An adjustable fiber ratio fiber optic light source for astronomical fiber ratio degradation property measurements

Abstract

The application discloses a kind of adjustable focal ratio fiber optic light sources for astronomical fiber focal ratio degradation property measurement, it is related to fiber optic light source technical field, including base, light source, first clamp, hollow container, second clamp, controllable pressure ware, optical fiber, flange, flat slide and electric control system, the base is slidably connected in the inside of flat slide, the light source and first clamp are respectively fixed on flat slide, the second clamp is fixed on the top of flat slide, the first clamp and second clamp can be fixed with optical fiber, the hollow container is located between first clamp and second clamp, the hollow container is set on flat slide, the flange is set on the top of flat slide far from the one end of base.The application input focal ratio parameter, electric control system can automatically adjust the microbending and pressure degree of optical fiber to obtain the corresponding focal ratio of exit light, convenient operation, coupling between optical fiber is carried out through flange, and almost isolates the interference of ambient light.

Description

Technical Field

[0001] This invention relates to the field of fiber optic light source technology, and in particular to an adjustable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers. Background Technology

[0002] The fiber focal ratio refers to the ratio of the diameter D of the light spot perpendicular to the emission direction to the distance F of that spot from the fiber end face, f = F / D. Ideally, under numerical aperture constraints, the emission focal ratio of the fiber should be the same as the incident focal ratio. However, in reality, due to factors such as fiber bending and end face treatment, the emission focal ratio is always smaller than the incident focal ratio, resulting in a more divergent beam. Since the first fiber-based astronomical instrument was used, the degradation of the fiber focal ratio, leading to greater dispersion of light energy, has consistently affected the efficiency and accuracy of spectroscopic observations. Although the focal ratio degradation characteristic of fibers cannot be completely eliminated, it is essential to minimize and understand the numerical value of focal ratio degradation in order to design and optimize the overall astronomical spectroscopic observation system.

[0003] There are currently two main methods for measuring focal ratio degradation, such as Figure 3 As shown, 1 is the fiber optic light source, 2 and 4 are apertures, 3 and 5 are lenses, 6-7 are the fiber under test, 8 is a CCD, and 9 is the program processing. The principle is that the light source 1 generates parallel light through 3, the parallel light is converged through 5, and 6 is placed at the focal point of 5 to achieve the effect of light coupling into the fiber. Among them, 4 controls the range of incident light and determines the incident focal ratio. Method 1 simulates the working state of a telescope, where a circular range of parallel light is converged into the fiber through the lens. The result of the output focal ratio at 7 is expressed as 90% of the total output light energy can be collected within a certain output focal ratio range, corresponding to the actual performance of the fiber in the instrument. Method 2 uses a collimated beam at a given angle to be incident on the fiber, and the result is expressed as the full width at half maximum (FWHM) of the output ring, which corresponds to the degree of dispersion of the transmission mode of the fiber at that specific angle.

[0004] However, the methods described above all use lenses to converge and couple parallel light into the optical fiber. The process from generating parallel light to coupling spatial light into the fiber requires a complex collimation optical path, resulting in a large size and inconvenience for portability. Spatial light coupling into the fiber involves focusing parallel light onto the fiber end face using a lens. Depending on the lens used, the distance between the two is typically between 25-100 mm. However, the core diameter of astronomical specialty optical fibers is tens to hundreds of micrometers, making the system's anti-interference capability poor. Especially when replacing the test fiber, even slight vibrations can cause the incident light to deviate from the center of the fiber under test, thus indicating room for improvement. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies by proposing an adjustable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers. Its advantages include the ability of the electronic control system to automatically adjust the micro-bending and pressure applied to the fiber to obtain the corresponding focal ratio output light after inputting the focal ratio parameter, facilitating operation; and fiber-to-fiber coupling via a flange, virtually isolating interference from ambient light.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An adjustable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers includes a base, a light source, a first clamp, a hollow container, a second clamp, a controllable pressure device, an optical fiber, a flange, a straight slide rail, and an electrical control system.

[0008] The base is slidably connected to the inside of the straight slide rail. The light source and the first clamp are respectively fixed on the straight slide rail. The second clamp is fixed above the straight slide rail. The first clamp and the second clamp can jointly fix the optical fiber. The hollow container is located between the first clamp and the second clamp. The hollow container is set on the straight slide rail. The flange is set on the top of the straight slide rail away from the base. The controllable pressure device is located between the second clamp and the flange. The controllable pressure device is used to apply a specified pressure to the optical fiber locally. The electronic control system is used to control the displacement of the base and the pressure applied by the controllable pressure device.

[0009] The invention is further configured such that the interior of the hollow container has a flat structure. This flat structure design allows for the storage of the micro-bends of the optical fiber, improving the fiber storage efficiency.

[0010] The invention is further configured such that both the first and second clamps have a rubber layer inside, and the rubber layer is in direct contact with the optical fiber. The rubber layer ensures that pressure is applied evenly to the surface of the optical fiber, preventing single-point pressure from causing additional focal ratio degradation and optical fiber damage.

