Ultrafast laser direct writing fiber bragg grating clamp
Through the integrated design of ultrafast laser direct-write fiber grating fixtures, the problems of limited processing length and difficult to guarantee accuracy in fiber grating preparation are solved, and efficient and stable fiber grating processing is achieved, which is suitable for the wide application of fiber gratings in various fields.
Patent Information
- Application Number
- CN202510685774.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-27
- Publication Date
- 2025-08-01
AI Technical Summary
In the prior art, the preparation method of fiber gratings has problems such as limited processing length and difficult to ensure accuracy, especially in large-scale production, it is difficult to achieve high-precision fiber grating processing.
An ultrafast laser direct-write fiber grating fixture is designed, including a wire feeding device, an optical fiber collection device, an optical fiber fixture platform, a laser processing component and an XY two-dimensional high-precision displacement table. Through the integrated optical fiber fixture platform design, combined with pneumatic adjustment and pressure monitoring functions, the stable delivery and tension of the optical fiber is achieved. It is equipped with a high-precision displacement table and a laser focusing system to ensure processing accuracy and stability.
High-precision processing of fiber gratings in large-scale production is achieved, ensuring the stability and processing quality of fiber gratings, improving processing efficiency, and adapting to different needs of fiber grating preparation.
Smart Images
Figure CN120405832A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of preparing fiber Bragg gratings, and particularly to a fixture for directly writing fiber Bragg gratings by ultrafast laser. Background Art
[0002] A fiber Bragg grating (FBG) is a structure that utilizes the photosensitivity of optical fiber materials to form a periodic refractive index change within the fiber core to achieve specific functions. Currently, fiber Bragg gratings exhibit excellent performance in fields such as optical grating communication, sensing technology, aerospace, and medical applications.
[0003] Currently, common preparation methods include the mask method and the direct writing method. The mask method often requires a high-precision mask template and is difficult to prepare fiber Bragg gratings with a long length. The direct writing method uses an ultrafast laser as an energy source, focuses the focal point inside the optical fiber, and modifies the refractive index of the optical fiber by precisely adjusting the energy density to achieve specific functions. This method has high precision and a wide range of applicable materials. However, due to the extremely small cross-sectional size of the optical fiber, it is necessary to cooperate with a high-precision displacement platform, which limits the processing length. During large-scale processing, it is difficult to guarantee the processing accuracy. Summary of the Invention
[0004] The present invention provides a fixture for directly writing fiber Bragg gratings by ultrafast laser to solve the defects in the prior art of preparing fiber Bragg gratings.
[0005] The present invention provides a fixture for directly writing fiber Bragg gratings by ultrafast laser, including: a wire feeding device for feeding the optical fiber; an optical fiber collecting device for winding up the optical fiber; an optical fiber fixture platform disposed between the wire feeding device and the optical fiber collecting device, on which a second isolation wheel group, a rear tensioning wheel, a center tensioning wheel, a front tensioning wheel, and a first isolation wheel group are sequentially provided along the optical fiber feeding direction; a laser processing assembly for processing the optical fiber; an XY two-dimensional high-precision displacement stage for driving the optical fiber fixture platform to move; and a control system for coordinating the actions of each component.
[0006] According to the fixture for directly writing fiber Bragg gratings by ultrafast laser provided by the present invention, both the first isolation wheel group and the second isolation wheel group are composed of a driving wheel and a driven wheel, the wheel surface is an inwardly concave structure, the material is high-elastic rubber, and the distance between the driving wheel and the driven wheel is adjustable.
[0007] According to the fixture for directly writing fiber Bragg gratings by ultrafast laser provided by the present invention, the center tensioning wheel, the front tensioning wheel, and the rear tensioning wheel are installed on pneumatic telescopic rods, and pneumatic valves are provided on the pneumatic telescopic rods for adjusting the height positions of the respective wheels.
[0008] According to the fixture for directly writing fiber Bragg gratings by ultrafast laser provided by the present invention, a pressure sensor is integrated inside the support of the center tensioning wheel for real-time monitoring of the tension force of the optical fiber.
