A high refractive index glue reliability test apparatus and method

Abstract

The application discloses a high-refractive-index glue reliability testing device and method. The testing device comprises a temperature detector, an optical power meter and sequentially fused light beam injection unit, a multimode optical fiber and a single-mode optical fiber. The multimode optical fiber and the single-mode optical fiber are provided with a high-refractive-index glue layer to be tested at a fusion point. The input end of the temperature detector is aligned with the high-refractive-index glue layer to be tested to monitor the temperature in real time. The optical power meter is arranged at the output end of the single-mode optical fiber to test the output power of the optical path. The reliability testing method is executed by the device. The device and method can test the reliability of the high-refractive-index glue to be tested in the laser field application process.

Description

Technical Field

[0001] This application belongs to the field of adhesive performance testing technology, specifically relating to a high refractive index adhesive reliability testing device and method. Background Technology

[0002] Due to the unique structure of all-fiber lasers, residual pump light, amplified spontaneous emission, and signal light leaked due to fiber bending are unavoidable in the fiber cladding. This cladding light significantly degrades the laser beam quality and can even damage some fiber components in the laser system, thus severely affecting the stability of the fiber laser. Existing technologies often employ cladding strippers to remove the cladding light from the fiber cladding, thereby reducing its damage to fiber components.

[0003] Currently, high-refractive-index adhesives are commonly used in fiber lasers for cladding stripping. As the output power of fiber lasers continues to increase, the power of residual pump light and higher-order lasers is also constantly increasing. Therefore, the reliability assessment of high-refractive-index adhesives used for cladding stripping in lasers plays an important role in their application.

[0004] Typically, reliability testing of high-refractive-index adhesives used for cladding stripping includes, but is not limited to, reliability tests under conditions such as high temperature and high power. The reliability performance evaluation indicators for the high-refractive-index adhesive under test include, but are not limited to, the maximum power it can withstand and its stripping efficiency. In the industry, the testing of these performance characteristics of high-refractive-index adhesives is often based on test reports provided by the adhesive supplier, i.e., long-term laser aging tests. This testing method not only wastes a lot of resources but also only provides information on the performance of the high-refractive-index adhesive under the corresponding laser temperature, wavelength, and power. When changing high-refractive-index adhesive suppliers or using higher-power products, a new round of preliminary testing of the high-refractive-index adhesive's performance is required, which is a cumbersome process.

[0005] Therefore, a new testing device and method are needed to test the reliability of high refractive index adhesives more efficiently and conveniently. Summary of the Invention

[0006] The purpose of this application is to provide a testing device and method for the reliability of high refractive index adhesives, addressing the shortcomings of existing technologies. This aims to solve the problems of cumbersome testing procedures and extremely low testing efficiency in existing high refractive index adhesive reliability testing.

[0007] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0008] A high refractive index adhesive reliability testing device includes a temperature detector, an optical power meter, and a beam injection unit, a multimode fiber, and a single-mode fiber that are sequentially fused together. The high refractive index adhesive layer to be tested is disposed at the fusion point of the multimode fiber and the single-mode fiber. The input end of the temperature detector is aligned with the high refractive index adhesive layer to be tested for real-time temperature monitoring. The optical power meter is disposed at the output end of the single-mode fiber for testing the output power of the optical path.

[0009] As a preferred embodiment, the beam injection unit has a pigtail, which is a single-mode power transmission fiber.

[0010] As a preferred option, the pigtail, multimode fiber, and single-mode fiber are sequentially fused without eccentricity.

[0011] As a preferred option, the output end of the single-mode fiber is beveled.

[0012] As a preferred option, the tilt angle of the bevel is 6°-9°.

[0013] As a preferred option, the outer periphery of the fiber cladding at the splice point is directly coated with a high refractive index adhesive layer to be tested.

[0014] This application also proposes a reliability testing method for high refractive index adhesives, executed by the testing apparatus of any of the above schemes, including:

[0015] S1. Fusion splice the pigtail of the beam injection unit to the input end of the multimode fiber, and fusion splice the single-mode fiber to the output end of the multimode fiber.

