Method and system for monitoring non-destructive winding of hollow-core microstructured optical fiber loop

Abstract

A method and system for monitoring non-destructive winding of a hollow-core microstructured optical fiber loop, relating to the technical field of fiber-optic gyroscopes. The method comprises the following steps: performing symmetrical winding on a hollow-core microstructured optical fiber by means of a winding device; subjecting the winding device to incidence of a light wave having a high extinction ratio, and collecting an emergent signal during emission; and performing waveform analysis on the emergent signal in real time during winding, so as to monitor the non-destructive winding.

Description

A kind of hollow microstructure optical fiber ring non-destructive winding monitoring method and system

[0001] Related applications

[0002] The present application claims priority to the Chinese patent application No. 202411070000.9 filed on August 6, 2024, and incorporates by reference the entire disclosure of the above patent application as part of the present application. TECHNICAL FIELD

[0003] The present application belongs to the technical field of fiber-optic gyroscope, and in particular relates to a kind of hollow microstructure optical fiber ring non-destructive winding monitoring method and system. BACKGROUND

[0004] A fiber-optic gyroscope is an angular rate sensor based on the Sagnac effect, using optical fiber as the sensing medium, mainly applied to inertial autonomous navigation systems, and has been widely used in sea, land, air and space. With the continuous expansion of fiber-optic gyroscopes in fast temperature change, large magnetic field and high radiation application environments, the environmental response characteristics of the gyroscope fiber such as temperature, magnetic field and radiation are significantly different from the previous high-stability light guiding requirements. Traditional gyroscope fibers use quartz cores to guide light, which are limited by the ultimate thermal / optical properties of the core medium, and it is difficult to achieve this requirement by improving the physical properties of solid materials.

[0005] Hollow microstructure optical fibers are based on a new air core light guiding mechanism constructed by a specific microstructure cladding, efficiently confine light waves in air core (i.e. air in hollow core optical fiber) for transmission, using air as the light guiding medium, which significantly reduces the influence of the environment on the light waves such as heat, magnetism and radiation, and enables ideal high-stability light transmission, fundamentally solving the high-stability light guiding problem of fiber-optic gyroscope temperature and environmental adaptability. Hollow microstructure optical fibers are air holes arranged along the axial direction of the entire fiber on a single dielectric material (usually pure silica material), which are the ideal light guiding and sensing base materials for the next generation of fiber-optic gyroscopes.

[0006] Hollow microstructure optical fibers need to be precisely wound into a ring for application in fiber-optic gyroscopes, forming a fiber ring as a sensing element that directly senses the Sagnac phase shift in the gyroscope. Compared with traditional solid core optical fibers, hollow microstructure optical fibers have a hollow thin-walled microstructure inside, and various additional stresses (including fiber torsion stress, transverse extrusion stress and winding bending stress, etc.) generated during the operation of forming the fiber ring will cause the microstructure inside the hollow optical fiber to deform, destroy the construction effect of the air core light guiding mechanism, and degrade the transmission quality of light waves in the air core such as transmission loss and extinction ratio, which are key optical indicators, ultimately affecting the performance of the hollow microstructure optical fiber gyroscope. SUMMARY

[0007] The application is directed to the problem that the light guiding quality of the hollow microstructure optical fiber is easily deteriorated during the winding process of the hollow microstructure optical fiber into a ring, and proposes a kind of non-destructive winding monitoring method and system for the hollow microstructure optical fiber ring, which helps to repair the winding defects in time to avoid the problem of light guiding quality deterioration, and achieves the effect of non-destructive winding of the hollow microstructure optical fiber into a ring.

[0008] A kind of non-destructive winding monitoring method for the hollow microstructure optical fiber ring, comprising the following steps:

[0009] The hollow microstructure optical fiber is wound by the symmetric winding method through the winding equipment;

[0010] The high extinction ratio light wave is incident on the winding equipment, and the outgoing signal is collected at the outgoing port;

[0011] The outgoing signal is analyzed in real time during the winding process to realize non-destructive winding monitoring.

[0012] Further, the symmetric winding method is to sequentially wind the two fiber supply wheels onto the ring skeleton, select the first fiber supply wheel for fiber unwinding operation, and the second fiber supply wheel rotates with the main shaft of the winding equipment, and the working positions of the two fiber supply wheels are alternated until the winding of the ring is completed.