[0009] An ultrafast laser direct writing fiber grating fixture provided by the present invention, wherein the wheel surfaces of the central tension wheel, the front tension wheel and the rear tension wheel are concave structures, a groove matching the cross-sectional area of the optical fiber is opened at the center, and a retaining ring for preventing the optical fiber from falling off is provided on the wheel body.
[0010] An ultrafast laser direct writing fiber grating fixture provided by the present invention, wherein the ultrafast laser is a femtosecond laser or a picosecond laser, and its wavelength is adaptively selected according to the material of the optical fiber to be processed.
[0011] An ultrafast laser direct writing fiber grating fixture provided by the present invention, wherein the laser processing assembly includes a focusing objective lens, an ultrafast laser and a detection objective lens.
[0012] An ultrafast laser direct writing fiber grating fixture provided by the present invention, wherein the focusing objective lens and the detection objective lens are coaxially arranged and are respectively used for laser focusing and monitoring the processing process.
[0013] An ultrafast laser direct writing fiber grating fixture provided by the present invention, wherein the control system dynamically adjusts the pneumatic valve by feedback pressure sensor data to maintain a constant tension of the optical fiber.
[0014] An ultrafast laser direct writing fiber grating fixture provided by the present invention, wherein the wire feeding device and the optical fiber collecting device are respectively located at both ends of the optical fiber fixture platform to realize continuous feeding and recycling of the optical fiber.
[0015] The ultrafast laser direct writing fiber grating fixture provided by the present invention realizes the cooperative action of multiple gear systems through an integrated optical fiber fixture platform design, is equipped with pneumatic regulation and pressure monitoring functions, can adjust the optical fiber tension state in real time, and ensures processing stability. Combined with a high-precision displacement stage and a laser focusing system, the device can ensure processing accuracy while flexibly adjusting processing parameters to meet different requirements and is compatible with large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.
[0017] Figure 1 is a structural schematic diagram of the ultrafast laser direct writing fiber grating fixture provided by the present invention; Figure 2 is a structural schematic diagram of the optical fiber fixture platform provided by the present invention; Figure 3It is a side view of the isolation wheel set provided by the present invention; Figure 4 It is a side view of the tensioning wheel provided by the present invention; Figure 5 It is a cross-sectional view of the pneumatic telescopic rod provided by the present invention.
[0018] Reference numerals: 10. Optical fiber; 100. Wire feeding device; 200. Optical fiber collecting device; 300. Optical fiber fixture platform; 310. First isolation wheel set; 311. Driving wheel; 312. Driven wheel; 313. Servo motor; 320. Second isolation wheel set; 330. Central tensioning wheel; 331. Snap ring; 340. Front tensioning wheel; 350. Rear tensioning wheel; 360. Pneumatic telescopic rod; 361. Pneumatic valve; 370. Pressure sensor; 400. XY two-dimensional high-precision displacement table; 500. Laser processing assembly; 510. Focusing objective lens; 520. Ultrafast laser; 530. Detection objective lens. Detailed implementation manners
[0019] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the scope of protection of the present invention.
[0020] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.
[0021] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on Figure 1The orientation and position of the ultra-fast laser direct writing fiber grating fixture shown when placed normally are only for the convenience of describing the present invention and simplifying the description. Without contrary statements, these orientation terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present invention; the orientation terms "inside" and "outside" refer to the inside and outside relative to the contour of each component itself.
[0022] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.
[0023] The present invention provides an ultra-fast laser direct writing fiber grating fixture. Refer to Figure 1 , which includes: a wire feeding device 100 for feeding the optical fiber; an optical fiber collecting device 200 for winding the optical fiber; a laser processing assembly 500 for processing the optical fiber; an optical fiber fixture platform 300 disposed between the wire feeding device 100 and the optical fiber collecting device 200, on which a second isolation wheel set 320, a rear tensioning wheel 350, a central tensioning wheel 330, a front tensioning wheel 340, and a first isolation wheel set 310 are sequentially provided along the optical fiber feeding direction; an XY two-dimensional high-precision displacement stage 400 for driving the optical fiber fixture platform 300 to move; and a control system for coordinating the actions of each component. The wire feeding device 100 and the optical fiber collecting device 200 are respectively located at both ends of the optical fiber fixture platform 300 to realize the continuous feeding and recovery of the optical fiber.