[0016] S2. Apply the high refractive index adhesive to be tested to the fusion splice of the single-mode fiber and the multimode fiber, cure it, and cut the output end face of the single-mode fiber at an angle.

[0017] S3. Adjust the beam injection unit to stabilize its input power at P1, test the output power of the optical path at P2, and record the temperature T1 of the high refractive index adhesive layer under test at this time;

[0018] S4. Turn off the beam injection unit. After a predetermined time, gradually increase the input power of the beam injection unit. Repeat step S3 until the high-refractive-index adhesive under test begins to burn off. Record the input power P of the beam injection unit at this time. n ;

[0019] S5. When the input power of the beam injection unit is P1, the optical stripping efficiency of the high refractive index adhesive to be tested is: .

[0020] As a preferred embodiment, after step S2 is executed and before step S3 is executed, the initial temperature T0 of the high refractive index adhesive layer to be tested is detected.

[0021] As a preferred option, the predetermined time is the time required for the temperature of the high refractive index adhesive to be tested to drop from T1 to T0.

[0022] As a preferred embodiment, step S5 further includes deriving the linear / nonlinear relationship between the two based on the multiple sets of power values ​​and temperature values ​​recorded in steps S3 and S4.

[0023] Compared with existing technologies, the beneficial effects of this application are as follows: By fusion splicing multimode and single-mode fibers, and utilizing the mode field diameter mismatch principle, the light beam enters the multimode fiber from the pigtail of the light source, exciting as many higher-order modes as possible. Then, the beam enters the single-mode fiber from the multimode fiber, allowing the higher-order modes, optical loss at the splice point, and cladding light in the multimode fiber to be filtered out by the cured high-refractive-index adhesive coated on its outer cladding surface. Furthermore, by setting different input powers for the beam injection unit and testing the temperature of the high-refractive-index adhesive layer after a predetermined time, the linear / nonlinear relationship between the power the adhesive can withstand and its temperature, as well as the upper limit of the optical power the adhesive can withstand, can be obtained, thereby enabling the testing of the reliability of the high-refractive-index adhesive. This invention filters out as much light as possible through the adhesive under test in a simple way, allowing for efficient and convenient measurement of the adhesive's reliability. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of a method for testing the reliability of high refractive index adhesives in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the high refractive index adhesive reliability testing device in an embodiment of the present invention.

[0027] Reference numerals in the attached diagram: 1. Beam injection unit; 2. Pigtail; 3. Multimode fiber; 4. Fusion splice; 5. Single-mode fiber; 6. Optical power meter; 7. Temperature detector. Detailed Implementation

[0028] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0029] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] like Figure 1 As shown, this invention relates to a high-refractive-index adhesive reliability testing device and method. The testing device includes, but is not limited to, a temperature detector 7, an optical power meter 6, and a beam injection unit 1, a multimode fiber 3, and a single-mode fiber 5 sequentially fused together. The beam injection unit 1 emits a test beam into the multimode fiber 3; a layer of high-refractive-index adhesive to be tested is provided at the splice point 4 between the multimode fiber 3 and the single-mode fiber 5 to remove stray light from the optical path; the input end of the temperature detector 7 is aligned with the high-refractive-index adhesive layer to be tested for real-time temperature monitoring; the optical power meter 6 is located at the output end of the single-mode fiber 5 to test the output power of the optical path.

[0032] Please continue to refer to Figure 1 The beam injection unit 1 has a pigtail 2, which is a single-mode power transmission fiber. The beam injection unit 1 is directly fused to the input end of the multimode fiber 3 through the pigtail 2; the output end of the multimode fiber 3 is fused to the single-mode fiber 5, and the fusion point 4 is provided at the fusion point 4, where the high refractive index adhesive layer to be tested is provided.

