High-power optical fiber transmission jumper wire and manufacturing method thereof

Abstract

The invention discloses a high-power optical fiber transmission jumper wire and a manufacturing method thereof, and the jumper wire comprises a fiber core which is made of a non-doped quartz material; the wrapping layer wraps the outer side of the fiber core; the end structures are arranged at the two ends of the fiber core; the joint is connected to the end part of the fiber core, the joint comprises an inner ring, and the inner diameter of the inner ring is in interference fit with the outer diameter of the fiber core; the outer shell is made of titanium alloy, the outer shell is fixedly connected with the inner ring, and the outer shell is provided with a fluid connector communicated with the cooling channel. Through cooperative use of the non-doped porous quartz fiber core and the magnesium fluoride aerogel cladding, the nonlinear effect and heat accumulation of the fiber core are effectively reduced, the problem that the transmission efficiency of an existing ytterbium-doped photonic crystal fiber is reduced due to the fact that a thermally induced mode is unstable under high power is solved, the laser damage threshold of an optical fiber patch cord is increased, and the optical fiber patch cord is suitable for large-scale popularization and application. And meanwhile, the cost problem of relying on imported materials is avoided.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber transmission, in particular to a high-power optical fiber transmission jumper and a manufacturing method thereof. Background Art

[0002] High-power fiber optic patch cords are key transmission components between laser equipment and processing systems, and are widely used in industrial manufacturing (such as metal cutting and welding), medical laser equipment, space laser communications, and other fields. With the continuous increase in laser power (such as 10kW and above), traditional fiber optic patch cords face severe challenges in terms of heat dissipation performance, damage threshold, and environmental adaptability. Especially in industrial laser processing, high-power lasers (>500W / mm 2 ) Long-term operation will lead to problems such as excessive temperature rise of the optical fiber end face and coating shedding, which will seriously affect the processing accuracy and equipment life.

[0003] Currently, high-power fiber patch cables primarily utilize ytterbium-doped photonic crystal fibers (PCFs) with end-face low-reflection coatings (LR coatings). However, the preparation of ytterbium-doped fibers relies on complex crystal growth processes, and the efficiency of ytterbium atoms' pump energy level transitions is significantly affected by temperature. This leads to thermally induced mode instability (TMI) during prolonged high-power operation, resulting in decreased laser transmission efficiency and fiber core damage. Furthermore, this technology relies on imported fiber materials, resulting in high costs and difficulty meeting the needs of large-scale industrial applications. Summary of the Invention

[0004] The object of the present invention is to provide a high-power optical fiber transmission jumper and a manufacturing method thereof, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A high-power optical fiber transmission jumper, comprising

[0007] The fiber core is made of undoped quartz material, and a periodic array of air holes extending along the axial direction is provided inside the fiber core. The aperture of the air holes is 50nm to 100nm, and the spacing between adjacent air holes is 8μm to 12μm;

[0008] a cladding, covering the outside of the fiber core;

[0009] end structures, arranged at both ends of the fiber core;

[0010] A connector connected to the end of the fiber core, the connector comprising an inner ring made of porous silicon carbide, the inner diameter of the inner ring being interference fit with the outer diameter of the fiber core, the interference being 0.3 μm to 0.7 μm;

[0011] The outer shell is made of titanium alloy, is fixedly connected to the inner ring, and is provided with a fluid interface communicating with the cooling channel.

[0012] In the present invention, the cladding comprises

[0013] An inner cladding layer is composed of magnesium fluoride aerogel, wherein the refractive index of the magnesium fluoride aerogel is less than or equal to 0.35;

[0014] The outer layer is a metal tube body, the inner wall of which is provided with a spiral cooling channel. The cross section of the cooling channel is semicircular and the width is 0.4mm to 0.6mm. The cooling medium flowing in the spiral cooling channel is argon or deionized water.

