A manufacturing method of a decoherence optical fiber

Abstract

The present invention relates to the field of optical fiber technology, and particularly to a method for manufacturing a decoherence optical fiber. The present invention discloses a method for manufacturing a decoherence optical fiber, which includes the following steps: S1, take a conventional optical fiber, the core of which is a cylindrical structure; S2, randomly twist the conventional optical fiber along its axis in units of a certain length, and the twisting is performed with the core axis of the core as the self-rotation axis. The optical fiber structure manufactured by the present invention can disrupt the coherence of the transmitted light to achieve the output of broadband flat light, meet the requirements of optical fiber gyroscopes and the like for broadband light sources, and has a simple manufacturing process, is easy to implement, and has a low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fibers, and particularly relates to a method for manufacturing a de-coherent optical fiber. Background Art

[0002] Broad-spectrum flat light refers to a light beam with uniform light intensity distribution within a broad spectrum in the laser transmission direction. Due to the uniform energy distribution, it is widely used in fine processing fields such as fiber optic gyroscopes, fiber optic sensing systems, fiber optic passive device testing, wavelength division multiplexing device testing, and EDFA testing. Because broad-spectrum flat light has the characteristics of a broad spectrum, stable power, and uniform energy distribution, it can meet the requirements of the light source for fiber optic gyroscopes and is the main light source for gyroscopes.

[0003] Currently, there are mainly two types of flat-top light sources used in fiber optic gyroscopes: spontaneous emission amplified radiation light sources (ASE) and superluminescent diode light sources (SLD). Among them, the ASE light source is the mainstream. It can operate in the entire C+L band, with a range of 1530nm - 1605nm, and has excellent broad-spectrum characteristics. In addition, because the internal coherence of the ASE light source is weaker than that of the SLD, the spectral distribution is closer to a rectangle (while the distribution of the SLD is Gaussian-like), and it has better application effects in fiber optic gyroscopes. Finally, the ASE light source is relatively easy to achieve a large output power through an external control circuit, with a wider application range and stronger practicability.

[0004] At the same time, due to the relatively wide working spectrum of the ASE light source, the spectral flatness of its full bandwidth is not yet ideal. The flatness is mainly restricted by the coherence degree during the light emission process of the light source. Reducing the coherence degree between photons can correspondingly improve the flatness of the output light field or the stability of the light intensity.

[0005] It is found in experiments that when laser transmits in an optical fiber, by performing corresponding processing on the optical fiber, the coherence of the laser can be greatly eliminated, thereby improving the spectral flatness. The existing method for processing the optical fiber is to change the working environment of the optical fiber through an infiltration method to de-cohere, but this method has a complex process, is not easy to implement, and does not meet the requirements of the fiber optic gyroscope device for the light source, so it has not been applied. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for manufacturing a de-coherent optical fiber to solve the above-mentioned existing technical problems.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is: a method for manufacturing a de-coherent optical fiber, including the following steps:

[0008] S1, take a conventional optical fiber, and the core of the conventional optical fiber is a cylindrical structure;

[0009] S2. Randomly twist the conventional optical fiber along its axis in units of a certain length, and the twisting is carried out with the core axis of the fiber core as the self-rotation axis.

[0010] Furthermore, in step S2, before performing the random twisting, heat the part to be twisted to make the fiber core reach the soft point.

[0011] Furthermore, in step S2, the random twisting includes random twisting direction and random twisting angle.

[0012] Furthermore, in step S2, the unit length is 1 cm, and the twisting angle is between 10 and 60 degrees.

[0013] Furthermore, the fiber core is made of glass material or plastic material.

[0014] Furthermore, it further includes step S3. Take a support wire, and helically wind the optical fiber processed in step S2 around the support wire, and the pitch along the winding direction is randomly distributed.

[0015] Even further, the support wire is an elastic cord.

[0016] Furthermore, the diameter of the support wire is 2 - 10 mm.

[0017] Furthermore, the pitch is 2 - 15 mm.

[0018] Furthermore, it further includes step S4. Use a fixing member to fix the optical fiber on the support wire.