[0033] Optionally, in the embodiments of this application, the beam injection unit 1 includes, but is not limited to, fiber lasers, semiconductor lasers, solid-state lasers, and lasers modified from the above-mentioned lasers. This application does not specifically limit the types of lasers used.

[0034] Optionally, in the embodiments of this application, the pigtail, multimode fiber, and single-mode fiber can all be single-clad fibers or double-clad fibers. This application does not impose specific limitations on this.

[0035] Specifically, at the splice point between multimode fiber 3 and single-mode fiber 5, the coating layer on the outside of the fiber cladding is stripped off, and the outer periphery of the cladding is directly covered with the high refractive index adhesive layer to be tested.

[0036] In an embodiment of the present invention, the core diameter of the pigtail 2 (i.e., single-mode transmission fiber) of the beam injection unit 1 is smaller than the core diameter of the multimode fiber 3; in order to excite a sufficient number of higher-order modes, the core diameter of the multimode fiber 3 is in the range of 50-100 μm; in order to filter out higher-order modes, the core diameter of the single-mode fiber 5 is in the range of 5-20 μm.

[0037] It should be noted that the pigtail 1, multimode fiber 3, and single-mode fiber 5 of the beam injection unit are fused together without eccentricity, and the three fiber segments have the same axis after fusion. Due to the mismatch in mode field diameters between multimode fiber 3 and single-mode fiber 5, at the fusion point 4 between multimode fiber 3 and single-mode fiber 5, not only are the cladding light and the loss light caused by fusion stripped from multimode fiber 3, but the higher-order modes in the core of multimode fiber 3 are also stripped from the high-refractive-index adhesive layer to the outside of the fiber.

[0038] Specifically, when the light beam propagates in the pigtail 2 of the beam injection unit 1, only the fundamental mode of that wavelength exists in the fiber core. When the light in pigtail 2 (single-mode transmission fiber) propagates to multimode fiber 3, a mode field mismatch effect occurs due to the difference in core diameter between the two fibers. This causes the fundamental mode in the single-mode transmission fiber to be excited into multiple higher-order modes in the multimode fiber 3, and these higher-order modes dominate the core. After the transmission mode field stabilizes in the multimode fiber, a mode field mismatch reappears at the fusion splice between the output end of the multimode fiber 3 and the input end of the single-mode fiber 5. All higher-order modes are stripped and pass through the high-refractive-index adhesive layer at the fusion splice point 4 between the multimode fiber 3 and the single-mode fiber 5.

[0039] Optionally, the output end face of the single-mode fiber 5 is beveled to suppress beam reflection from the end face.

[0040] Optionally, the tilt angle of the oblique angle is 6°-9° to better suppress end face reflection and reduce the error of the actual received power, preferably 8°.

[0041] The present invention also proposes a reliability testing method for high refractive index adhesives, which is specifically performed by the aforementioned testing device.

[0042] As one specific embodiment, please refer to Figure 2 The testing method for the reliability of high refractive index adhesives includes the following steps:

[0043] S1. Fusion splice the pigtail of the beam injection unit to the input end of the multimode fiber, and fusion splice the single-mode fiber to the output end of the multimode fiber.

[0044] S2. Apply the high refractive index adhesive to be tested to the fusion splice of the single-mode fiber and the multimode fiber, cure it, and cut the output end face of the single-mode fiber at an angle.

[0045] S3. Adjust the beam injection unit to stabilize its input power at P1, test the output power of the optical path at P2, and record the temperature T1 of the high refractive index adhesive layer under test at this time;

[0046] S4. Turn off the beam injection unit. After a predetermined time, gradually increase the input power of the beam injection unit. Repeat step S3 until the high-refractive-index adhesive under test begins to burn off. Record the input power P of the beam injection unit at this time. n ;

[0047] S5. When the input power of the beam injection unit is P1, the optical stripping efficiency of the high refractive index adhesive to be tested is: .