[0013] Further, the symmetric winding method is a four-pole winding method.

[0014] Further, the method for the high extinction ratio light wave incident on the winding equipment is:

[0015] The high extinction ratio light wave emitted by the polarization maintaining broadband light source is transmitted to the input port of the stator end of the double-channel fiber rotary connector, and the light wave is emitted at the output port of the rotor end of the double-channel fiber rotary connector and coupled into the winding equipment.

[0016] Further, the outgoing signal is collected by the output port of the winding equipment into the polarization maintaining coupler, and the polarization maintaining coupler divides the light wave into two beams which are transmitted to the optical power meter and the extinction ratio instrument respectively.

[0017] Further, the polarization maintaining coupler is a 1x2 polarization maintaining coupler.

[0018] Further, the method for real-time waveform analysis of the outgoing signal to realize non-destructive winding monitoring is to measure the transmission loss and extinction ratio of the optical power meter and the extinction ratio instrument, and the measurement results are sent to the upper computer for data analysis in real time, and the transmission loss and extinction ratio waveform changes are observed to monitor whether there is a phenomenon of deterioration of the light guiding quality of the hollow optical fiber during the winding process.

[0019] Further, the waveform change includes sudden signal and step signal.

[0020] A kind of hollow microstructure optical fiber ring nondestructive winding monitoring system,

[0021] The system includes polarization maintaining broadband light source, double-channel fiber rotary connector, fiber collimator, first mirror, second mirror, 1x2 polarization maintaining coupler, optical power meter, extinction ratio instrument, host computer and winding equipment,

[0022] High extinction ratio light wave emitted by polarization maintaining broadband light source is transmitted to the input port of the stator end of double-channel fiber rotary connector, the light wave is emitted from the output port of the rotor end of double-channel fiber rotary connector and coupled into all hollow microstructure optical fibers of the winding equipment, and then the parallel light beam is formed by the fiber collimator, the transmission direction of the light wave is adjusted by the first mirror and the second mirror, and then the light wave is coupled into the input port of the rotor end of the fiber rotary connector, and then the light wave is emitted from the output port of the stator end of the fiber rotary connector and enters the 1x2 polarization maintaining coupler, and the polarization maintaining coupler divides the light wave into two beams, which are transmitted to the optical power meter and the extinction ratio instrument for transmission loss and extinction ratio measurement, and the measurement results are transmitted to the host computer for data analysis in real time.

[0023] Further, the winding equipment includes a first fiber supply wheel, a second fiber supply wheel and a ring winding skeleton connected through the main shaft of the winding equipment,

[0024] The light wave emitted from the output port of the rotor end of the double-channel fiber rotary connector and coupled into the hollow microstructure optical fiber tail fiber of the first fiber supply wheel, and the light wave sequentially passes through the ring winding skeleton and the second fiber supply wheel.

[0025] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0026] 1. The hollow microstructure optical fiber ring online detection loop light wave is conducted regardless of the rotation of the ring winding equipment, has the ability of real-time optical fiber key optical index detection during online winding, can realize synchronous light guiding performance measurement and analysis during ring winding, helps to repair the negative effects of winding defects on hollow optical fiber light guiding quality in time, and achieves the effect of nondestructive winding of hollow microstructure optical fiber into a ring.

[0027] 2. During the winding process of the hollow microstructure optical fiber ring, the key performance of the hollow optical fiber light guiding is monitored in real time, which is beneficial to the accurate positioning of the hollow microstructure optical fiber ring winding process problem, and has the effect that the previous winding and detection method cannot achieve (for example, the current winding process problem can be solved immediately, without the need to adjust after the winding is completed, thereby reducing the waste of resources).

[0028] Additional aspects and advantages of the application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0030] FIG. 1 is a schematic diagram of a hollow microstructure optical fiber structure according to an embodiment of the application.

[0031] FIG. 2 is a schematic diagram of a hollow microstructure optical fiber loop lossless winding monitoring system structure according to an embodiment of the application.

[0032] In the figure: 1. Polarization maintaining broadband light source; 2. Double-channel optical fiber rotary connector; 3. First fiber supply wheel; 4. Winding equipment main shaft; 5. Loop winding framework; 6. Second fiber supply wheel; 7. Optical fiber collimator; 8. First mirror; 9. Second mirror; 10. 1x2 polarization maintaining coupler; 11. Optical power meter; 12. Extinction ratio instrument; 13. Upper computer. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the application more clear, the technical solutions in the application will be described clearly and completely in the following with reference to the drawings in the application. Obviously, the described embodiments are some embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the application. The following embodiments are used to illustrate the application, but cannot be used to limit the scope of the application.

