Femtosecond laser flexible transmission device based on hollow-core optical fiber

Abstract

The invention provides a femtosecond laser flexible transmission device based on a hollow-core optical fiber, which comprises a first reflector assembly, a light convergence assembly and a second reflector assembly, a beam expanding collimating lens group is arranged between the second reflector assembly and the light convergence assembly, the femtosecond laser flexible transmission device is also provided with an optical cable, the hollow-core optical fiber is arranged in the optical cable, and the two ends of the optical cable are provided with optical fiber coupling ends. According to the femtosecond laser flexible transmission device, the problem of femtosecond laser flexible transmission is solved, the structure can be conveniently optimized, and the problems of nonlinear absorption, pulse width expansion and the like of laser can be solved through vacuumizing.

Description

Technical Field

[0001] The present invention relates to the field of femtosecond laser optical fiber transmission, and in particular to a femtosecond laser flexible transmission device based on hollow-core optical fiber. Background Art

[0002] Femtosecond lasers have a wide range of applications in medical treatment, material processing, measurement and other fields. However, the extremely high peak power can easily interact with the transmission material and damage the material. Therefore, at present, femtosecond lasers basically use optical elements to expand the beam spot and then transmit it through a mirror group for reflection. Although this reduces the damage to the transmission material, the adaptability of femtosecond laser applications is limited due to the fixed optical path and difficulty in adjustment.

[0003] Some current technologies consider transmitting femtosecond lasers in solid optical fibers. However, due to the high peak power of femtosecond lasers, it is not only easy to damage the optical fiber, but also the interaction between the femtosecond laser and the air produces nonlinear absorption, resulting in reduced laser transmission efficiency. At the same time, the femtosecond laser pulse width will be broadened, reducing the quality of the femtosecond laser. Summary of the Invention

[0004] The present invention provides a femtosecond laser flexible transmission device based on hollow-core optical fiber, which solves the problem of femtosecond laser flexible transmission.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a femtosecond laser flexible transmission device based on hollow-core optical fiber, including a first reflector assembly, a light converging assembly and a second reflector assembly, a beam expander collimator group is provided between the second reflector assembly and the light converging assembly, and an optical cable is also provided, in which a hollow-core optical fiber is provided, and optical fiber coupling ends are provided at both ends of the optical cable, and the optical fiber coupling end at one end of the optical cable is aligned with the light converging assembly.

[0006] In a preferred embodiment, the optical fiber coupling end includes a base body, an inner through hole with two ends passing through is provided in the center of the base body, an optical fiber fixing tube is sleeved in the inner through hole, a front end sleeve and a rear end sleeve are provided at both ends of the base body respectively, the optical fiber fixing tube is provided with a hollow inner cavity, the hollow inner cavity is communicated with the interior of the front end sleeve and the rear end sleeve, one end of the rear end sleeve is connected to the optical cable, the hollow core optical fiber in the optical cable passes through the rear end sleeve to extend into the hollow inner cavity, an optical fiber sleeve is provided at one end of the hollow inner cavity close to the front end sleeve, the optical fiber sleeve fixes the hollow core optical fiber end, an annular clamping cavity is provided between the inner through hole and the optical fiber fixing tube, and the base body is provided with a water inlet hole and a water outlet hole communicated with the annular clamping cavity.

[0007] In the preferred solution, a water inlet groove is provided between the water inlet hole and the annular clamping cavity, a water outlet groove is provided between the annular clamping cavity and the water inlet groove, and a first sealing cover plate is also provided. A transverse thin-walled area is provided on the first sealing cover plate, and the two ends of the transverse thin-walled area are respectively close to the water inlet groove and the water outlet groove, and temperature sensors are provided at both ends of the transverse thin-walled area.

[0008] In the preferred embodiment, a light-transmitting hole and a first light-transmitting mirror for sealing the light-transmitting hole are provided on the side wall of the inner through hole on the base body, a broken notch and a second light-transmitting mirror for sealing the broken notch are provided on the side wall of the optical fiber fixing tube, and a light intensity sensor is also provided. The light intensity sensor detects the light intensity in the hollow cavity through the first light-transmitting mirror and the second light-transmitting mirror.

[0009] In the preferred solution, a third light-transmitting mirror is provided at one end of the front-end sleeve away from the optical fiber fixing tube, the base body is provided with an air inlet hole and an air vent, a transition air cavity connected to the air inlet hole and the air vent is provided, one side of the transition air cavity is open and provided with a second sealing cover plate, the air vent is connected to the interior of the front-end sleeve, and the inner core of the hollow optical fiber is connected to the front-end sleeve.