[0015] In the present invention, the end structure includes

[0016] The end face is a convex micro-lens structure, and the curvature radius of the convex micro-lens is 4mm to 6mm;

[0017] An optical film is coated on the end face, wherein the optical film is composed of alternately stacked silicon nitride layers and hafnium dioxide layers, the total number of layers of the optical film is 5 to 9, the thickness of the silicon nitride layer is 20 nm to 50 nm, and the thickness of the hafnium dioxide layer is 5 nm to 30 nm.

[0018] In the present invention, the outer shell is fixedly connected to the inner ring by laser welding, and the welding power is 100W to 200W.

[0019] A method for manufacturing a high-power optical fiber transmission jumper includes the following steps:

[0020] Step S1, fiber core preparation, forming the air hole array in a quartz substrate using a chemical vapor deposition process;

[0021] Step S2, cladding assembly, forming the magnesium fluoride aerogel inner cladding on the outer side of the fiber core by a sol-gel method, sleeved a metal tube pre-machined with the cooling channel on the outer side of the inner cladding, and sealed by laser welding;

[0022] Step S3, end face processing, using a femtosecond laser with a pulse energy of 8 μJ to 12 μJ to process the convex microlens structure on the end face of the fiber core, and using an ion beam to polish the end face to make the surface roughness Ra ≤ 0.5 nm;

[0023] Step S4, coating treatment, alternately depositing the silicon nitride layer and the hafnium dioxide layer on the end surface by an atomic layer deposition process;

[0024] Step S5: assembling the connector, interference-fitting the fiber core end with the inner ring, and fixing the outer shell by laser welding.

[0025] In the present invention, in step S4, the reaction temperature of the atomic layer deposition process is 20° C. to 30° C., and the reaction pressure is 0.1 Pa to 1 Pa.

[0026] The present invention also includes placing the optical fiber jumper at a power density of 400W / mm 2 ~600W / mm 2 When the laser is continuously operated for 0.5h to 2h in a laser environment, the temperature rise of the detection end face is ≤15℃.

[0027] In the present invention, in step S2, the scanning speed of the laser welding is 5 mm / s to 10 mm / s.

[0028] In the present invention, in step S3, the repetition frequency of the femtosecond laser is 80 kHz to 120 kHz.

[0029] A laser transmission system comprising

[0030] The high-power optical fiber transmission jumper;

[0031] a cooling device connected to the fluid interface;

[0032] A laser is optically coupled to the fiber optic patch cable.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention effectively reduces the nonlinear effect and heat accumulation of the fiber core by using a non-doped porous quartz fiber core in combination with a magnesium fluoride aerogel cladding, solving the problem of decreased transmission efficiency caused by thermally induced mode instability at high power in existing ytterbium-doped photonic crystal fibers. It also improves the laser damage threshold of fiber jumpers while avoiding the cost of relying on imported materials.

[0035] 2. The present invention achieves efficient heat dissipation and thermal stress self-compensation through the synergistic effect of the spiral microchannel cooling structure and the gradient refractive index optical film, solving the problem of film cracking caused by thermal expansion coefficient mismatch in traditional coatings. After the laser continues to work, the fiber core temperature rises, significantly improving the long-term reliability of the optical fiber in high temperature and high vibration environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the optical fiber structure of a high-power optical fiber transmission jumper of the present invention;

[0037] Figure 2 This is a schematic diagram of the working process of a high-power optical fiber transmission jumper of the present invention;

[0038] Figure 3 This is a schematic diagram of the working process of a cooling system for a high-power optical fiber transmission jumper of the present invention;

[0039] Figure 4 The present invention is a schematic diagram of a performance test process of a high-power optical fiber transmission jumper. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] Example 1

[0042] like Figure 1 As shown, a high-power optical fiber transmission jumper includes

[0043] The fiber core is made of undoped quartz material, and a periodic array of air holes extending along the axial direction is provided inside the fiber core. The aperture of the air holes is 50nm to 100nm, and the spacing between adjacent air holes is 8μm to 12μm;

