to analyze the spot morphology data obtained by the imaging camera 520 test. Specifically, in this embodiment, the image acquisition and calculation unit processes the spot image through a visual algorithm to obtain the product coordinates, and according to the coordinate difference of the center of mass of the spot formed by the front end face imaging and the rear end face of the optical fiber to be tested, the coordinate deviation is fed back to the PLC for processing, and then the PLC sends an instruction to drive the motor to move to the corresponding position to complete the test.

Furthermore, the control system 700 is electrically connected to the laser light source 110, and the laser light source 110 can be an adjustable narrowband laser light source or a broadband laser light source. Compared with the single input light source in the prior art, the present application can adjust the laser light source 110 through the control system 700 to meet various test requirements.

Furthermore, the first lens group includes two convex lenses, and the convex surfaces of the two convex lenses are arranged opposite to each other. The distance from the output end of the output optical fiber 121 to the first lens group is adjusted to adjust the numerical aperture of the light source incident on the optical fiber to be tested. In this embodiment, the first convex lens 201 and the second convex lens 202 are set as single-sided convex lenses. It can be understood that by adjusting the distance between the output optical fiber 121 and the first lens group, the test light beam is incident on the first convex lens 201 at different incident angles, and the light beam is shaped and its divergence angle is changed. Then, it is incident on the second convex lens 202 for focusing, and finally the purpose of adjusting the numerical aperture of the test light beam incident on the optical fiber to be tested is achieved. In other embodiments, considering different beam shaping requirements, the first lens group can also add cylindrical mirrors or other lenses to further shape the test light beam emitted from the output optical fiber.

Further, the testing device includes a fixed platform 800, and the first mobile platform 610, the second mobile platform 620, and the third mobile platform 630 are installed on the fixed platform 800. Specifically, the fixed platform 800 is installed with a rubber damping vibration isolation pad, which is used to enhance the seismic resistance of the fixed platform 800.

Furthermore, the fixed platform 800 is equipped with a horizontal bearing adjustment mechanism. It can be understood that the horizontal bearing adjustment mechanism is used to adjust the level of the fixed platform 800 to ensure the accuracy of the test results. The common optical platform equipment in this field will not be described in detail here.

In some embodiments, the detection device includes a black box, and it can be understood that the black box is used to prevent the influence of the ambient light source on the detection device. Specifically, the black box can cover the fixed platform 800 to protect the entire detection device from the influence of the ambient light source; the black box can also cover the part from the laser light source 110 to the second optical fiber fixing frame 300, that is, the part of the first mobile platform 610 and the second mobile platform 620.

The present application also relates to a method for detecting the transmittance and numerical aperture of an optical fiber. Based on the aforementioned detection device, the detection method includes:

Adjust the position and angle of the laser light source 110 according to the light spot of the imaging camera 520 so that the laser light source 110 and the imaging camera 520 are on the same optical axis;

Place the optical fiber to be tested into the second optical fiber fixing frame 300, and adjust the second optical fiber fixing frame 300 so that the laser light source 110, the optical fiber to be tested, and the imaging camera 520 are on the same optical axis;

The distance between the first lens group and the first optical fiber fixing frame 120 is adjusted so that the test light beam is incident on the optical fiber to be tested with different numerical apertures, and the numerical aperture of the optical fiber to be tested is calculated through the light spot obtained by the imaging camera 520.

Specifically, taking the light spots a and b obtained by the imaging camera 520 when the first lens group is in different positions as an example, the method for calculating the numerical aperture through the light spot formed by the optical fiber to be tested includes:

Assume that the centroid abscissa of spot a is _Xa mm, the diameter of spot a is _Da mm, the centroid abscissa of spot b is _Xb mm, the diameter of spot b is _Db mm, and the numerical aperture of the optical fiber to be tested is calculated as NA = sin(atan(( _Db - _Da )/2)/( _Xb - _Xa )).

Furthermore, when adjusting the second optical fiber fixing bracket 300, the front end face and the rear end face of the optical fiber to be tested are imaged respectively and the coordinates of the centroid position of the light spot are recorded. When the coordinates of the centroid position of the two light spots are consistent, the coaxial debugging of the laser light source 110, the optical fiber to be tested and the imaging camera 520 is considered to be completed.

Specifically, taking a coaxial debugging process as an example, assuming that the centroid of the light spot imaged by the front end face of the optical fiber to be tested is the center of the field of view, and the centroid of the light spot imaged by the rear end face of the optical fiber to be tested has an X-axis deviation A ₁ and a Y-axis deviation B ₁ , the axis adjustment feedback unit drives the second mobile platform 620 to move the centroid of the light spot along the X-axis toward the center, and the movement amount A ₂ is A ₁ /2, and the adjustment is repeated until the centroid of the light spot coincides with the center of the field of view, and then the second mobile platform 620 is driven to move the centroid of the light spot along the Y-axis toward the center, and the movement amount B ₂ is B ₁ /2. Repeated adjustment until the centroid of the light spot coincides with the center of the field of view is considered to be completed.

In the description of this specification, if the reference terms "one embodiment", "some examples", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

The above describes the implementation methods of the present application in detail in conjunction with the accompanying drawings, but the present application is not limited to the above implementation methods. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of this application.