[0034] In the description of the embodiments of the application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the embodiments of the application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the application. In addition, the terms "first", "second", "third" are only used for description purposes, and cannot be understood as indicating or implying relative importance.

[0035] In the description of the embodiments of the present application, it should be noted that unless specifically defined and limited otherwise, the terms "connected", "connected to", "connection" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0036] In the embodiments of the present application, unless otherwise specifically defined and limited, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0037] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0038] A method and system for monitoring the lossless winding of a hollow microstructure optical fiber ring are described below in connection with FIG. 1 and FIG. 2.

[0039] The application is directed to the problem of the decline of key optical indicators of the hollow microstructure optical fiber during the winding process of the hollow microstructure optical fiber into a ring, and proposes a lossless winding monitoring method and system configuration for the hollow microstructure optical fiber ring. A double-channel optical fiber rotary connector is arranged in the axial direction of the ring winding spindle, wherein one channel at the rotor end of the double-channel optical fiber rotary connector is connected with the optical fiber tail of the unspooled fiber supply reel rotating with the winding spindle, and the unspooled fiber supply reel and the rotor end of the optical fiber rotary connector rotate synchronously when the ring winding spindle rotates, and the optical connection between the two is always in a light waveguide state, regardless of the rotation of the ring winding spindle. The other channel at the rotor end of the double-channel optical fiber rotary connector is connected with the tail of the fiber supply reel in the rotating spooling process through two mirrors, and the tail port is in the direction of the rotating spindle of the fiber supply reel. When the ring winding spindle and the fiber supply reel in the spooling process rotate synchronously, the optical connection between the two is always in a light waveguide state, regardless of the rotation of the ring winding spindle and the fiber supply reel in the spooling process. At the same time, the two channels at the stator end of the optical fiber rotary connector are connected with the light source and the optical indicator detection instrument, respectively, and the optical connection is also independent of the rotation of the ring winding equipment. During the ring winding process using the symmetrical winding method, the light wave emitted by the light source can always return to the detection instrument (optical indicator detection instrument) through the hollow microstructure optical fiber to be wound, and the optical key performance can be monitored online and in real time during the winding process, which can support the lossless winding of the hollow microstructure optical fiber into a ring.

[0040] Figure 1 is a schematic diagram of a hollow microstructure optical fiber structure. The hollow microstructure optical fiber is an air hole that penetrates the entire optical fiber along the axial direction, with the end face periodic structure arranged on a single dielectric material (usually pure silica material). It uses several cladding microstructure units. In the legend, the cladding microstructure unit is a single circular tube, and the number is six, to construct the anti-resonance reflection effect to efficiently confine the light wave in the air core for transmission. Each cladding microstructure unit in the hollow optical fiber is connected to the circular tube type optical fiber cladding main structure at equal intervals, and the space surrounded by the six cladding microstructure units forms a negative curvature core (at the center of the optical fiber end face) for air light guiding. By controlling the difference in glass wall thickness of the single circular tube cladding microstructure in two orthogonal directions at the negative curvature core, the mode anti-cross coupling effect can be excited, high birefringence can be achieved, and the polarization maintaining light transmission effect of the hollow microstructure optical fiber can be formed.

[0041] Figure 2 is a hollow microstructure optical fiber coil nondestructive winding monitoring system, which mainly consists of a polarization maintaining broadband light source 1, a double-channel optical fiber rotary connector 2, a fiber collimator 7, a first mirror 8, a second mirror 9, a 1x2 polarization maintaining coupler 10, an optical power meter 11, an extinction ratio instrument 12, a host computer 13 and a winding device. The winding device consists of a fiber supply wheel, a winding device main shaft 4 and a coil winding skeleton 5, which has the function of symmetrically winding the optical fiber coil, i.e. the optical fiber to be wound is equally divided into two fiber supply wheels, the optical fiber is wound from the midpoint, and the two fiber supply wheels are sequentially wound onto the coil skeleton in a specific order according to the symmetric winding method (such as the four-pole winding method, etc.), the first fiber supply wheel 3 is selected for fiber unwinding and winding operation, and the second fiber supply wheel 6 rotates with the winding device main shaft, and the working positions of the two fiber supply wheels are alternated until the coil winding is completed.

