A device and method for measuring off-axisness and divergence of a lensed fiber output beam

Abstract

The present application relates to the technical field of optical fiber testing, and particularly relates to a device and method for measuring the off-axis degree and divergence angle of a lens optical fiber, comprising an optical fiber clamping and fine adjustment module for clamping and fine adjustment of the optical fiber; an optical testing module for detecting the light beam of the lens optical fiber; and a visual monitoring module for monitoring the position of the side surface of the optical fiber in two axial directions and spatially positioning the end surface of the optical fiber. The present application is based on a beam quality analyzer to develop the testing device and method, which can measure the off-axis degree and divergence angle of the light beam of the lens optical fiber at the same time, thereby effectively solving the problems of how to measure and simultaneously measure the off-axis degree and divergence angle, and achieving the measurement of a large number of products with high measurement efficiency, and meeting the requirements of modern optical fiber testing technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical fiber testing, in particular to a device and method for measuring the off-axis degree and divergence angle of a lens optical fiber. BACKGROUND

[0002] Lens optical fiber is a kind of optical passive device. It can be directly coupled with a semiconductor laser chip due to its special lens structure on the end face. The cylindrical or spherical lens structure on the end face is processed by grinding, polishing or electric discharge arc melting. This structure can couple the nearly elliptical or circular spot emitted by the semiconductor laser chip into the fiber core with high coupling efficiency.

[0003] During the process of lens processing on the end face of the optical fiber, the end face of the wedge-shaped lens optical fiber may be asymmetrically ground, and the end face of the tapered lens optical fiber may be eccentrically ground. In terms of geometric structure, the cylindrical axis of the end face of the wedge-shaped lens optical fiber does not intersect with the core axis, and the center of the sphere of the end face of the tapered lens optical fiber is not on the core axis. This will cause the center axis of the light spot emitted from the end face of the lens optical fiber to deviate from the center axis of the optical fiber, and the deviation angle between the two axes can be called off-axis degree.

[0004] The off-axis degree is mainly used to evaluate the processing quality of the lens optical fiber. Since the optical path is reversible, when coupling, the light axis of the semiconductor laser chip needs to be adjusted to coincide with the light axis of the end face of the lens optical fiber to achieve the highest coupling efficiency. Since the direct object of coupling adjustment is the optical fiber, if there is a large off-axis degree between the light axis of the end face of the lens optical fiber and the core axis of the optical fiber, it will bring great difficulty to the coupling work and directly affect the maximum coupling efficiency.

[0005] When processing the lens on the end face of the optical fiber, the curvature radius of the cylindrical or spherical lens structure on the end face can directly reflect the divergence degree of the light beam emitted from the lens optical fiber. The divergence angle of the lens optical fiber is usually defined based on the half width (FWHM) of light intensity, which corresponds to the divergence angle of the semiconductor laser chip. Since the optical path is reversible, when the divergence angles of the fast and slow axes are consistent, the spot mode matching can be achieved, and high coupling efficiency can be achieved.

[0006] By measuring the off-axis degree and divergence angle of the light axis of the lens optical fiber, the processing quality of the lens optical fiber can be reliably evaluated. In the existing technology, the test equipment or method cannot measure the off-axis degree and divergence angle parameters at the same time, and the test process of a single parameter is complicated and low in efficiency, which is not conducive to the mass measurement of lens optical fiber products. Therefore, we propose a device and method for measuring the off-axis degree and divergence angle of the light beam emitted from the lens optical fiber. SUMMARY

[0007] Based on the technical problems existing in the background art, the present application provides a device and method for measuring the off-axis degree and divergence angle of the light beam of a lens optical fiber, which can measure the divergence angle of the light beam of the lens optical fiber while realizing the detection of the off-axis degree, thereby effectively solving the problems in the prior art that the test equipment or method cannot simultaneously measure the off-axis degree and divergence angle parameters, and the test process of a single parameter is complicated and low in efficiency, which is not conducive to the mass measurement of lens optical fiber products.

[0008] The present application provides the following technical solutions: a device and method for measuring the off-axis degree and divergence angle of the light beam of a lens optical fiber, comprising a fiber clamping and fine adjustment module, an optical test module and a visual monitoring module.

[0009] The fiber clamping and fine adjustment module comprises an adjusting mechanism and a quantization mechanism, the adjusting mechanism is used for clamping the optical fiber and performing fine adjustment, and the quantization mechanism is used for recording the translation amount and rotation angle of the optical fiber.