[0010] In a preferred solution, a cable connection sleeve is provided at one end of the rear end sleeve away from the base body, the cable connection sleeve is sleeved with the optical cable, and the cable connection sleeve is provided with a glue injection hole connected to the interior of the rear end sleeve.

[0011] In the preferred solution, a support sleeve is provided in the rear end sleeve, the lower end of the support sleeve is connected to the optical fiber fixing tube, the upper end of the support sleeve is provided with a supporting sleeve portion, the supporting sleeve portion supports the end of the optical cable and seals the clamping cavity between the optical cable and the cable connecting sleeve, and the side wall of the support sleeve is provided with a hollow portion.

[0012] In a preferred embodiment, the optical fiber fixing tube includes an outer protruding end and an inner sleeve end, the inner sleeve end is arranged in the inner through hole, the outer protruding end is socketed with the end of the inner sleeve end, the outer protruding end and the inner sleeve end are detachable, the optical fiber sleeve is arranged at the end of the outer protruding end, and sealing glue layers are provided at both ends of the inner sleeve end, a first phase change material is provided in the inner sleeve end, and a second phase change material is provided in the outer protruding end.

[0013] In a preferred embodiment, the first reflector assembly and the second reflector assembly both include a first base and a first movable seat, the first base is provided with a plurality of threaded first adjustment bolts, the end of the first adjustment bolt is provided with a rotatable first ball, the first adjustment bolt passes through the first base so that the first ball rests on the first movable seat, the first movable seat is provided with a reflector, the first movable seat is connected to a plurality of first tension springs, the first base is provided with a first baffle rod, and one end of the first tension spring is hooked on the first baffle rod.

[0014] In the preferred solution, the light converging assembly includes a forward and backward translation assembly, which includes a third base and a third movable seat that can move linearly relative to the third base. The third movable seat is connected to a multidimensional adjustment platform, and a converging mirror is provided on the multidimensional adjustment platform.

[0015] The beneficial effects of the present invention are as follows: the femtosecond laser is guided by a reflector group, and after beam expansion and collimation, it is converged in parallel into the hollow-core optical fiber in the optical cable. The optical cable can be bent and moved to ensure the optical performance of the femtosecond laser while realizing flexible transmission in various application scenarios; the optical fiber coupling end integrates multiple functions. First, the heat accumulated at the end of the hollow-core optical fiber is taken away by liquid cooling to prevent burning. Second, through the air path design, air can be pumped from the outside to evacuate the hollow-core optical fiber to avoid the interaction between the femtosecond laser and the air to produce nonlinear absorption, resulting in reduced laser transmission efficiency. At the same time, the femtosecond laser pulse width will be broadened, reducing the quality of the femtosecond laser. Third, it has light leakage and temperature monitoring functions to monitor the status of the optical fiber coupling end in real time; the phase change material is encapsulated in the optical fiber fixing tube to improve the heat transmission efficiency. At the same time, the phase change process keeps the temperature of the optical fiber end constant within a safe range to prevent the optical fiber end from burning due to instantaneous high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings and examples.

[0017] Figure 1 It is a schematic diagram of the component layout of the present invention.

[0018] Figure 2 is a schematic diagram of the reflective component.

[0019] Figure 3 Is the internal structure of the reflection component Figure 1 .

[0020] Figure 4 Is the internal structure of the reflection component Figure 2 .

[0021] Figure 5 This is a side view of the convergence component.

[0022] Figure 6 This is the front view of the convergence component.

[0023] Figure 7 The internal structure of the multi-dimensional adjustment table Figure 1 .

[0024] Figure 8 The internal structure of the multi-dimensional adjustment table Figure 2 .

[0025] Figure 9 This is the structure diagram of the optical cable and coupling end.

[0026] Figure 10 Cross-section of the coupling end Figure 1 .

[0027] Figure 11 Cross-section of the coupling end Figure 2 .

[0028] Figure 12 It is a schematic diagram of the substrate.

[0029] Figure 13 This is the sensor installation structure diagram.

[0030] Figure 14 This is the structural diagram of the transition air cavity.

[0031] Figure 15 This is the installation diagram of the optical fiber fixing tube and support sleeve.

[0032] Figure 16 This is a schematic diagram of the first phase change material injection.

[0033] Figure 17 It is a schematic diagram of the fixed tube and the extended end being installed into the base.

[0034] Figure 18 This is a schematic diagram of the second phase change material injection.

[0035] Figure 19 This is a diagram showing the cable connection sleeve in place.

[0036] Figure 20 This is a schematic diagram of the front end sleeve being assembled in place.