[0048] In the above test process, the difference between the input optical power P1 and the output optical power P2 is the optical power value stripped from the high refractive index adhesive layer under test, specifically including:

[0049] 1. Multiple higher-order modes excited from multimode fiber;

[0050] 2. Optical power loss at the fusion splice between multimode and single-mode optical fibers;

[0051] 3. Cladding light at the high refractive index adhesive coating of multimode and single-mode optical fibers.

[0052] Understandably, in this testing system, as the input power of the beam injection unit 1 increases, the optical power for stripping the high-refractive-index adhesive at the weld point 4 also increases. However, once the temperature reaches a certain threshold, the effectiveness of this adhesive stripping optical power begins to decline. Therefore, during the testing of the optical stripping efficiency of high-refractive-index adhesive, it is necessary to test the limit input power of the beam injection unit 1 to control the adhesive temperature below this threshold, thereby ensuring the accuracy of the stripping efficiency result measured in step S5.

[0053] Specifically, in step S2, the output end face of the single-mode fiber 5 is beveled to suppress beam reflection from the end face. The bevel angle is 6°-9° to better suppress end face reflection and reduce the error of the actual received power, preferably 8°.

[0054] After the device is assembled, the initial temperature T0 of the high refractive index adhesive layer to be tested is measured. The power of the beam injection unit 1 is adjusted and maintained at a certain power P1 for a period of time to ensure a relatively stable output. The output power P2 of the optical path is tested, and the temperature T1 of the high refractive index adhesive layer to be tested is recorded at this time.

[0055] During the testing process in this embodiment of the invention, the high-refractive-index adhesive layer under test refracts the absorbed light out of the cladding, leaving residual heat energy in the adhesive layer. Therefore, before the test begins, a temperature detector 7 is used to detect the initial temperature value of the high-refractive-index adhesive layer under test, so as to facilitate subsequent research on the linear / nonlinear relationship between the power absorbed by the high-refractive-index adhesive under test and its temperature.

[0056] Optionally, the temperature detector 7 may include, but is not limited to, a thermal imager, an infrared thermometer, etc.

[0057] After the initial temperature and optical output power tests of the high-refractive-index adhesive layer are completed, beam injection unit 1 is turned off, and the temperature of the high-refractive-index adhesive under test is allowed to drop from T1 to T0. The input power of beam injection unit 1 is gradually increased, and step S3 is repeated until the high-refractive-index adhesive under test begins to burn. The input power P of beam injection unit 1 at this time is recorded. n .

[0058] To enhance the safety of light source operation, the input power of beam injection unit 1 is adjusted to increase gradually and systematically. For example, the initial output power of beam injection unit 1 is set to 10% of P1. The reading of optical power meter 6 is observed, and the power is continuously increased in increments of 10% of P1 until the reading of optical power meter 6 is exactly P1. This operation not only ensures the safety of power adjustment of beam injection unit 1 but also ensures the accuracy of the optical power value output from the pigtail 2 of beam injection unit 1. Furthermore, optical power meter 6 is aligned with the output end of single-mode fiber 5 to test the output power P2 of the beam emitted from the output end of single-mode fiber 5. From this, the optical stripping efficiency of the high-refractive-index adhesive under test can be obtained as follows: .

[0059] It is understood that, in the embodiments of the present invention, as much of the light input from the beam injection unit 1 is converted into light that can be stripped away by the high refractive index adhesive layer under test, thereby quantifying the light stripping efficiency of the high refractive index adhesive layer under test.

[0060] The purpose of waiting for the temperature of the high-refractive-index adhesive layer to drop to its initial temperature T0 is to: keep the initial temperature of the high-refractive-index adhesive layer constant, change the input power, and measure the operating temperature of the high-refractive-index adhesive layer at this power. Then, repeat step S4 to measure the temperature values ​​of the high-refractive-index adhesive layer under multiple sets of different input powers until the high-refractive-index adhesive layer begins to burn out. This allows us to obtain the linear / non-linear relationship between its withstand power and temperature, as well as the maximum withstand power of the high-refractive-index adhesive layer.