[0010] One end of the optical fiber with a lens is placed on the clamping jig of the fiber clamping and fine adjustment module, and the other end is connected to a pump light source.

[0011] The optical test module is used for detecting the light beam of the lens optical fiber, and the visual monitoring module is used for monitoring the position of the side surface of the optical fiber in two axial directions and spatially positioning the end surface of the optical fiber.

[0012] Preferably, the fiber clamping and fine adjustment module comprises a five-dimensional sliding table, a moving block, a locking block, a fiber rotation clamp, a connecting seat and a closed loop ceramic sleeve, the moving block is adjustably arranged on the dovetail groove of the five-dimensional sliding table and is fixed by the locking block, the upper end of the moving block is used for fixing the fiber rotation clamp, the connecting seat is fixed with the fiber rotation clamp, and the closed loop ceramic sleeve is fixed in the upper end circular hole of the connecting seat, and the lens optical fiber can be inserted into the closed loop ceramic sleeve for guiding and supporting the lens optical fiber.

[0013] Preferably, the fiber rotation clamp is used for rotating along the fiber axis direction after the locking block locks the optical fiber, and the fiber rotation clamp is provided with an angle scale for quantizing the rotation angle of the optical fiber.

[0014] Preferably, the optical test module comprises a light beam analyzer base and a light beam analyzer, the light beam analyzer base is connected to the bottom plate, and the light beam analyzer is connected to the light beam analyzer base in a horizontal manner through a positioning pin.

[0015] Preferably, the fiber groove and rotation center on the fiber rotation clamp, the center of the closed loop ceramic sleeve and the center of the light beam analyzer sensor are on the same axis and coincide with the fiber axis.

[0016] Preferably, the visual monitoring module comprises a horizontal visual monitoring unit for monitoring and positioning the movement and rotation state of the lens fiber in the vertical direction, and a vertical visual monitoring unit for monitoring and positioning the movement and rotation state of the lens fiber in the horizontal direction.

[0017] Preferably, the horizontal visual monitoring unit comprises a vertical fixing seat, a lens barrel fixing frame I, and a CCD microscope I connected with the vertical fixing seat through the lens barrel fixing frame I.

[0018] The vertical visual monitoring unit comprises a vertical support, a horizontal adjusting plate, a lens barrel fixing frame II, and a CCD microscope II arranged on the horizontal adjusting plate through the lens barrel fixing frame II, and the horizontal adjusting plate is used for adjusting the relative position between the lens barrel fixing frame II and the vertical support.

[0019] A method for measuring the off-axis degree and divergence angle of the light beam of a lens fiber, comprising the following steps:

[0020] S1, placing the lens fiber to be measured on a fiber rotation clamp, so that the fiber end surface passes through a closed-loop ceramic ferrule and exposes a certain length of fiber;

[0021] S2, using a five-dimensional slide to send the end surface of the lens fiber to the test area along the fiber axis direction, and adjusting the end surface of the lens fiber to the position to be measured with the assistance of the horizontal visual monitoring unit and the vertical visual monitoring unit in the visual monitoring module;

[0022] S3, rotating the fiber rotation clamp until the spot on the monitoring interface of the beam analyzer presents the minimum ellipticity value, and the length of the fast axis direction of the spot reaches the maximum value and the length of the slow axis direction reaches the minimum value based on the half-width of the spot intensity, and then adjusting the five-dimensional slide so that the end surface of the lens fiber is simultaneously in the fixed position calibrated by the horizontal visual monitoring unit and the vertical visual monitoring unit in the visual monitoring module, recording the position of the lens fiber at this time as state one, recording the coordinate value of the spot center at state one, recording the size of the spot in the fast axis and slow axis directions, and recording the distance between the end surface of the lens fiber and the detector plane;

[0023] S4, calculating the off-axis degree of the light beam of the lens fiber in the fast axis and slow axis directions by capturing the coordinate value of the spot center, the size of the spot in the fast axis and slow axis directions, and the distance between the end surface of the lens fiber and the detector plane recorded in step S3, and calculating the divergence angle in the fast axis and slow axis directions according to the size of the spot in the fast axis and slow axis directions.

[0024] Preferably, the fiber axis at the fixed position in step S3 is perpendicular to the detector plane and passes through the center of the detector.