[0037] In the figure: base 1; inner through hole 101; air inlet 102; transition air cavity 103; air vent 104; water inlet hole 105; water outlet hole 106; water inlet groove 107; water outlet groove 108; first sealing cover plate 109; cross-linked thin-walled area 110; temperature sensor 111; light transmission hole 112; first light transmission mirror 113; second light transmission mirror 114; light intensity sensor 115; second sealing cover plate 116; fourth light transmission mirror 117; color change agent bag 118; optical fiber fixing tube 2; optical fiber sleeve Tube 201; hollow inner cavity 202; annular clamping cavity 203; extended end 204; inner sleeve end 205; hollow-core optical fiber 3; sealing adhesive layer 301; first phase change material 302; second phase change material 303; temporary plugging sleeve 304; front sleeve 4; third light-transmitting mirror 401; rear sleeve 5; movable sleeve 501; support sleeve 502; hollow portion 503; support sleeve portion 504; top screw 505; optical cable 6; cable connector 601; glue injection hole 602; end fixing sleeve 7; exhaust hole 701 ; Water inlet 702; Water outlet 703; Wire outlet 704; Outer sheath 705; First reflector assembly 8; First base 801; First movable seat 802; Reflector 803; First adjusting bolt 804; First ball bearing 805; First stop bar 806; First tension spring 807; Light converging assembly 9; Forward and backward translation assembly 901; Lifting frame 902; Multi-dimensional adjustment platform 903; Third base 904; Third movable seat 905; Micrometer screw 906; Telescopic screw 907; Connection Screw sleeve 908; converging mirror 909; second base 910; second movable seat 911; second blocking rod 912; second tension spring 913; second adjusting bolt 914; second ball 915; first tensioning seat 916; second tensioning seat 917; third tension spring 918; third adjusting bolt 919; third ball 920; second reflector assembly 10; beam expander and collimator assembly 11; fiber coupling end 12; base box 13; light-transmitting reserved hole 1301; porous plate 14; laser emitting assembly 15. DETAILED DESCRIPTION

[0038] Example 1: like Figure 1-20 In the figure, a femtosecond laser flexible transmission device based on hollow-core optical fiber includes a first reflector assembly 8, a light converging assembly 9, and a second reflector assembly 10. A beam expander and collimator lens group 11 is provided between the second reflector assembly 10 and the light converging assembly 9. An optical cable 6 is also provided. Optical fiber coupling ends 12 are provided at both ends of the optical cable 6. The optical fiber coupling end 12 at one end of the optical cable 6 is aligned with the light converging assembly 9.

[0039] The first reflector assembly 8, the second reflector assembly 10, the beam expander and collimator lens group 11, and the light converging assembly 9 are arranged in a base box 13. The base box 13 is provided with a porous plate 14, and the installation position of each component can be roughly adjusted. A light-through hole 1301 is provided at one end of the base box 13. The first reflector assembly 8, the second reflector assembly 10, and the beam expander and collimator lens group 11 are all provided with a lifting seat connected to the porous plate 14.

[0040] The external laser emitting component 15 emits a laser which enters the base box 13 from the light-passing reserved hole 1301, is reflected by the first reflector component 8 and the second reflector component 10, and is collimated and expanded by the beam expander and collimator lens group 11. Subsequently, the laser is converged into a concentrated parallel light by the light converging component 9, and enters the optical fiber coupling end 12. After being transmitted through the optical cable 6, it is emitted from the other optical fiber coupling end 12 of the optical cable 6 to the end device.

[0041] In the preferred embodiment, the optical fiber coupling end 12 includes a base body 1, an inner through hole 101 with two ends passing through is provided in the center of the base body 1, an optical fiber fixing tube 2 is sleeved in the inner through hole 101, a front end sleeve 4 and a rear end sleeve 5 are provided at both ends of the base body 1, the optical fiber fixing tube 2 is provided with a hollow inner cavity 202, the hollow inner cavity 202 is communicated with the interior of the front end sleeve 4 and the rear end sleeve 5, one end of the rear end sleeve 5 is connected to the optical cable 6, the hollow core optical fiber 3 in the optical cable 6 passes through the rear end sleeve 5 to extend into the hollow inner cavity 202, an optical fiber sleeve 201 is provided at one end of the hollow inner cavity 202 close to the front end sleeve 4, the optical fiber sleeve 201 fixes the end of the hollow core optical fiber 3, an annular clamping cavity 203 is provided between the inner through hole 101 and the optical fiber fixing tube 2, and the base body 1 is provided with a water inlet hole 105 and a water outlet hole 106 communicated with the annular clamping cavity 203.