[0011] The present invention is further configured such that the optical fiber is wound counterclockwise around a circle inside the hollow container, and the degree of micro-bending of the optical fiber can be controlled by controlling the radius of curvature of the optical fiber winding.

[0012] The present invention is further configured such that when the optical fiber is used for light extraction, an FC / PC optical fiber connector needs to be made and connected to a flange.

[0013] The present invention is further configured such that the output focal ratio of the optical fiber is negatively correlated with the magnitude of the pressure and the degree of microbending of the optical fiber. The output optical fiber is subjected to a specific pressure by a controllable pressure device, and a specific microbending is applied to the microbending part, so as to generate output light with a specified focal ratio at the output end, which can be used as the input of the optical fiber under test. The applied pressure and the degree of microbending are controlled by the electronic control system according to the specified focal ratio.

[0014] The present invention is further configured such that the FC / PC connector of the optical fiber and the output optical fiber connector are coaxially aligned, and both the FC / PC connector and the output optical fiber connector are located inside the flange.

[0015] The present invention is further configured such that the core diameter of the optical fiber is d1, the core diameter of the output optical fiber is d2, the distance L between the optical fiber end faces on both sides of the flange, and the set focal ratio f satisfy a certain mathematical relationship; during light transmission, the light emitted from each point of the output optical fiber core is required to enter the core of the optical fiber under test. Given the focal ratio f, the diameter of the light spot at a distance L from the surface of the output optical fiber core is d = d2 + L / f. d should be less than d1, so L < (d1 - d2) * f.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. In common spatial light systems, the aperture size needs to be precisely adjusted to change the focal ratio. This invention changes the length of the optical fiber in the hollow container by moving the base, thereby controlling the bending degree of the coiled optical fiber in the hollow container and controlling the pressure applied to the optical fiber by the controllable pressure device. The two work together to achieve the purpose of controlling the output focal ratio. In actual use, the optical fiber to be tested is connected to the flange to achieve the light incident at the specified focal ratio. After inputting the focal ratio parameter, the electronic control system can automatically adjust the micro-bending and pressure degree of the optical fiber to obtain the output light of the corresponding focal ratio, which is convenient to operate.

[0018] 2. Commonly used spatial light systems are bulky and difficult to carry. In this invention, all parts are fixed on a slide rail, and except for the fiber micro-bending which requires a certain amount of space, the other components are small in size and light in weight, making them easy to carry and convenient for focal ratio degradation detection in non-laboratory environments.

[0019] 3. The present invention uses a flange to connect the fiber optic output to one end of the fiber under test, which ensures stable incident signal, strong anti-interference capability, and convenient replacement of the fiber under test, thereby improving the efficiency of focal ratio degradation measurement.

[0020] 4. Light is transmitted in optical fibers and coupled between fibers through flanges, which almost completely isolates it from the interference of ambient light. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of an adjustable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers, as proposed in this invention.

[0022] Figure 2 This is a schematic diagram of the position structure of the light source and the fiber under test in an adjustable focal ratio fiber light source for measuring the focal ratio degradation properties of astronomical optical fibers proposed in this invention.

[0023] Figure 3 This is a schematic diagram of the optical path structure of the fiber optic light source in the prior art of this invention.

[0024] In the diagram: 1. Base; 2. Light source; 3. First clamp; 4. Hollow container; 5. Second clamp; 6. Controllable pressure device; 7. Optical fiber; 8. Flange; 9. Straight slide rail; 10. Electrical control system. Detailed Implementation

[0025] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0026] The embodiments of this patent 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 are only used to explain this patent, and should not be construed as limiting this patent.

[0027] Reference Figure 1 An adjustable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers includes a base 1, a light source 2, a first clamp 3, a hollow container 4, a second clamp 5, a controllable pressure device 6, an optical fiber 7, a flange 8, a straight slide rail 9, and an electrical control system 10.

[0028] The base 1 is slidably connected to the inside of the straight slide rail 9. The light source 2 and the first clamp 3 are respectively fixed on the straight slide rail 9. The second clamp 5 is fixed above the straight slide rail 9. The first clamp 3 and the second clamp 5 can jointly fix the optical fiber 7. The hollow container 4 is located between the first clamp 3 and the second clamp 5. The hollow container 4 is set on the straight slide rail 9. The flange 8 is set on the top of the straight slide rail 9 at the end away from the base 1. The controllable pressure device 6 is located between the second clamp 5 and the flange 8. The controllable pressure device 6 is used to apply a specified pressure to the optical fiber 7 locally. The electrical control system 10 is used to control the displacement of the base 1 and the pressure applied by the controllable pressure device 6.