[0025] The application provides a device and method for measuring the off-axis degree and divergence angle of a lens fiber light beam.

[0026] The application utilizes the characteristics of the real-time measurement of the energy field intensity distribution of a Gaussian light beam by a beam analyzer, and can measure the divergence angle and off-axis degree of the fast axis and slow axis of the lens fiber at one time. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the application.

[0028] Figure 2 It is a system principle diagram of the application.

[0029] In the figure: 1, base plate; 2, fiber clamping and fine adjustment module; 21, five-dimensional slide table; 22, moving block; 23, locking block; 24, fiber rotating clamp; 25, connecting seat; 26, closed loop ceramic sleeve; 3, optical test module; 31, beam analyzer base; 32, beam analyzer; 4, visual monitoring module; 41, vertical fixed seat; 42, lens barrel fixing frame one; 43, CCD microscope one; 44, vertical support; 45, horizontal adjusting plate; 46, lens barrel fixing frame two; 47, CCD microscope two. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0031] As shown in Figure 1 and 2 , the application provides a technical solution: a device for measuring the off-axis degree and divergence angle of a lens fiber light beam, comprising a base plate 1, a fiber clamping and fine adjustment module 2, an optical test module 3 and a visual monitoring module 4.

[0032] The fiber clamping and fine adjustment module 2 comprises a five-dimensional slide 21, a moving block 22, a locking block 23, a fiber rotating clamp 24, a connecting seat 25, and a closed-loop ceramic sleeve 26. The moving block 22 is located on the dovetail groove of the five-dimensional slide 21, and the upper end of the moving block 22 is used for fixing the fiber rotating clamp 24. The moving block 22 can be adjusted on the dovetail groove and fixed by the locking block 23. The connecting seat 25 is fixed with the fiber rotating clamp 24, and the upper end circular hole of the connecting seat 25 is fixed with the closed-loop ceramic sleeve 26. The lens fiber can be inserted into the closed-loop ceramic sleeve 26 for guiding and supporting. The fiber rotating clamp 24 can be rotated along the fiber axis direction after locking the fiber with the locking block. The fiber rotating clamp 24 is provided with an angle scale for quantifying the rotation angle of the fiber.

[0033] By adjusting the fiber clamping and fine adjustment module 2, the lens fiber is in the test position of the visual monitoring module 4, and the fiber axis is perpendicular to the detector plane and passes through the center of the detector.

[0034] The optical test module 3 comprises a light beam analyzer base 31 and a light beam analyzer 32. The light beam analyzer base 31 is connected to the bottom plate 1, and the light beam analyzer 32 adopts a sensor made of Ge material and works in a slit scanning mode. The light beam analyzer 32 is connected to the light beam analyzer base 31 in a horizontal manner through a positioning pin. Further, the fiber groove and the rotation center of the fiber rotating clamp 24, the center of the closed-loop ceramic sleeve 26, and the center of the sensor of the light beam analyzer 32 are on the same axis and coincide with the fiber axis.

[0035] When the lens fiber is placed on the fiber rotating clamp 24, it can pass through the closed-loop ceramic sleeve 26 and expose an appropriate length of fiber. The five-dimensional slide 21 can adjust the lens fiber to be perpendicular to the sensor plane of the light beam analyzer 32.

[0036] The visual monitoring module 4 comprises a vertical fixing seat 41, a lens barrel fixing frame one 42, a CCD microscope one 43, a vertical support 44, a horizontal adjustment plate 45, a lens barrel fixing frame two 46, and a CCD microscope two 47. It is used for monitoring the movement and rotation state of the lens fiber and positioning it in space. The horizontal visual monitoring unit comprises the vertical fixing seat 41, the lens barrel fixing frame one 42, and the CCD microscope one 43, which can monitor and position the movement and rotation state of the lens fiber in the vertical direction. The vertical visual monitoring unit comprises the vertical support 44, the horizontal adjustment plate 45, the lens barrel fixing frame two 46, and the CCD microscope two 47, which can monitor and position the movement and rotation state of the lens fiber in the horizontal direction.

[0037] The optical test module 3 is connected to a computer and can extract beam measurement data from the light beam analyzer 32 using existing technology. After calculation and analysis, the lens fiber beam off-axis degree and divergence angle data are obtained.