[0044] A cladding layer is coated on the outside of the core, and the cladding layer includes

[0045] An inner cladding layer is composed of magnesium fluoride aerogel, wherein the refractive index of the magnesium fluoride aerogel is ≤ 0.35, wherein the low refractive index (<1.38) of the magnesium fluoride aerogel ensures an optical waveguide effect, while the porous structure (porosity > 90%) provides excellent thermal insulation performance;

[0046] The outer layer is a metal tube body, the inner wall of the metal tube body is provided with a spiral cooling channel, the spiral angle is 45 degrees to ensure sufficient heat exchange, the cross section of the cooling channel is semicircular, the width is 0.4mm to 0.6mm, and the cooling medium flowing in the spiral cooling channel is argon gas or deionized water;

[0047] End structures are provided at both ends of the fiber core, and the end structures include

[0048] The end face is a convex micro-lens structure, and the curvature radius of the convex micro-lens is 4mm to 6mm;

[0049] An optical film coated on the end face, the optical film being composed of alternating silicon nitride layers and hafnium dioxide layers, the total number of layers of the optical film being 5 to 9, the thickness of the silicon nitride layer being 20 nm to 50 nm, and the thickness of the hafnium dioxide layer being 5 nm to 30 nm, wherein the thermal expansion coefficients of the silicon nitride layer and the hafnium dioxide layer are 3.2 and 5.5 × 10^-6 / °C, respectively, forming a gradient compensation with quartz (0.55 × 10^-6 / °C);

[0050] A connector is connected to the end of the fiber core, the connector including an inner ring made of porous silicon carbide, the inner diameter of the inner ring having an interference fit with the outer diameter of the fiber core, the interference fit being 0.3 μm to 0.7 μm. The interference fit of the connector in the range of 0.3-0.7 μm ensures sealing and avoids excessive stress on the fiber core;

[0051] The outer shell is made of titanium alloy and is fixedly connected to the inner ring by laser welding with a welding power of 100W to 200W. The outer shell is provided with a fluid interface communicating with the cooling channel.

[0052] In this embodiment, the non-doped porous silica core and the magnesium fluoride aerogel cladding are used together to effectively reduce the nonlinear effect and heat accumulation of the core, and solve the problem of the existing ytterbium-doped photonic crystal fiber at high power (>500W / mm 2 ) due to the decrease in transmission efficiency caused by thermally induced mode instability (TMI), the laser damage threshold of the fiber jumper is increased to ≥500W / mm 2 , while avoiding the cost of relying on imported materials.

[0053] Furthermore, through the synergistic effect of the spiral microchannel cooling structure and the gradient refractive index optical film, efficient heat dissipation and thermal stress self-compensation are achieved, solving the film cracking problem caused by the mismatch of thermal expansion coefficients in traditional coatings. 2 After the laser works continuously for 1 hour, the fiber core temperature rise is ≤10℃, which significantly improves the long-term reliability of the optical fiber in high temperature and high vibration environments.

[0054] like Figure 2-3 As shown, a method for manufacturing a high-power optical fiber transmission jumper includes the following steps: Step S1, preparing the fiber core:

[0055] The fiber core preform is prepared using a modified chemical vapor deposition (MCVD) process. The specific steps are:

[0056] Step S101, selecting a quartz tube with a purity of ≥99.999% as a base material;

[0057] Step S102, during the deposition process, SiCl4 and O2 are introduced into the reaction chamber through a precisely controlled airflow system, and the deposition temperature is controlled at 1600±50°C;

[0058] Step S103 , using a 532 nm pulsed laser to drill holes in the deposited layer, with a laser power of 10 W, a pulse width of 100 ns, and a repetition frequency of 10 kHz, to form a periodic air hole array with an aperture of 80 ± 20 nm and a spacing of 10 ± 2 μm;

[0059] Step S104 , collapsing the preform into a solid optical fiber at 1800° C., with the final fiber core diameter being 300±50 μm.