[0042] Because the optical fiber's end coupling surface leaks light and generates heat, and due to the high instantaneous power of the femtosecond laser, poor heat dissipation can lead to burnout of the tip. The outer covering of optical cable 6 is typically thick, hindering heat dissipation. The soft covering also causes the actual position of the optical fiber tip to fluctuate, making it difficult to align with other devices. For all these reasons, it is necessary to remove the covering from the end of optical cable 6 to expose the bare hollow-core fiber 3.

[0043] The optical fiber fixing tube 2 is a heat-conducting metal tube. Cooling liquid is introduced into the annular clamp cavity 203 through the water inlet hole 105 to cool the optical fiber fixing tube 2 and the bare fiber inside the optical fiber fixing tube 2. The cooling liquid is discharged from the water outlet hole 106. The external liquid cooling circulation controller continuously circulates the liquid in the annular clamp cavity 203 to remove the heat generated by the optical fiber end.

[0044] The optical fiber sleeve 201 at one end of the optical fiber fixing tube 2 fixes the end of the hollow core optical fiber 3, and the rear end sleeve 5 fixes the optical cable 6, and the bare fiber in between is also fixed.

[0045] The hollow-core optical fiber 3 of the transmission cable is positioned on the axis of the end sleeve through two coupling ends. The combination of the transmission cable and the coupling end forms a standard component. By adjusting the direction of the coupling end, it can be aligned with the laser generator at the front end and the user device at the back end, which not only protects the optical fiber but also simplifies the difficulty of optical path adjustment.

[0046] In the preferred scheme, a water inlet groove 107 is provided between the water inlet hole 105 and the annular clamping cavity 203, a water outlet groove 108 is provided between the annular clamping cavity 203 and the water inlet groove 107, and a first sealing cover plate 109 is also provided. A cross-linked thin-walled area 110 is provided on the first sealing cover plate 109, and the two ends of the cross-linked thin-walled area 110 are respectively close to the water inlet groove 107 and the water outlet groove 108, and temperature sensors 111 are provided at both ends of the cross-linked thin-walled area 110.

[0047] A first sealing cover plate 109 is mounted on the base 1 with flat-head screws, sealing the open ends of the water inlet groove 107 and the water outlet groove 108 to prevent leakage. A transverse recessed groove is machined into the first sealing cover plate 109 to reduce the wall thickness. One end of the recessed groove is located in the water inlet groove 107 area, and the other end is located in the water outlet groove 108 area. Two patch-type temperature sensors 111 are attached here to monitor the inlet and outlet temperatures of the water, providing feedback on the temperature inside the optical fiber fixing tube 2.

[0048] In the preferred embodiment, a light-transmitting hole 112 is provided on the side wall of the inner through hole 101 on the base 1, and a first light-transmitting mirror 113 is provided to seal the light-transmitting hole 112; a broken notch is provided on the side wall of the optical fiber fixing tube 2, and a second light-transmitting mirror 114 is provided to seal the broken notch; and a light intensity sensor 115 is also provided. The light intensity sensor 115 detects the light intensity in the hollow inner cavity 202 through the first light-transmitting mirror 113 and the second light-transmitting mirror 114.

[0049] The light intensity sensor 115 is also mounted on the first sealing cover plate 109 . The first sealing cover plate 109 is provided with a through hole at the light transmission hole 112 and the light intensity sensor 115 is mounted thereon.

[0050] When the optical path is unobstructed, the laser is emitted from the end through the hollow-core optical fiber 3, and very little light leaks from the cladding of the hollow-core optical fiber 3. If the end of the hollow-core optical fiber 3 is burned, the light path is blocked and reflected and refracted backward along the cladding, and leaks into the hollow inner cavity 202 of the optical fiber fixing tube 2, and the light intensity detected by the light intensity sensor 115 surges.

[0051] In the preferred embodiment, a third light-transmitting mirror 401 is provided at one end of the front end sleeve 4 away from the optical fiber fixing tube 2, the base body 1 is provided with an air inlet hole 102 and an air vent 104, a transition air cavity 103 is provided between the air inlet hole 102 and the air vent 104, one side of the transition air cavity 103 is open and provided with a second sealing cover plate 116, the air vent 104 is connected to the interior of the front end sleeve 4, and the inner core of the hollow-core optical fiber 3 is connected to the front end sleeve 4.

[0052] The air inlet 102 is connected to the external negative pressure air path to evacuate the gas in the transition air cavity 103, the interior of the front sleeve 4 and the core of the hollow core optical fiber 3, so that the core of the hollow core optical fiber 3 is in a vacuum state, avoiding the nonlinear effect between the laser and the air.