[0019] Advantageous technical effects of the present invention:

[0020] The optical fiber structure made by the present invention can well disrupt the coherence of the transmitted light to achieve the output of wide-spectrum flat light, meet the requirements for broadband light sources such as fiber optic gyroscopes, and has a simple manufacturing process, is easy to implement, and has a low cost. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is the flowchart of the method of the specific embodiment of the present invention;

[0023] Figure 2 It is the schematic diagram of the fiber core structure before performing random twisting in the specific embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the fiber core structure after being processed through step S2 in a specific embodiment of the present invention;

[0025] Figure 4 Structural diagram of the optical fiber structure fabricated in a specific embodiment of the present invention;

[0026] Figure 5 Polarization state diagram of the polarized light of a laser pen passing through a conventional optical fiber;

[0027] Figure 6a and 6b Polarization state diagrams of the polarized light of a laser pen passing through the optical fiber structure fabricated by the present invention at different moments. Specific embodiments

[0028] To further illustrate the embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, mainly used to illustrate the embodiments, and can be combined with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, those of ordinary skill in the art should be able to understand other possible embodiments and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0030] As Figure 1 shown, a method for fabricating a decoherence optical fiber includes the following steps:

[0031] S1, take a conventional optical fiber, the fiber core of which is a cylindrical structure.

[0032] The conventional optical fiber mentioned here refers to the ordinary optical fiber available on the market, including an outer cladding and a cylindrical fiber core 11 (as Figure 2 shown) wrapped inside the outer cladding. The fiber core 11 can be a glass fiber core, a plastic fiber core, etc. At the same time, the fiber core 11 can be a single-mode fiber core or a multi-mode fiber core.

[0033] S2, randomly twist the conventional optical fiber along its axial direction in units of a certain length. The twisting is performed with the core axis of the fiber core 11 as the self-rotation axis.

[0034] Random twisting means that the twisting of each unit is different and does not form a periodic structure. For example, the first unit is twisted clockwise by 40 degrees, the second unit is twisted clockwise by 45 degrees, the third unit is twisted clockwise by 30 degrees, the fourth unit is twisted counterclockwise by 40 degrees..., and the twisting is irregular. Through random twisting, different and irregular (random) stress surfaces are generated on the fiber core axial plane, disrupting the coherence of the transmitted light to achieve the output of broadband flat light.

[0035] Further, in this embodiment, before performing random twisting, the portion to be twisted is heated to make the core 11 reach the soft point, which is convenient for twisting deformation and not easy to break the core 11. Heating can be achieved by using various existing heating devices, such as using an electric heater for heating.

[0036] Specifically, in this embodiment, first, the portion of the optical fiber to be twisted is heated to make the core 11 reach the soft point, and then after clamping both ends of the portion to be twisted with a bayonet, one of the buckles is rotated to drive the core 11 to twist.

[0037] Preferably, in this specific embodiment, the random twisting includes random twisting direction and random twisting angle, which makes the decoherence better, but is not limited to this.

[0038] Preferably, in this specific embodiment, the unit length is 1 centimeter, but is not limited to this. The twisting angle of the core 11 per 1 centimeter length along its axial direction is between 10 - 60 degrees, which can not only ensure the function of changing coherence but also prevent the core 11 from breaking and affecting its light transmission.

[0039] Figure 2 Shown is the structure of the core 11' after being processed by step S2.

[0040] Further, in this embodiment, it further includes step S3. Take a support wire 2 and helically wind the optical fiber 1 processed by step S2 around the support wire 2, and the pitch along the winding direction is randomly distributed, as Figure 3 shown.

[0041] The random distribution of the pitch means that along the winding direction, the sizes of the pitches are different and do not have periodicity, that is, they are irregularly distributed. Further, by randomly bending the core axial plane, different stress planes are generated to more thoroughly disrupt the coherence of the transmitted light to achieve the output of wide - spectrum flat light.