[0029] In this embodiment, the interior of the hollow container 4 is a flat structure. The flat structure design can be used to store the micro-bent portion of the optical fiber 7, which improves the storage effect of the optical fiber 7. The interior of the first clamp 3 and the second clamp 5 are both provided with a rubber layer. The rubber layer is in direct contact with the optical fiber 7. The rubber layer allows the pressure to be applied evenly to the surface of the optical fiber 7, avoiding single-point pressure that could cause additional focal ratio degradation and damage to the optical fiber 7.

[0030] The optical fiber 7 is wound counterclockwise around the hollow container 4. The degree of micro-bending of the optical fiber can be controlled by controlling the radius of curvature of the optical fiber winding. When the optical fiber 7 is used to extract light, an FC / PC optical fiber connector needs to be made and connected to the flange 8.

[0031] Furthermore, the output focal ratio of the optical fiber 7 is negatively correlated with the magnitude of the pressure and the degree of microbending of the optical fiber 7. The output optical fiber 7 is subjected to a specific pressure by the controllable pressure device 6, and a specific microbending is applied to the microbending part, which can generate output light with a specified focal ratio at the output end, which can be used as the input of the optical fiber 7 under test. The applied pressure and the degree of microbending are controlled by the electronic control system 10 according to the specified focal ratio.

[0032] It is worth mentioning that, referring to Figure 2 The FC / PC connector of fiber 7 is coaxially aligned with the output fiber connector. Both the FC / PC connector and the output fiber connector are located inside the flange 8, ensuring the quality of coupling. The core diameter of fiber 7 is d1, and the core diameter of the output fiber is d2. The distance L between the end faces of fiber 7 on both sides of the flange 8 and the set focal ratio f satisfy a certain mathematical relationship. During light transmission, the light emitted from each point of the output fiber core must be able to enter the core of the fiber under test. Given the focal ratio f, the diameter of the light spot at a distance L from the surface of the output fiber core is d = d2 + L / f. d should be less than d1, so L < (d1 - d2) * f, ensuring that all the light emitted from the output fiber can enter the fiber under test.

[0033] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A tunable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers, characterized in that, It includes a base (1), a light source (2), a first clamp (3), a hollow container (4), a second clamp (5), a controllable pressure device (6), an optical fiber (7), a flange (8), a straight slide rail (9), and an electrical control system (10). The base (1) is slidably connected to the inside of the flat slide rail (9). The light source (2) and the first clamp (3) are respectively fixed on the flat slide rail (9). The second clamp (5) is fixed above the flat slide rail (9). The first clamp (3) and the second clamp (5) can jointly fix the optical fiber (7). The hollow container (4) is located between the first clamp (3) and the second clamp (5). The hollow container (4) is set on the flat slide rail (9). The flange (8) is set on the top of the flat slide rail (9) away from the base (1). The controllable pressure device (6) is located between the second clamp (5) and the flange (8). The controllable pressure device (6) is used to apply a specified pressure to the optical fiber (7) locally. The electrical control system (10) is used to control the displacement of the base (1) and the pressure applied by the controllable pressure device (6). The inside of the hollow container (4) is a flat structure. The design can be used to store the micro-bent portion of the optical fiber (7), which improves the storage effect of the optical fiber (7). The first clamp (3) and the second clamp (5) are both provided with rubber layers inside, and the rubber layers are in direct contact with the optical fiber (7). The rubber layer allows the pressure to be applied evenly to the surface of the optical fiber (7), avoiding single-point pressure causing additional focal ratio degradation and optical fiber (7) damage. The optical fiber (7) is rotated counterclockwise around the hollow container (4). The degree of micro-bending of the optical fiber (7) can be controlled by controlling the radius of curvature of the optical fiber (7). The output focal ratio of the optical fiber (7) and the magnitude of the pressure and the degree of micro-bending of the optical fiber (7) are negatively correlated. The output optical fiber is subjected to a specific pressure by a controllable pressure device (6), and the micro-bending portion is subjected to a specific micro-bending, which can generate output light with a specified focal ratio at the output end as the input of the optical fiber under test. The applied pressure and the degree of micro-bending are controlled by the electronic control system (10) according to the specified focal ratio.

2. The adjustable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers according to claim 1, characterized in that, When the optical fiber (7) is used for light extraction, an FC / PC optical fiber connector needs to be made and connected to the flange (8).

3. The adjustable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers according to claim 1, characterized in that, The FC / PC connector of the optical fiber under test is coaxially aligned with the output optical fiber connector, and both the FC / PC connector and the output optical fiber connector are located inside the flange (8).

4. The adjustable focal ratio fiber optic light source for measuring the focal ratio degradation properties of astronomical optical fibers according to claim 3, characterized in that, The core diameter of the fiber under test is d1, and the core diameter of the output fiber is d2. The distance L between the fiber end faces on both sides of the flange (8) and the set focal ratio f satisfy a certain mathematical relationship. During light transmission, the light emitted from each point of the output fiber core must be able to enter the fiber core of the fiber under test. Given the focal ratio f, the diameter of the light spot at a distance L from the surface of the output fiber core is... d should be less than d1, therefore .

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