[0061] Compared with the prior art, the solution of the present invention has the following advantages:

[0062] 1. By fusion splicing multimode fiber and single-mode fiber, and utilizing the mode field mismatch principle, the test beam enters the multimode fiber from the pigtail of the beam injection unit, exciting as many higher-order modes as possible. Then, it enters the single-mode fiber from the multimode fiber. This allows the higher-order modes, the loss light generated at the splice point, and the cladding light at the high-refractive-index adhesive coating to be filtered out from the cured high-refractive-index adhesive layer coated on its outer cladding surface. This allows for a simple and efficient measurement of the adhesive stripping efficiency.

[0063] 2. By controlling the beam injection unit to output different input powers and testing the temperature of the high refractive index adhesive layer under test after a period of time, the linear / nonlinear relationship between the power that the adhesive can withstand and its temperature, as well as the upper limit of the optical power that the adhesive can withstand, can be obtained.

[0064] This invention filters out as much light as possible through the high-refractive-index adhesive being tested in a simple way, which can accurately measure the reliability of the adhesive being tested, and is efficient and convenient.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A reliability testing device for high refractive index adhesives, characterized in that, It includes a temperature detector (7), an optical power meter (6), and a beam injection unit (1), a multimode fiber (3), and a single-mode fiber (5) that are fused together in sequence. The beam injection unit (1) has a pigtail (2), which is a single-mode power transmission fiber. The beam injection unit (1) is directly fused to the input end of the multimode fiber (3) through the pigtail (2). The core diameter of the pigtail (2) is smaller than the core diameter of the multimode fiber (3). The output end of the multimode fiber (3) is fused to the single-mode fiber (5). At the splice point (4) between the multimode fiber (3) and the single-mode fiber (5), the coating layer outside the fiber cladding is stripped off, and the outer periphery of the cladding is directly covered with the high refractive index adhesive layer to be tested. The input end of the temperature detector (7) is aligned with the high refractive index adhesive layer to be tested for real-time temperature monitoring. The optical power meter (6) is located at the output end of the single-mode optical fiber (5) for testing the output power of the optical path.

2. The testing apparatus according to claim 1, characterized in that, The pigtail (2), the multimode fiber (3), and the single-mode fiber (5) are sequentially spliced ​​without eccentricity.

3. The testing apparatus according to claim 1, characterized in that, The output end of the single-mode fiber (5) is beveled.

4. The testing apparatus according to claim 3, characterized in that, The tilt angle of the oblique angle is 6°-9°.

5. A reliability testing method for high refractive index adhesives, characterized in that, Performed by the testing apparatus as described in any one of claims 1-4, comprising: S1. The pigtail of the beam injection unit is fused to the input end of the multimode fiber, and the single-mode fiber is fused to the output end of the multimode fiber. S2. Apply the high refractive index adhesive to be tested to the fusion splice of the single-mode fiber and the multimode fiber, cure it, and cut the output end face of the single-mode fiber at a bevel. S3. Adjust the beam injection unit to stabilize its input power at P1, test the output power of the optical path at P2, and record the temperature T1 of the high refractive index adhesive layer under test at this time; S4. Turn off the beam injection unit. After a predetermined time, gradually increase the input power of the beam injection unit and repeat step S3 until the high refractive index adhesive under test begins to burn off. Record the input power P of the beam injection unit at this time. n ; S5. When the input power of the beam injection unit is P1, the optical stripping efficiency of the high refractive index adhesive to be tested is: .

6. The test method according to claim 5, characterized in that, After step S2 is executed and before step S3 is executed, the initial temperature T0 of the high refractive index adhesive layer to be tested is detected.

7. The test method according to claim 5, characterized in that, The predetermined time is the time required for the temperature of the high refractive index adhesive to be tested to drop from T1 to T0.

8. The test method according to claim 5, characterized in that, Step S5 also includes determining the linear / nonlinear relationship between the two based on the multiple sets of power values ​​and temperature values ​​recorded in steps S3 and S4.

Images