[0024] In one embodiment, refer to Figure 2-3 , both the first isolation wheel set 310 and the second isolation wheel set 320 are composed of a driving wheel 311 and a driven wheel 312. The wheel surface is an inward concave structure, and the material is high-elastic rubber. The driving wheel 311 is installed on a bearing support, and the driven wheel 312 is connected to the bearing support through a spring, which is convenient for the optical fiber to be placed into the wheel set during installation and also provides a clamping force for the optical fiber. The isolation wheel set, on the one hand, ensures that the optical fiber located therebetween is always in a tensioned state, and on the other hand, can adjust the transmission speed of the optical fiber during the processing. The distance between the driving wheel 311 and the driven wheel 312 is adjustable. A servo motor 313 is installed behind the driving wheel 311 for driving the driving wheel 311 to rotate.
[0025] In one embodiment, refer to Figure 2 and Figure 5, the center tensioning wheel 330, the front tensioning wheel 340, and the rear tensioning wheel 350 are installed on the pneumatic telescopic rods. Each pneumatic telescopic rod is equipped with a pneumatic valve 361, and the height position of each tensioning wheel can be adjusted through the pneumatic valve 361. And a pressure sensor 370 is provided inside the pneumatic telescopic rod 360 of the center tensioning wheel 330 for real-time monitoring of the tension force of the optical fiber. When the pneumatic valve 361 adjusts the height of the center tensioning wheel 330, the pneumatic telescopic rod 360 rises or falls. The pneumatic valve 361 inflates the pneumatic telescopic rod 360, and the pneumatic telescopic rod 360 rises, the optical fiber will be tightened, and the downward force of the optical fiber will also become larger. After the optical fiber is tightened, it will generate a downward force on the pneumatic telescopic rod 360. The pressure sensor 370 is a pressure gauge and is installed below the pneumatic telescopic rod 360 to measure the downward force generated by the optical fiber on the pneumatic telescopic rod 360. At the same time, the reading of the pressure sensor 370 will increase.
[0026] In one embodiment, referring to Figure 4 , the wheel surfaces of the center tensioning wheel 330, the front tensioning wheel 340, and the rear tensioning wheel 350 are concave structures. A groove matching the cross-sectional area of the optical fiber is opened at the center, and a retaining ring 331 for preventing the optical fiber from falling off is provided on the wheel body.
[0027] In one embodiment, the ultrafast laser 520 is a femtosecond laser or a picosecond laser, and its wavelength is adaptively selected according to the material of the optical fiber to be processed.
[0028] In one embodiment, the laser processing assembly 500 includes a focusing objective lens 510, an ultrafast laser 520, and a detection objective lens 530. The focusing objective lens 510 and the detection objective lens 530 are coaxially arranged and are respectively used for laser focusing and monitoring of the processing process.
[0029] In one embodiment, the control system dynamically adjusts the pneumatic valve 361 by feeding back the data of the pressure sensor 370 to maintain a constant tension of the optical fiber. The control system can adjust the rotation speeds and relative rotation speeds of the first isolation wheel set 310 and the second isolation wheel set 320, can also control the rotation speeds of the collection device and the rollers of the wire feeding device 100, and can also control the pneumatic valve 361 of the tensioning wheel.
[0030] In one embodiment, the ultrafast laser 520 direct writing optical fiber grating fixture further includes a real-time monitoring system. In combination with the control system, the real-time monitoring system is used to monitor the value of the pressure sensor 370 of the center tensioning wheel 330 and feed it back to the control system, and the control system then performs real-time adjustment.