[0038] The application also provides a method for measuring the off-axis degree and divergence angle of the light beam of a lens fiber, which adopts the device for measuring the off-axis degree and divergence angle of the light beam of a lens fiber.

[0039] S1, placing the lens fiber to be measured on the fiber rotating clamp 24, so that the fiber end surface passes through the closed-loop ceramic ferrule and exposes a certain length of fiber;

[0040] S2, using the five-dimensional slide table 21 to send the end surface of the lens fiber to the test area along the fiber axis direction, and adjusting the lens fiber end surface to the position to be measured with the assistance of the horizontal visual monitoring unit and the vertical visual monitoring unit in the visual monitoring module 4;

[0041] S3, rotating the fiber rotating clamp 24 until the spot on the monitoring interface of the beam analyzer 32 presents the minimum ellipticity value, and the length Y in the fast axis direction of the spot reaches the maximum value and the length X in the slow axis direction reaches the minimum value, and then adjusting the five-dimensional slide table 21 so that the lens fiber end surface is in the fixed position calibrated by the horizontal visual monitoring unit and the vertical visual monitoring unit in the visual monitoring module 4, and the fiber axis is perpendicular to the detector plane and passes through the center of the detector, and the position of the lens fiber at this time is recorded as state one, the coordinate values (X1, Y1) of the spot center at state one are recorded, the sizes A1 and B1 of the spot in the fast axis and slow axis directions are recorded, and the distance D between the lens fiber end surface and the detector plane is recorded;

[0042] S4, since the fiber axis is perpendicular to the detector plane and passes through the center of the detector at the state in S3, and the distance D between the fiber end surface and the detector plane is unchanged, the computer is used to capture the coordinate values (X1, Y1) of the spot center, the sizes A1 and B1 of the spot in the fast axis and slow axis directions, and the distance D between the lens fiber end surface and the detector plane recorded in S3, and the off-axis degree Z1 of the light beam of the lens fiber in the slow axis direction is obtained by using the computer to calculate the geometric relationship between X1 and D, and the off-axis degree Z2 in the fast axis direction is obtained by calculating the geometric relationship between Y1 and D, and the divergence angle of the light beam is compensated by geometric calculation according to the off-axis degrees Z1 and Z2 and the sizes A1 and B1 of the spot, so that the divergence angles W in the fast axis and slow axis directions can be calculated.

[0043] In the application, the off-axis degree and divergence angle of the light beam of the lens fiber can be calculated by using the computer to collect the light beam parameters of the lens fiber at two position states through the positioning measurement method. If the computer is not used, other methods can also be used to calculate the off-axis degree and divergence angle of the light beam of the lens fiber based on geometric relationship calculation. The device is simple in structure, easy to use, easy to operate, simple and fast in test method, high in efficiency, and low in technical level requirement for the operator.

[0044] The present application utilizes the characteristic that the light beam analyzer 32 measures the energy field distribution of the Gaussian light beam in real time, and can measure the divergence angle and the off-axis of the fast axis and the slow axis of the lens fiber at one time. In addition, when measuring and positioning the rotating direction of the lens fiber, the present application utilizes the two-direction CCD and the ellipticity value of the light beam to comprehensively position (which can be quantified), and is more accurate.

[0045] The direction positioning in the prior measurement technology is not as accurate as the present application, and only utilizes the CCD without digital quantification. The divergence angle and the off-axis of one direction can be measured at one time.

[0046] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, and all of them should be covered in the protection scope of the present application.