[0060] Step S2, cladding assembly:

[0061] Step S201, inner cladding preparation:

[0062] A magnesium fluoride precursor solution (concentration of 0.5 mol / L) was coated on the core surface by an immersion method, gelled at 50°C for 24 hours, and then heat treated at 600°C for 2 hours to form a magnesium fluoride aerogel layer with a thickness of 100±20 μm. The refractive index was measured to be 0.34±0.01.

[0063] Step S202: outer cladding preparation:

[0064] A 316L stainless steel tube with an outer diameter of 2.0 mm and a wall thickness of 0.3 mm was selected. A spiral flow channel with a width of 0.5 ± 0.1 mm and a depth of 0.25 ± 0.05 mm, with a pitch of 5 mm, was machined into the inner wall of the tube using a precision CNC milling machine. The fiber core, coated with the inner cladding, was sealed within the stainless steel tube using laser welding at a power of 150 W and a speed of 8 mm / s.

[0065] Step S3, end surface processing:

[0066] Step S301: A femtosecond laser processing system (wavelength 1030 nm, pulse energy 10±2 μJ, repetition rate 100 kHz) is used to process a convex microlens with a curvature radius of 5±1 mm on the fiber core end face. The pulse energy of the femtosecond laser processing is less than 15 μJ to avoid the heat-affected zone, and greater than 5 μJ to ensure processing efficiency.

[0067] In step S302 , an argon ion beam polisher (accelerating voltage 500 V, beam current 50 mA) is used for polishing for 30 minutes, and the surface roughness Ra is measured to be 0.4±0.1 nm.

[0068] Step S4, coating treatment:

[0069] Using an atomic layer deposition system:

[0070] Step S401, depositing a silicon nitride layer: the precursors are SiH2Cl2 and NH3, the deposition temperature is 25±5°C, and the single layer thickness is 25±5nm;

[0071] Step S402, depositing a hafnium dioxide layer: the precursors are TEMAH and H2O, the deposition temperature is 25±5°C, and the single layer thickness is 15±5 nm;

[0072] In step S403 , 7 layers (4 layers of Si 3 N 4 and 3 layers of HfO 2 ) are alternately deposited, with a total thickness of about 145 nm.

[0073] Step S5, connector assembly:

[0074] Step S501, silicon carbide inner ring: porosity 30±5%, inner diameter 300±1 μm, interference fit with the fiber core 0.5±0.2 μm;

[0075] Step S501, titanium alloy shell: using Ti6Al4V powder, through selective laser melting (SLM) 3D printing, laser power 200W, scanning speed 1m / s;

[0076] Step S501, assembly: In a clean bench (Class 100), use a micron-level positioning device to press the fiber core into the silicon carbide ring, and then laser weld the titanium alloy shell with a welding power of 180 W and a welding speed of 6 mm / s.

[0077] Example 2

[0078] like Figure 4 As shown in the figure, the performance test of a high-power optical fiber transmission patch cord includes:

[0079] Optical performance test:

[0080] At a wavelength of 1080nm, the insertion loss is measured to be ≤0.3dB / m. Using pulsed laser (pulse width 10ns, repetition frequency 10kHz) for testing, the damage threshold is ≥500W / mm 2 .

[0081] Thermal performance test:

[0082] 25℃ deionized water (flow rate 1L / min) was introduced and the 2 After 1 hour of continuous laser irradiation, the maximum temperature of the fiber core is 35±2℃, and the temperature rise at the connector is 8±1℃;

[0083] After thermal cycling test (-40°C to 85°C, 100 cycles), the optical performance change was less than 1%.

[0084] Mechanical properties test:

[0085] No structural damage after vibration testing (20-2000Hz, 5g acceleration, 1 hour each on 3 axes);

[0086] Tensile test: can withstand axial tension ≥100N.