[0053] A fourth light-transmitting mirror 117 is provided on the second sealing cover plate 116. A color-changing agent package 118 that changes color when exposed to oxygen is placed in the transition air cavity 103. When the vacuum state in the transition air cavity 103 is destroyed, the color-changing agent package 118 can be directly observed to be oxidized and discolored through the fourth light-transmitting mirror 117 on the second sealing cover plate 116, indicating that the inner core of the hollow-core optical fiber 3 is no longer in a vacuum state.

[0054] The rear end sleeve 5 is sheathed with an end fixing sleeve 7. The base body 1 is provided with an outer sheath 705. One end of the outer sheath 705 is sheathed with the end fixing sleeve 7, and the other end of the outer sheath 705 is sheathed with the front end sleeve 4. The end fixing sleeve 7 is provided with an air extraction hole 701, a water inlet hole 702, a water outlet hole 703, and a wire outlet hole 704. The air extraction hole 701 is connected to the air inlet hole 102, the water inlet hole 702 is connected to the water inlet hole 105, and the water outlet hole 703 is connected to the water outlet hole 106. The wiring of the temperature sensor 111 and the light intensity sensor 115 is passed through the wire outlet hole 704. The wire outlet hole 704 can be installed at the integrated electrical terminal. The end fixing sleeve 7 is an integrated installation structure for the pipe joint and the electrical terminal.

[0055] The outer sheath 705 is provided with a transparent observation window near the fourth light-transmitting mirror 117 .

[0056] In a preferred embodiment, a cable connection sleeve 601 is provided at one end of the rear end sleeve 5 away from the base 1 , and the cable connection sleeve 601 is sleeved with the optical cable 6 . The cable connection sleeve 601 is provided with a glue injection hole 602 communicating with the interior of the rear end sleeve 5 .

[0057] The optical cable 6 is pre-bonded to the cable connection sleeve 601. A rotatable movable sleeve 501 is provided at the end of the rear end sleeve 5. The movable sleeve 501 is threadedly connected to the cable connection sleeve 601. After the optical cable 6 is adjusted into place, there are two glue injection holes 602. Glue is injected into the rear end sleeve 5 through one of the glue injection holes 602. The glue fills the inner cavity of the rear end sleeve 5 and the hollow inner cavity 202. The other glue injection hole 602 is exhausted. Wait for the glue to solidify, and the hollow core optical fiber 3 is then fixed.

[0058] Because the rear sleeve 5 has a relatively large inner diameter, this glue injection method requires a large amount of glue. Furthermore, due to the small inner diameter of the hollow inner cavity 202 and the relatively high viscosity of the glue, it can be difficult to completely fill the hollow inner cavity 202 with glue. Furthermore, after this glue injection method, the base 1, optical fiber fixing tube 2, rear sleeve 5, cable connector sleeve 601, and movable swivel sleeve 501 are all bonded together, making them difficult to disassemble for reuse.

[0059] In the preferred solution, a support sleeve 502 is provided in the rear end sleeve 5, the lower end of the support sleeve 502 is sleeved with the optical fiber fixing tube 2, and the upper end of the support sleeve 502 is provided with a supporting sleeve portion 504, which supports the end of the optical cable 6 and seals the clamping cavity between the optical cable 6 and the cable connecting sleeve 601, and the side wall of the support sleeve 502 is provided with a hollow portion 503.

[0060] Due to the high instantaneous power of the femtosecond laser, frequent temperature changes lead to frequent thermal expansion and contraction. Instantaneous high temperature will also accelerate the aging of the glue. Therefore, even if glue is injected into the coupling end, looseness will still occur between the bonded parts after long-term use.

[0061] Glue can be pre-injected from the upper end of the optical fiber fixing tube 2 into the hollow inner cavity 202 through the hollow portion 503 to secure the hollow-core optical fiber 3. Because the support sleeve 504 separates the rear end sleeve 5 and the cable connector sleeve 601, after glue is injected through the glue injection hole 602, only the optical cable 6, the cable connector sleeve 601, and the support sleeve 504 are bonded together, leaving the remaining cavity. This not only reduces the amount of glue injected, but also prevents the cable connector sleeve 601 from bonding to the rear end sleeve 5, the movable sleeve 501, and other components, making the device unreusable. Due to the reduced amount of glue injected, the injection time, glue curing time, and the weight of the coupling end are all significantly reduced.

[0062] After the glue solidifies, the top screw 505 on the movable rotating sleeve 501 is locked to fix the cable connecting sleeve 601.

[0063] If the glue falls off or parts become loose later, you can disassemble the coupling end, cut some cables and optical fibers, reassemble the coupling end and inject glue.