[0042] Preferably, in this embodiment, the support wire 2 is cylindrical, which is easy to implement and makes the curvature of the helically wound optical fiber 1 relatively gentle, and will not break the core 11' and affect its light transmission. However, it is not limited to this. In some embodiments, the support wire 2 can also be prismatic, etc.

[0043] Preferably, in this embodiment, the support wire 2 is soft and can be bent to a certain extent for easy use. However, it is not limited to this. In some embodiments, the support wire 2 can also be a rigid support wire.

[0044] In this specific embodiment, the support wire 2 is an elastic cord, which has good toughness and low cost. However, it is not limited to this. In other embodiments, the support wire 2 can also be made of other materials such as plastic and metal.

[0045] Preferably, in this specific embodiment, the diameter of the support wire 2 is 2-10 mm, which can not only ensure the effect of influencing polarization, but also does not affect its light transmittance and will not break the core 11' of the optical fiber 1.

[0046] Preferably, in this specific embodiment, the pitch is 2-15 mm, which can not only ensure a better effect of influencing polarization, but also does not affect its light transmittance.

[0047] Furthermore, in this embodiment, it further includes step S4 of fixing the optical fiber 1 on the support wire 2 by a fixing member to prevent the optical fiber 1 from moving and deforming.

[0048] In this embodiment, the optical fiber 1 is fixed on the support wire 2 by epoxy resin, which is easy to implement and has a low cost. However, it is not limited to this. In other embodiments, a loose tube or a heat shrink tube can also be used for wrapping and fixing.

[0049] After fixing, both ends 12 and 13 of the optical fiber 1 are left as optical fiber interfaces for convenient and flexible disassembly.

[0050] Experimental verification:

[0051] Taking a laser pen as the light source, after passing through an ordinary optical fiber and the optical fiber structure made by the present invention, the polarization property is tested. Since the laser pen is linearly polarized light, after passing through an ordinary optical fiber, the polarization direction deflects by a certain angle, but it is still linearly polarized light, as Figure 5 shown; after passing through the optical fiber structure made by the present invention, the polarization direction is completely random, and the polarization state also changes, and linearly polarized light (such as Figure 6a ) and elliptically polarized light (such as Figure 6b ) will be randomly output. That is, the optical fiber structure made by the present invention can well disrupt the coherence of the transmitted light to achieve the output of wide-spectrum flat light, meet the requirements of fiber optic gyroscopes and other devices for broadband light sources, and has a simple manufacturing process, is easy to implement, and has a low cost.

[0052] Although the present invention is specifically shown and described in combination with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present invention in form and details without departing from the spirit and scope of the present invention defined by the appended claims, and all of them are within the protection scope of the present invention.

Claims

1. A manufacturing method of a decoherence optical fiber, characterized in that, It includes the following steps: S1. Take a conventional optical fiber, the core of which is a cylindrical structure; S2. Randomly twist the conventional optical fiber along its axis in units of a certain length, and the twisting is carried out with the core axis of the core as the self-rotation axis; In step S2, the random twisting includes random twisting direction and random twisting angle; the unit length is 1 cm, and the twisting angle is between 10° and 60°.

2. The manufacturing method of the decoherence optical fiber according to claim 1, wherein: In step S2, before the random twisting, heat the part to be twisted to make the core reach the soft point.

3. The manufacturing method of the decoherence optical fiber according to claim 1, characterized in that: The core is made of glass material or plastic material.

4. The manufacturing method of the decoherence optical fiber according to any one of claims 1-3, characterized in that: It further includes step S3. Take a support wire, and helically wind the optical fiber processed in step S2 on the support wire, and the pitch along the winding direction is randomly distributed.

5. The manufacturing method of the decoherence optical fiber according to claim 4, characterized in that: The support wire is an elastic cord.

6. The manufacturing method of the decoherence optical fiber according to claim 5, wherein: The diameter of the support wire is 2 - 10 mm.

7. The manufacturing method of the decoherence optical fiber according to claim 4, characterized in that: The pitch is 2 - 15 mm.

8. The manufacturing method of the decoherence optical fiber according to claim 4, characterized in that: It further includes step S4. Fix the optical fiber on the support wire with a fixing piece.

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