Claims

The detection device for optical fiber transmittance and numerical aperture includes:

A laser light source (110), wherein the laser light source (110) outputs a test light beam through an output optical fiber (121);

A first optical fiber fixing frame (120), the first optical fiber fixing frame (120) being used to fix the output end of the output optical fiber (121);

a first lens group, wherein the distance between the first lens group and the first optical fiber fixing frame (120) is adjustable, and the first lens group is used for shaping the test light beam output by the output optical fiber (121);

A second optical fiber fixing frame (300), the second optical fiber fixing frame (300) being used to fix the optical fiber to be tested;

A second lens group, wherein the second lens group is used to shape a test light beam output by the optical fiber to be tested;

An optical power meter (510), the optical power meter (510) being used to obtain the transmittance of a test light beam passing through the optical fiber to be tested;

An imaging camera (520), wherein the imaging camera (520) is used to test light spot shape data.
According to claim 1, the detection device for optical fiber transmittance and numerical aperture, wherein: the first lens group includes two convex lenses, the convex surfaces of the two convex lenses are arranged opposite to each other, and the distance from the output end of the output optical fiber (121) to the first lens group is adjusted to adjust the numerical aperture of the light source incident on the optical fiber to be tested.
The device for detecting transmittance and numerical aperture of an optical fiber according to claim 1, wherein the second lens group comprises:

an objective lens (410), the objective lens (410) being arranged behind the second optical fiber fixing frame (300), and the objective lens (410) shaping the light beam output by the optical fiber to be tested into a parallel light beam;

A condenser lens group (430), the condenser lens group (430) being arranged behind the objective lens (410), the condenser lens group (430) focusing the parallel light beam into an image and outputting the image to the imaging camera (520);

A beam splitter prism (420) is arranged between the objective lens (410) and the condenser lens group (430), and the beam splitter prism (420) splits the test light beam into a first light beam and a second light beam, wherein the first light beam is output to the optical power meter (510), and the second light beam is output to the imaging camera (520) via the condenser lens group (430).
According to claim 1, the detection device for optical fiber transmittance and numerical aperture, wherein: the testing device comprises a first mobile platform (610), a second mobile platform (620), and a third mobile platform (630); the laser light source (110), the first optical fiber fixing frame (120), and the first lens group are installed on the first mobile platform (610); the second optical fiber fixing frame (300) is installed on the second mobile platform (620); the second lens group, the optical power meter (510), and the imaging camera (520) are installed on the third mobile platform (630); the first mobile platform (610) and the second mobile platform (620) are both configured as five-axis adjustable platforms; and the distance between the third mobile platform (630) and the second mobile platform (620) is adjustable.
The detection device for optical fiber transmittance and numerical aperture according to claim 4, wherein: The invention comprises a fixed platform (800), wherein the first mobile platform (610), the second mobile platform (620), and the third mobile platform (630) are installed on the fixed platform (800), and the fixed platform (800) is provided with a rubber damping vibration isolation pad and a horizontal bearing adjustment mechanism, wherein the horizontal bearing adjustment mechanism is used to adjust the level of the fixed platform (800) to ensure the accuracy of the test result, and the rubber damping vibration isolation pad is used to enhance the seismic resistance of the fixed platform (800).
According to claim 4, the detection device for optical fiber transmittance and numerical aperture, wherein: the detection device includes a control system (700), the control system (700) includes an axis adjustment feedback unit, and the axis adjustment feedback unit is electrically connected to the first movable platform (610), the second movable platform (620), and the third movable platform (630), respectively.
According to claim 6, the detection device for optical fiber transmittance and numerical aperture, wherein: the control system (700) includes an image acquisition and calculation unit, the image acquisition and calculation unit is electrically connected to the imaging camera (520), and the axis adjustment feedback unit is electrically connected to the image acquisition and calculation unit.
According to the detection device for optical fiber transmittance and numerical aperture as described in claim 7, wherein: the control system (700) is electrically connected to the laser light source (110), and the laser light source (110) can be an adjustable narrow-band laser light source or a broadband laser light source.
A method for detecting transmittance and numerical aperture of an optical fiber, implemented based on the detection device according to any one of claims 1 to 8, wherein:

Adjust the position and angle of the laser light source according to the light spot of the imaging camera so that the laser light source and the imaging camera are on the same optical axis;

Place the optical fiber to be tested into the second optical fiber fixing frame, and adjust the second optical fiber fixing frame so that the laser light source, the optical fiber to be tested, and the imaging camera are on the same optical axis;

The distance between the first lens group and the first optical fiber fixing frame is adjusted so that the test light beam is incident on the optical fiber to be tested with different numerical apertures, and the numerical aperture of the optical fiber to be tested is calculated through the light spot obtained by the imaging camera.
According to the detection method for optical fiber transmittance and numerical aperture of claim 9, wherein: when adjusting the second optical fiber fixing frame, the front end face and the rear end face of the optical fiber to be tested are imaged respectively and the coordinates of the centroid position of the light spot are recorded, and when the coordinates of the centroid position of the light spot are consistent twice, it is considered that the coaxial debugging of the laser light source, the optical fiber to be tested, and the imaging camera is completed.