[0064] In the preferred embodiment, the optical fiber fixing tube 2 includes an outer protruding end 204 and an inner sleeve end 205. The inner sleeve end 205 is arranged in the inner through hole 101. The outer protruding end 204 and the inner sleeve end 205 are socketed together. The outer protruding end 204 and the inner sleeve end 205 are detachable. The optical fiber sleeve 201 is arranged at the end of the outer protruding end 204. A sealing rubber layer 301 is provided at both ends of the inner sleeve end 205. A first phase change material 302 is provided in the inner sleeve end 205, and a second phase change material 303 is provided in the outer protruding end 204.

[0065] The first phase change material 302 is a transparent solid-liquid phase change material and does not affect the light intensity detected by the light intensity sensor 115 .

[0066] Since the extended end 204 is closer to the end face of the optical fiber, the second phase change material 303 can be a liquid alloy phase change material with a higher thermal conductivity.

[0067] Phase change materials have a higher thermal conductivity than ordinary glue, accelerating heat dissipation from the fiber end. The temperature of the phase change material remains constant during its phase change, maintaining a low, constant temperature at the fiber end. This prevents excessive thermal expansion and contraction, slowing glue aging.

[0068] The assembly method of the coupling end is: Customized length and diameter specifications of the support sleeve 502 to meet the use; Pre-sleeve the optical fiber fixing tube 2 and the supporting sleeve 502 together; Put the cable connection sleeve 601 onto the optical cable 6 for later use; Strip a certain length of hollow-core optical fiber 3 from the end of the optical cable 6, pass the hollow-core optical fiber 3 through the support sleeve 502 and insert it into the optical fiber fixing tube 2 until it protrudes from the other end of the optical fiber fixing tube 2, leaving enough length at the protruding end, and the optical cable 6 rests on the supporting sleeve 504; A temporary plugging sleeve 304 is passed through the hollow-core optical fiber 3 and sealed at the first end of the inner sleeve end 205. A small amount of glue is injected into the first end of the inner sleeve end 205 through a thin tube. After solidification, a plugging glue layer 301 is formed to fix the hollow-core optical fiber 3. Injecting the first phase change material 302 in liquid phase into the inner sleeve end 205 from the second end; After the first phase change material 302 cools and solidifies, a small amount of glue is injected into the second end of the inner sleeve end 205, and after solidification, a sealing glue layer 301 is formed to fix the hollow core optical fiber 3; Remove the temporary plugging sleeve 304 and insert the extended end 204 into the inner through hole 101; The extended end 204 is sleeved on the hollow core optical fiber 3, and one end of the extended end 204 is sleeved and installed on the inner sleeve end 205, with the open end of the extended end 204 facing upward, and the liquid phase second phase change material 303 is injected into the extended end 204; After the second phase change material 303 solidifies, the inner and outer walls of the optical fiber sleeve 201 are coated with glue and sleeved onto the hollow core optical fiber 3. The optical fiber sleeve 201 is inserted into the extended end 204, with the end resting against the end of the solid second phase change material 303; After the fixing glue of the optical fiber sleeve 201 is solidified, the hollow core optical fiber 3, the optical fiber sleeve 201 and the end of the extended end 204 away from the base 1 are cut flat; The movable sleeve 501 and the cable connection sleeve 601 are locked together, and glue is injected into the space between the support sleeve 504 and the cable connection sleeve 601 through the glue injection hole 602. After the glue solidifies, the optical cable 6, the cable connection sleeve 601 and the support sleeve 504 are connected as one; Install the front end casing 4, outer sheath 705 and other structures.

[0069] In the preferred embodiment, the first reflector assembly 8 and the second reflector assembly 10 both include a first base 801 and a first movable seat 802. The first base 801 is provided with a plurality of threaded first adjusting bolts 804, and the end of the first adjusting bolt 804 is provided with a rotatable first ball 805. The first adjusting bolt 804 passes through the first base 801 so that the first ball 805 rests on the first movable seat 802. The first movable seat 802 is provided with a reflector 803, and the first movable seat 802 is connected with a plurality of first tension springs 807. The first base 801 is provided with a first baffle 806, and one end of the first tension spring 807 is hooked on the first baffle 806.

[0070] The first reflector assembly 8 is generally rectangular or angled. For example, the angled type has a first adjustment bolt 804 at each of its three corners. A first stopper 806 and a first tension spring 807 are positioned between adjacent first adjustment bolts 804. The first movable seat 802 and the first tension spring 807 can be pre-welded. A through-hole is provided in the first base 801, into which a first stopper 806 is secured. The first tension spring 807 extends into the pre-reserved hole and hooks onto the first stopper 806. The two first stoppers 806 are oriented perpendicularly. Therefore, rotating one of the first adjustment bolts 804 causes the first movable seat 802 to oscillate. Consequently, the reflector 803 can oscillate in all directions, changing the laser reflection path.