[0042] In the hollow microstructure optical fiber coil nondestructive winding monitoring system, the high-extinction-ratio light wave emitted by the polarization maintaining broadband light source 1 is transmitted to the input port of the stator end of the double-channel optical fiber rotary connector 2, the light wave is emitted from the output port of the rotor end of the double-channel optical fiber rotary connector 2 and coupled into the hollow microstructure optical fiber tail fiber of the first fiber supply wheel 3, the light wave sequentially passes through all the hollow microstructure optical fibers on the coil winding skeleton and the second fiber supply wheel 6, and then forms a parallel light beam after being emitted by the fiber collimator 7, and then the transmission direction of the light wave is adjusted by the first mirror 8 and the second mirror 9, and then coupled into the input port of the rotor end of the optical fiber rotary connector, and then emitted from the output port of the stator end of the optical fiber rotary connector into the 1x2 polarization maintaining coupler 10. The polarization maintaining coupler divides the light wave into two beams which are transmitted to the optical power meter 11 and the extinction ratio instrument 12 for transmission loss and extinction ratio measurement, and the measurement results are sent to the host computer for data analysis in real time to monitor whether there is a phenomenon of deterioration of the light guiding quality of the hollow optical fiber during the winding process. When the above-mentioned key optical indicators (such as including transmission loss and extinction ratio) are affected by the winding and deteriorate, an alarm signal is sent out to adjust the winding tension and torsion process parameters, so as to support the realization of nondestructive winding of the hollow microstructure optical fiber coil. In this embodiment, the phenomenon of deterioration of the light guiding quality of the hollow optical fiber is determined by observing the waveform changes of the transmission loss and the extinction ratio, such as sudden change, step change, etc., which can be used as a judgment.

[0043] In another embodiment, the double-channel optical fiber rotary connector is installed on the rotating shaft of the winding device main shaft, the rotor end of the double-channel optical fiber rotary connector is fixedly connected with the winding device main shaft and rotates synchronously with the winding device main shaft, and the stator end of the double-channel optical fiber rotary connector is mechanically fixed without rotating.

[0044] In another embodiment, the first fiber supply wheel is fixed on the winding device main shaft, and the output port of the rotor end of the optical fiber rotary connector emits light waves to be coupled into the tail fiber of the first fiber supply wheel. When the winding device main shaft rotates, the first fiber supply wheel and the rotor end of the optical fiber rotary connector rotate synchronously. The optical connection between the tail fiber of the first fiber supply wheel and the rotor end of the optical fiber rotary connector is always in a light wave conducting state, regardless of the rotation of the winding device main shaft.

[0045] In another embodiment, the hollow-core microstructured fiber tail fiber collimator of the second fiber supply wheel is fixed on the rotation axis of the second fiber supply wheel. The parallel light beams emitted by the hollow-core microstructured fiber tail fiber collimator of the second fiber supply wheel are spatially coupled into the input port of the rotor end of the optical fiber rotary connector after passing through two mirrors. When the winding device main shaft and the second fiber supply wheel rotate synchronously, the optical connection between the hollow-core microstructured fiber tail fiber collimator of the second fiber supply wheel and the rotor end of the optical fiber rotary connector is always in a light wave conducting state, regardless of the rotation of the winding device main shaft and the second fiber supply wheel.

[0046] In another embodiment, the first fiber supply wheel and the second fiber supply wheel are sequentially exchanged in working position according to the symmetrical winding method of the fiber coil.

[0047] In another embodiment, the type of optical index detection instrument in the system can be adjusted and replaced according to the degree of attention to the light guiding characteristics of the hollow-core microstructured fiber, such as a spectrometer, a polarization degree instrument, and a mode field analyzer.

[0048] In summary, the present application proposes a hollow-core microstructured fiber coil lossless winding monitoring method and system configuration based on a double-channel optical fiber rotary connector, which can solve the problem of deterioration of fiber light guiding quality during the winding of hollow-core microstructured fiber into a ring, and achieve the effect of lossless winding of hollow-core microstructured fiber into a ring. The method and system configuration are suitable for any type of lossless winding operation of hollow-core microstructured fiber into a ring, such as hollow-core anti-resonant fiber and hollow-core photonic bandgap fiber.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some technical features. Such modifications or substitutions do not change the essence of the corresponding technical solutions, and are within the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of non-destructive monitoring of the winding of a hollow core microstructured fiber loop, characterized in that, It comprises the following steps: Symmetrically winding the hollow microstructure optical fiber by winding equipment; High-extinction-ratio light wave is incident on the winding equipment, and the outgoing signal is collected at the outgoing port; And Real-time waveform analysis of the outgoing signal during winding to realize non-destructive winding monitoring.