[0031] The specific usage method is as follows: The first step: Install the optical fiber on each wheel system in sequence. Such as Figure 1As shown, the optical fiber fixture platform 300 is installed on the XY two-dimensional high-precision displacement stage 400. The optical fiber is pulled out from the wire feeding device 100, the driven wheel is pulled, the spring elongates, the position of the driven wheel 312 of the second isolation wheel set 320 is raised, the optical fiber is placed between the grooves between the driving wheel 311 and the driven wheel 312, and then the optical fiber is continuously pulled out. The optical fiber is pre-fixed on the rear tensioning wheel 350 through the snap ring 331. The optical fiber is fixed on the center tensioning wheel 330 and the front tensioning wheel 340 in the same way. Then the optical fiber is fixed on the first isolation wheel set 310, and the fixing method is the same as that of the second isolation wheel set 320. The optical fiber is continuously pulled out, and the end of the optical fiber is fixed on the collecting device.
[0032] Step 2: Pre-tighten the optical fiber and adjust the position. Adjust the pneumatic valve 361 of the center tensioning wheel 330 so that the pressure sensor 370 shows a positive pressure to ensure that the optical fiber is in a pre-tightened state. It is also possible to fix the second isolation wheel set 320 and start the first isolation wheel set 310 to adjust the optical fiber to be in a pre-tightened state. Then, the laser focus is focused on the center of the optical fiber located at the center tensioning wheel 330 by adjusting the positions of the XY two-dimensional high-precision displacement stage 400 and the focusing objective lens 510. After the focus position adjustment is completed, the platform position cannot be moved and the pneumatic valve 361 cannot be adjusted during the subsequent processing to ensure the relative position of the focus and the optical fiber center is fixed.
[0033] Step 3: Start processing.
[0034] During the fiber grating etching process, the absolute rotational speeds of the front and rear isolation wheel sets determine the transmission speed of the grating. The precise control of the transmission speed is crucial for the regulation of the etching point intervals within the grating. Specifically, when the transmission speed remains constant, the intervals of the etching points within the grating can be controlled by adjusting the pulse repetition frequency. By changing the pulse repetition frequency, precise regulation of the etching point intervals can be achieved without changing the transmission speed. For example, increasing the pulse repetition frequency will make the etching point intervals smaller, and vice versa. On the other hand, the pulse repetition frequency can be fixed, and the intervals of the etching points within the grating can be controlled by adjusting the transmission speed. In this case, the change in the transmission speed will directly affect the size of the etching point intervals. Specifically, increasing the transmission speed will make the etching point intervals larger, and vice versa. This adjustment method can also achieve precise control of the etching point intervals. For the etching requirements with non-fixed intervals, it can be achieved by real-time adjusting the pulse repetition frequency. This method can dynamically change the etching point intervals during the etching process to meet the requirements of complex grating structures. By precisely controlling the transmission speed and the pulse repetition frequency, precise regulation of the etching point intervals within the grating can be achieved, thus meeting the requirements of different application scenarios.
[0035] The control system can accurately control the rotational speeds and relative rotational speed of the front and rear isolation pulley sets, and the driving wheels 311 and the driven wheels 312 of the front and rear isolation pulley sets ensure that the optical fiber can be transmitted smoothly. By adjusting the rotational speed, the transmission speed of the optical fiber is controlled. During the processing, the value of the pressure sensor 370 of the center tension pulley is monitored in real time. When the pressure exceeds the range, the relative rotational speed of the front and rear isolation pulley systems is adjusted to bring the pressure back to the normal range. It should be particularly noted here that during the processing, the relative position between the laser focus and the center of the optical fiber cross-section should be fixed, so the height of the center tension pulley 330 cannot be adjusted during the processing. Therefore, if it is detected that the optical fiber deviates from the tension state, the height of the front and rear tension pulleys can be adjusted by adjusting the pneumatic valve 361 to tension the grating. The rotational speeds of the rollers of the collection device and the wire feeding device 100 can also be automatically adjusted in real time by the control system to ensure that the optical fiber between the collection device and the first isolation pulley system and between the wire feeding device 100 and the second isolation pulley system is in a slack state to ensure that the optical fiber is not broken.