Claims

1. A measuring method of a lens fiber light beam off-axis degree and divergence angle device, the lens fiber light beam off-axis degree and divergence angle device comprising a fiber clamping and fine adjustment module (2), an optical test module (3) and a visual monitoring module (4); the fiber clamping and fine adjustment module (2) comprises an adjusting mechanism and a quantifying mechanism, the adjusting mechanism is used for clamping and fine adjustment of the fiber, and the quantifying mechanism is used for recording the translation amount and rotation angle of the fiber; the fiber clamping and fine adjustment module (2) comprises a five-dimensional sliding table (21), a moving table (22), a locking block (23) and a fiber rotation clamp (24), the moving table (22) is adjustably arranged on a dovetail groove of the five-dimensional sliding table (21) and is fixed through the locking block (23), the upper end of the moving table (22) is used for fixing the fiber rotation clamp (24), the fiber rotation clamp (24) is used for rotation operation along the fiber axis direction after the locking block (23) locks the fiber, and the fiber rotation clamp (24) is provided with an angle scale for quantifying the rotation angle of the fiber, one end of the fiber with a lens is arranged on the clamping fixture of the fiber clamping and fine adjustment module (2), and the other end is connected to a pump light source; the optical test module (3) is used for detecting the light beam of the lens fiber, the visual monitoring module (4) is used for monitoring the positions of the fiber side surface in two axial directions and spatially positioning the fiber end surface, the optical test module (3) comprises a light beam analyzer base (31) and a light beam analyzer (32), the light beam analyzer base (31) is connected to the bottom plate (1), and the light beam analyzer (32) is connected to the light beam analyzer base (31), the visual monitoring module (4) comprises a horizontal visual monitoring unit and a vertical visual monitoring unit, the horizontal visual monitoring unit is used for monitoring and positioning the movement and rotation state of the lens fiber in the vertical direction, and the vertical visual monitoring unit is used for monitoring and positioning the movement and rotation state of the lens fiber in the horizontal direction, characterized in that and comprises the following steps: S1, placing the lens fiber to be measured on the fiber rotation clamp (24) so that the fiber end surface passes through the closed loop ceramic ferrule and exposes a certain fiber length; S2, using the five-dimensional sliding table (21) to send the end surface of the lens fiber to the test area along the fiber axis direction, and adjusting the lens fiber end surface to the position to be measured with the aid of the horizontal visual monitoring unit and the vertical visual monitoring unit in the visual monitoring module. S3, rotate the fiber rotating clamp (24) until the spot on the monitoring interface of the light beam analyzer (32) presents the minimum ellipticity value, and the length of the fast axis direction of the spot reaches the maximum value and the length of the slow axis direction reaches the minimum value based on the half-width of the spot intensity, fine-tune the five-dimensional slide table so that the lens fiber end face is simultaneously positioned at the fixed positions calibrated by the horizontal visual monitoring unit and the vertical visual monitoring unit in the visual monitoring module (4), record the position of the lens fiber at this time as state one, record the coordinate values of the spot center at state one, record the size of the spot in the fast axis and slow axis directions, and record the distance between the lens fiber end face and the detector plane; S4, calculate the off-axis degree of the lens fiber light beam in the fast axis and slow axis directions by capturing the spot center coordinate values, the size of the spot in the fast axis and slow axis directions, and the distance between the lens fiber end face and the detector plane recorded in step S3, and calculate the divergence angles in the fast axis and slow axis directions according to the size of the spot in the fast axis and slow axis directions.

2. The method of claim 1, wherein: The fixed position in step S3 is perpendicular to the detector plane and passes through the center of the detector.

3. The method of claim 1, wherein: The fiber clamping and fine-tuning module (2) comprises a connecting seat (25) and a closed-loop ceramic sleeve (26), the connecting seat (25) is fixed with the fiber rotating clamp (24), and the closed-loop ceramic sleeve (26) is fixed in the upper end hole of the connecting seat (25) and can insert the lens fiber for guiding and supporting the lens fiber.

4. The method of claim 1, wherein the method further comprises: measuring the beam divergence of the lensed fiber output beam. The light beam analyzer (32) is connected to the light beam analyzer base (31) in a horizontal manner through a positioning pin.

5. The method of measuring the off-axisness and the divergence angle of the light beam of a lensed fiber according to claim 1, wherein: The fiber groove, the rotation center of the fiber rotating clamp (24), the center of the closed-loop ceramic sleeve (26), and the center of the sensor of the light beam analyzer (32) are on the same axis and coincide with the fiber axis.

6. The method of measuring the off-axisness and the divergence angle of the light beam of a lensed fiber according to claim 1, wherein: The horizontal visual monitoring unit comprises a vertical fixed seat (41), a lens barrel fixing frame one (42), and a CCD microscope one (43), and the CCD microscope one (43) is connected to the vertical fixed seat (41) through the lens barrel fixing frame one (42); The vertical visual monitoring unit comprises a vertical support (44), a horizontal adjustment plate (45), a lens barrel fixing frame two (46), and a CCD microscope two (47), the CCD microscope two (47) is arranged on the horizontal adjustment plate (45) through the lens barrel fixing frame two (46), and the horizontal adjustment plate (45) is used for adjusting the relative position between the lens barrel fixing frame two (46) and the vertical support (44).

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