[0071] When the first adjusting bolts 804 are adjusted synchronously, the first movable seat 802 moves parallel to the first base 801 , the spacing is changed, and the reflector 803 can move horizontally.

[0072] The first base 801 is mounted on the lifting frame of the first reflector assembly 8 .

[0073] The beam expander and collimator lens group 11 adopts a double convex lens group or a combination of concave and convex lenses, and the distance between the two mirrors is adjustable.

[0074] In the preferred embodiment, the light converging component 9 includes a forward and backward translation component 901, the forward and backward translation component 901 includes a third base 904 and a third movable seat 905 that can move linearly relative to the third base 904, and the third movable seat 905 is connected to a multi-dimensional adjustment platform 903, and the multi-dimensional adjustment platform 903 is provided with a converging mirror 909.

[0075] The multi-dimensional adjustment platform 903 includes a second base 910 and a second movable seat 911. The converging mirror 909 is installed on the second movable seat 911. The second base 910 is connected to the third movable seat 905 through the lifting frame 902. The second base 910 is provided with a plurality of threaded second adjusting bolts 914. The end of the second adjusting bolt 914 is provided with a rotatable second ball 915. The second ball 915 rests on the second movable seat 911. The second base 910 and the second movable seat 911 are each provided with a plurality of second gears 912 and a plurality of second tension springs 913. The two ends of each second tension spring 913 are respectively hooked on each second gear 912, so that the converging mirror 909 can swing in all directions.

[0076] A micrometer screw 906 is provided on one side of the third base 904 , and a telescopic screw 907 of the micrometer screw 906 is threadedly engaged with a connecting screw sleeve 908 on the third movable base 905 , so that the position of the third movable base 905 can be adjusted.

[0077] The second base 910 is provided with a first tensioning seat 916 and a second tensioning seat 917 in two vertical directions. The first tensioning seat 916 and the second tensioning seat 917 both include a third tension spring 918 hooked on the second movable seat 911 and a third adjusting bolt 919 with a third ball 920 resting on the second movable seat 911. The position of the converging mirror 909 in two orthogonal directions can be adjusted, and a linear three-dimensional movable structure can be formed in conjunction with the moving structure of the third movable seat 905.

[0078] Example 2: A flexible transmission device for femtosecond laser based on hollow-core optical fiber. The femtosecond laser enters the coupling device from the left side of the device, and enters the hollow-core optical fiber cable on the right side through beam expansion and collimation coupling. The output head outputs the femtosecond laser, and the optical cable can bend and move to achieve flexible transmission.

[0079] The light beam enters the device through free transmission in space, undergoes two reflections, passes through the double lens, realizes the collimation and beam expansion of the beam divergence angle, and is focused by the convex lens to converge into a parallel concentrated beam.

[0080] The two reflectors include but are not limited to two-axis or three-axis adjustable mirror mounts, matching and adjustment.

[0081] The double lens includes but is not limited to a double convex lens group or a concave-convex combination.

[0082] If the light beam has a small divergence angle and a large spot, the collimating beam expander lens can be eliminated and a converging convex lens can be used directly for focusing.

[0083] After the light beam passes through the converging convex lens, it forms a light spot near the focal length of the converging convex lens, which may have a certain position difference with the core of the hollow-core fiber. Therefore, the converging convex lens can be mounted on a three-dimensional movable platform, and the overall coordination can achieve fine movement of the focused light spot in three-dimensional space.

[0084] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A femtosecond laser flexible transmission device based on hollow-core optical fiber, characterized by: The invention comprises a first reflector assembly (8), a light converging assembly (9) and a second reflector assembly (10), wherein a beam expanding collimating lens group (11) is provided between the second reflector assembly (10) and the light converging assembly (9), and an optical cable (6) is provided. A hollow-core optical fiber (3) is provided in the optical cable (6), and optical fiber coupling ends (12) are provided at both ends of the optical cable (6). The optical fiber coupling end (12) at one end of the optical cable (6) is aligned with the light converging assembly (9).

2. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 1, characterized in that: The optical fiber coupling end (12) includes a base (1), the base (1) is provided with an inner through hole (101) with two ends extending therethrough in the center, an optical fiber fixing tube (2) is sleeved in the inner through hole (101), the base (1) is provided with a front sleeve (4) and a rear sleeve (5) at both ends, the optical fiber fixing tube (2) is provided with a hollow inner cavity (202), the hollow inner cavity (202) is communicated with the interior of the front sleeve (4) and the rear sleeve (5), one end of the rear sleeve (5) is connected to the optical cable (6), and the optical cable ( 6) passes through the rear end sleeve (5) to extend into the hollow inner cavity (202); an optical fiber sleeve (201) is provided at one end of the hollow inner cavity (202) close to the front end sleeve (4); the optical fiber sleeve (201) fixes the end of the hollow optical fiber (3); an annular clamping cavity (203) is provided between the inner through hole (101) and the optical fiber fixing tube (2); and the base body (1) is provided with a water inlet hole (105) and a water outlet hole (106) connected to the annular clamping cavity (203).

3. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 2, characterized in that: A water inlet groove (107) is provided between the water inlet hole (105) and the annular clamping cavity (203), a water outlet groove (108) is provided between the annular clamping cavity (203) and the water inlet groove (107), and a first sealing cover plate (109) is further provided. A transverse thin-walled area (110) is provided on the first sealing cover plate (109), and two ends of the transverse thin-walled area (110) are respectively close to the water inlet groove (107) and the water outlet groove (108), and temperature sensors (111) are provided at both ends of the transverse thin-walled area (110).

4. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 2, characterized in that: A light-transmitting hole (112) and a first light-transmitting mirror (113) for sealing the light-transmitting hole (112) are provided on the side wall of the inner through hole (101) of the base body (1). A broken notch and a second light-transmitting mirror (114) for sealing the broken notch are provided on the side wall of the optical fiber fixing tube (2). A light intensity sensor (115) is also provided. The light intensity sensor (115) detects the light intensity in the hollow inner cavity (202) through the first light-transmitting mirror (113) and the second light-transmitting mirror (114).

5. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 2, characterized in that: A third light-transmitting mirror (401) is provided at one end of the front sleeve (4) away from the optical fiber fixing tube (2), the base body (1) is provided with an air inlet hole (102) and an air vent (104), a transition air cavity (103) is provided between the air inlet hole (102) and the air vent (104), one side of the transition air cavity (103) is open and provided with a second sealing cover plate (116), the air vent (104) is communicated with the interior of the front sleeve (4), and the inner core of the hollow-core optical fiber (3) is communicated with the front sleeve (4).

6. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 2, characterized in that: A cable connection sleeve (601) is provided at one end of the rear end sleeve (5) away from the base body (1), the cable connection sleeve (601) is sleeved with the optical cable (6), and the cable connection sleeve (601) is provided with a glue injection hole (602) communicating with the interior of the rear end sleeve (5).

7. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 6, characterized in that: A support sleeve (502) is provided in the rear end sleeve (5), the lower end of the support sleeve (502) is sleeved with the optical fiber fixing tube (2), the upper end of the support sleeve (502) is provided with a support sleeve portion (504), the support sleeve portion (504) supports the end of the optical cable (6) and seals the clamping cavity between the optical cable (6) and the cable connecting sleeve (601), and the side wall of the support sleeve (502) is provided with a hollow portion (503).

8. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 7, characterized in that: The optical fiber fixing tube (2) comprises an outer extension end (204) and an inner sleeve end (205), the inner sleeve end (205) is arranged in the inner through hole (101), the outer extension end (204) and the inner sleeve end (205) are sleeved together, the outer extension end (204) and the inner sleeve end (205) are detachable, the optical fiber sleeve (201) is arranged at the end of the outer extension end (204), both ends of the inner sleeve end (205) are provided with a sealing glue layer (301), the inner sleeve end (205) is provided with a first phase change material (302), and the outer extension end (204) is provided with a second phase change material (303).

9. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 1, characterized in that: The first reflector assembly (8) and the second reflector assembly (10) both comprise a first base (801) and a first movable base (802); the first base (801) is provided with a plurality of first adjusting bolts (804) connected by threads; the ends of the first adjusting bolts (804) are provided with rotatable first balls (805); the first adjusting bolts (804) pass through the first base (801) so that the first balls (805) abut against the first movable base (802); the first movable base (802) is provided with a reflector (803); the first movable base (802) is connected with a plurality of first tension springs (807); the first base (801) is provided with a first blocking rod (806); one end of the first tension spring (807) is hooked onto the first blocking rod (806).

10. The hollow-core fiber-based femtosecond laser flexible transmission device according to claim 1, characterized in that: The light converging assembly (9) comprises a front-to-back translation assembly (901), the front-to-back translation assembly (901) comprises a third base (904) and a third movable seat (905) movable linearly relative to the third base (904), the third movable seat (905) being connected to a multi-dimensional adjustment platform (903), and the multi-dimensional adjustment platform (903) being provided with a converging mirror (909).

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