[0087] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0088] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high-power optical fiber transmission jumper, characterized by: include The fiber core is made of undoped quartz material, and a periodic array of air holes extending along the axial direction is provided inside the fiber core. The aperture of the air holes is 50nm to 100nm, and the spacing between adjacent air holes is 8μm to 12μm; a cladding, covering the outside of the fiber core; end structures, arranged at both ends of the fiber core; A connector connected to the end of the fiber core, the connector comprising an inner ring made of porous silicon carbide, the inner diameter of the inner ring being interference fit with the outer diameter of the fiber core, the interference being 0.3 μm to 0.7 μm; The outer shell is made of titanium alloy, is fixedly connected to the inner ring, and is provided with a fluid interface communicating with the cooling channel.

2. The high-power optical fiber transmission jumper according to claim 1, characterized in that: The cladding includes An inner cladding layer is composed of magnesium fluoride aerogel, wherein the refractive index of the magnesium fluoride aerogel is less than or equal to 0.35; The outer layer is a metal tube body, the inner wall of which is provided with a spiral cooling channel. The cross section of the cooling channel is semicircular and the width is 0.4mm to 0.6mm. The cooling medium flowing in the spiral cooling channel is argon or deionized water.

3. The high-power optical fiber transmission jumper according to claim 1, characterized in that: The end structure includes The end face is a convex micro-lens structure, and the curvature radius of the convex micro-lens is 4mm to 6mm; An optical film is coated on the end face, wherein the optical film is composed of alternately stacked silicon nitride layers and hafnium dioxide layers, the total number of layers of the optical film is 5 to 9, the thickness of the silicon nitride layer is 20 nm to 50 nm, and the thickness of the hafnium dioxide layer is 5 nm to 30 nm.

4. The high-power optical fiber transmission jumper according to claim 1, characterized in that: The outer shell is fixedly connected to the inner ring by laser welding, and the welding power is 100W to 200W.

5. A method for manufacturing a high-power optical fiber transmission jumper according to any one of claims 1 to 4, characterized in that: The following steps are included Step S1, fiber core preparation, forming the air hole array in a quartz substrate using a chemical vapor deposition process; Step S2, cladding assembly, forming the magnesium fluoride aerogel inner cladding on the outer side of the fiber core by a sol-gel method, sleeved a metal tube pre-machined with the cooling channel on the outer side of the inner cladding, and sealed by laser welding; Step S3, end face processing, using a femtosecond laser with a pulse energy of 8 μJ to 12 μJ to process the convex microlens structure on the end face of the fiber core, and using an ion beam to polish the end face to make the surface roughness Ra ≤ 0.5 nm; Step S4, coating treatment, alternately depositing the silicon nitride layer and the hafnium dioxide layer on the end surface by an atomic layer deposition process; Step S5: assembling the connector, interference-fitting the fiber core end with the inner ring, and fixing the outer shell by laser welding.

6. The production method according to claim 5, characterized in that: In step S4, the reaction temperature of the atomic layer deposition process is 20° C. to 30° C., and the reaction pressure is 0.1 Pa to 1 Pa.

7. The production method according to claim 5, characterized in that: The optical fiber jumper is placed at a power density of 400W / mm 2 ~600W / mm 2 When the laser is continuously operated for 0.5h to 2h in a laser environment, the temperature rise of the detection end face is ≤15℃.

8. The production method according to claim 5, characterized in that: In step S2, the scanning speed of the laser welding is 5 mm / s to 10 mm / s.

9. The production method according to claim 5, characterized in that: In step S3, the repetition frequency of the femtosecond laser is 80 kHz to 120 kHz.

10. A laser transmission system, characterized in that: include The high-power optical fiber transmission jumper according to any one of claims 1 to 4; a cooling device connected to the fluid interface; A laser is optically coupled to the fiber optic patch cable.

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