2. The non-destructive winding monitoring method of the hollow microstructure optical fiber coil according to claim 1, wherein the symmetric winding is sequentially winding the two fiber supply wheels onto the coil skeleton, the first fiber supply wheel performs fiber winding operation, the second fiber supply wheel rotates with the main shaft of the winding equipment, and the working positions of the two fiber supply wheels are alternately changed until the winding of the coil is completed.

3. The non-destructive winding monitoring method of the hollow microstructure optical fiber coil according to claim 1, wherein the symmetric winding method is four-pole winding.

4. The non-destructive winding monitoring method of the hollow microstructure optical fiber coil according to claim 1, wherein the method of incident high-extinction-ratio light wave on the winding equipment is: The high-extinction-ratio light wave emitted by the polarization-maintaining broadband light source is transmitted to the input port of the double-channel fiber rotary connector stator end, and the high-extinction-ratio light wave is emitted at the output port of the double-channel fiber rotary connector rotor end and coupled into the winding equipment.

5. The non-destructive winding monitoring method of the hollow microstructure optical fiber coil according to claim 1, wherein the collection of the outgoing signal at the outgoing port is that the light wave emitted by the output port of the winding equipment enters the polarization-maintaining coupler, and the polarization-maintaining coupler divides the light wave into two beams which are transmitted to the optical power meter and the extinction ratio instrument respectively.

6. The non-destructive winding monitoring method of the hollow microstructure optical fiber coil according to claim 5, wherein the polarization-maintaining coupler is a 1×2 polarization-maintaining coupler.

7. The non-destructive winding monitoring method of the hollow microstructure optical fiber coil according to claim 5, wherein the real-time waveform analysis of the outgoing signal to realize non-destructive winding monitoring is that the transmission loss and extinction ratio of the optical power meter and the extinction ratio instrument are measured, the measurement results are sent to the upper computer for data analysis in real time, and the transmission loss and extinction ratio waveform changes are observed to monitor whether there is a phenomenon of deterioration of the light guiding quality of the hollow optical fiber in the winding process.

8. The non-destructive winding monitoring method of the hollow microstructure optical fiber coil according to claim 7, wherein the waveform changes include sudden signal and step signal.

9. A non-destructive winding monitoring system for a hollow microstructure optical fiber coil, comprising a polarization-maintaining broadband light source, a double-channel fiber rotary connector, a fiber collimator, a first mirror, a second mirror, a 1×2 polarization-maintaining coupler, an optical power meter, an extinction ratio instrument, an upper computer, and winding equipment. ​ ​ ​ ​ ​ ​ ​ ​ The high-extinction-ratio light wave emitted by the polarization maintaining broadband light source is transmitted to the input port of the double-channel fiber rotary connector stator end, the light wave is emitted from the output port of the double-channel fiber rotary connector rotor end and coupled into all the hollow microstructure optical fibers of the winding device, then forms a parallel light beam by the optical fiber collimator, adjusts the light wave transmission direction by the first and second mirrors, and is coupled into the input port of the fiber rotary connector rotor end, and is emitted from the output port of the fiber rotary connector stator end into the 1x2 polarization maintaining coupler, the polarization maintaining coupler equally divides the light wave into two beams which are transmitted to the optical power meter and the extinction ratio instrument respectively to measure the transmission loss and the extinction ratio and obtain the measurement results, and the measurement results are transmitted to the upper computer in real time for data analysis.

10. A hollow-core microstructured optical fibre loop lossless spooling monitoring system according to claim 9, wherein, The winding device comprises a first fiber supply wheel, a second fiber supply wheel and a loop winding framework connected on the main shaft of the winding device, Wherein, the light wave emitted from the output port of the double-channel fiber rotary connector rotor end and coupled into the hollow microstructure optical fiber tail fiber of the first fiber supply wheel is transmitted, and the light wave sequentially passes through the loop winding framework and the second fiber supply wheel.

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