[0036] Through the integrated design of the optical fiber fixture platform, the present invention realizes the coordinated action of multiple pulley systems, is equipped with pneumatic adjustment and pressure monitoring functions, can adjust the optical fiber tension state in real time, and ensures the processing stability. Combined with the high-precision displacement stage and the laser focusing system, the device can, while ensuring the processing accuracy, meet different requirements by flexibly adjusting the processing parameters (such as rotational speed and pulse frequency) and is compatible with large-scale production. In addition, the real-time monitoring and automatic adjustment mechanism can dynamically adjust the pressure and the optical fiber slack state to ensure the stability and reliability of the processing process, and further improve the processing efficiency and quality. The real-time monitoring system further enhances the intelligence and controllability of the processing process. Generally speaking, while taking into account the processing accuracy and scale, the present invention significantly improves the processing efficiency and quality of the fiber grating, providing strong support for the wide application of the fiber grating in various fields.
[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.
Claims
1. An ultrafast laser direct writing fiber grating fixture, characterized in that Including: A wire feeding device for feeding optical fibers; An optical fiber collecting device for winding up optical fibers; An optical fiber clamping platform is arranged between the wire feeding device and the optical fiber collecting device, and a second isolation wheel group, a rear tensioning wheel, a center tensioning wheel, a front tensioning wheel and a first isolation wheel group are successively arranged thereon along the optical fiber feeding direction; A laser processing component for processing optical fibers; An XY two-dimensional high-precision displacement stage for driving the optical fiber clamping platform to move; A control system for coordinating the actions of each component.
2. The ultra-fast laser direct writing fiber grating fixture according to claim 1, wherein Both the first isolation wheel group and the second isolation wheel group are composed of a driving wheel and a driven wheel, the wheel surface is of a concave structure, the material is high-elastic rubber, and the distance between the driving wheel and the driven wheel is adjustable.
3. The ultra-fast laser direct writing fiber grating fixture according to claim 1, characterized in that The center tensioning wheel, the front tensioning wheel and the rear tensioning wheel are installed on pneumatic telescopic rods, and pneumatic valves are arranged on the pneumatic telescopic rods respectively for adjusting the height positions of the wheels.
4. The ultra-fast laser direct writing fiber grating fixture according to claim 3, characterized in that A pressure sensor is integrated in the support of the center tensioning wheel for real-time monitoring of the tension of the optical fiber.
5. The ultra-fast laser direct writing fiber grating fixture according to claim 1, wherein The wheel surfaces of the center tensioning wheel, the front tensioning wheel and the rear tensioning wheel are of a concave structure, a groove matching the cross-sectional area of the optical fiber is opened at the center, and a retaining ring for preventing the optical fiber from falling off is arranged on the wheel body.
6. The ultra-fast laser direct writing fiber grating fixture according to claim 1, characterized in that, The ultrafast laser is a femtosecond laser or a picosecond laser, and its wavelength is adaptively selected according to the material of the optical fiber to be processed.
7. The ultra-fast laser direct writing fiber grating fixture according to claim 1, characterized in that, The laser processing component includes a focusing objective lens, an ultrafast laser and a detection objective lens.
8. The ultra-fast laser direct writing fiber grating fixture according to claim 7, wherein, The focusing objective lens and the detection objective lens are coaxially arranged and are respectively used for laser focusing and monitoring the processing process.
9. The ultra-fast laser direct writing fiber grating fixture according to claim 1, characterized in that, The control system dynamically adjusts the pneumatic valve by feedback of the pressure sensor data to maintain a constant tension of the optical fiber.
10. The ultrafast laser direct writing fiber grating fixture according to claim 1, wherein The wire feeding device and the optical fiber collecting device are respectively located at both ends of the optical fiber clamping platform to realize continuous feeding and recovery of the optical fiber.