CN115327694A - A clamping device for multi-core fiber Bragg grating laser direct writing - Google Patents

Abstract

The application discloses a clamping device for multi-core fiber Bragg grating laser direct writing, and belongs to the field of fiber processing. The fixing frame of the device comprises a fixing plate, two end plates and two supporting tables; two ends of the fixed plate are respectively provided with an end plate, and the surface of the end plate is vertical to the surface of the fixed plate, so that a placing space is formed inside the fixed frame; the two supporting tables are positioned in the placing space, and one ends of the two supporting tables are fixed with the fixing plate; one side of the fixing plate, which is far away from the placing space, is arranged on the three-dimensional movement mechanism; two ends of the placing table are respectively arranged on the two supporting tables, the multi-core optical fiber is placed at the position of the slit of the placing table, and the extending direction of the multi-core optical fiber is parallel to the length direction of the placing table; and the two end plates are provided with a rotating mechanism on one side close to the placing space, and the rotating mechanisms are used for clamping two ends of the multi-core optical fiber and can drive the multi-core optical fiber to rotate along the axis of the multi-core optical fiber. The device can realize high-precision positioning and regulating functions when the multi-core fiber Bragg grating laser direct writing is carried out.

Description

A clamping device for laser direct writing of multi-core fiber Bragg gratings

technical field

The present application relates to the technical field of optical fiber processing, in particular to a clamping device for laser direct writing of multi-core optical fiber Bragg gratings.

Background technique

Fiber grating is a kind of diffraction passive filter device. The processing of fiber grating is based on certain technical means to periodically modulate the refractive index of the fiber core along the axial direction, and then make it resonate with the conduction optical signal of a specific wavelength to achieve the effect of spectral filtering. Its function is essentially equivalent to forming a narrow-band (projection or reflection) filter or mirror in the fiber core. When a beam of wide-spectrum light passes through the fiber Bragg grating, the wavelengths that meet the Bragg resonance conditions in the fiber will be reflected, and the rest of the wavelengths will continue to propagate through the fiber Bragg grating. Usually, the period of the optical fiber core refractive index modulation structure is in the range of submicron to hundreds of microns. Because the fiber grating has a series of excellent performances such as large resonant wavelength control range, small additional loss, small size, and easy coupling with optical fibers, and its resonant wavelength is sensitive to changes in the external environment such as temperature, strain, refractive index, and concentration. Therefore, Fiber Bragg gratings have been widely used in the fields of fiber lasers, fiber optic communications, and optical sensing.

Multi-core grating is a new type of fiber diffraction device developed on the basis of single-core fiber grating. Due to its advantages of large capacity and strong multiplexing performance, multi-core grating has been used in the measurement and measurement of displacement, velocity, acceleration, temperature and other parameters. The field of sensing has shown significant advantages and has been rapidly expanded and applied in other related fields.

The traditional manufacturing method of fiber Bragg grating is to use the photosensitivity of the fiber material to write the incident coherent light field pattern into the fiber core through ultraviolet exposure, and to generate periodic refractive index changes along the axis of the fiber core in the fiber, thereby forming a permanent The defect of this manufacturing method is that it strongly depends on the photosensitive properties of the fiber material, so it is only suitable for the processing of a small number of fiber gratings.

Laser direct writing methods, especially femtosecond laser direct writing to fabricate fiber Bragg gratings, have changed the mode of fabricating fiber Bragg gratings by ultraviolet exposure. First of all, instead of relying on the photosensitive properties of the fiber material itself, the nonlinear absorption induced by the focused laser can be directly used to realize direct processing of fibers of different materials, and the spectral modulation intensity of the processed Bragg grating can reach 50dB. Secondly, there is no need for expensive phase masks, which reduces processing costs; by adjusting the scanning speed, fiber gratings of any resonant wavelength can be written; by writing at a non-uniform speed, chirp and wide-band Bragg gratings can also be written , therefore, the processing flexibility is greatly improved. Finally, the femtosecond laser direct writing process also has three-dimensional writing capabilities, which can write Bragg gratings of different periods at different core positions of the multi-core grating. In view of the above reasons, the laser direct writing method has been more and more widely used in the processing of fiber Bragg gratings, especially multi-core fiber gratings.

However, it should be pointed out that in the process of direct laser writing of fiber gratings, the challenge brought by the fiber cylinder to online microscopic imaging observation makes it difficult to distinguish the vertical distance between the laser focus and the fiber core to be written, and thus cannot Realize high-precision positioning function. This problem is particularly prominent in the laser direct writing process of multi-core fiber Bragg gratings. Therefore, solving the microscopic imaging problem in laser direct writing fiber gratings and realizing high-precision positioning of the fiber core is of great significance for fiber grating processing, especially for multi-core fiber grating processing.

Contents of the invention

The present invention aims to provide a clamping device for laser direct writing of multi-core fiber Bragg gratings, which can realize high-precision positioning function during laser direct writing of multi-core fiber Bragg gratings.

An embodiment of the present invention provides a clamping device for laser direct writing of multi-core fiber Bragg gratings, including a fixing frame, a rotating mechanism and a placement table; the fixing frame includes a fixing plate, two end plates and two supports platform; two ends of the fixed plate are respectively provided with an end plate, and the surface of the end plate is perpendicular to the surface of the fixed plate, so that the inside of the fixed frame forms a placement space; the two supporting platforms are located In the placement space, one end is fixed to the fixed plate; the side of the fixed plate away from the placement space is set on the three-dimensional movement mechanism; the placement table is long, and its two ends are respectively set on On the two supporting platforms, the placing platform is provided with a slit penetrating from top to bottom, and the multi-core optical fiber is placed at the position of the slit and its extending direction is parallel to the length direction of the placing platform; two pieces The end plate is provided with a rotation mechanism on the side close to the placement space, the rotation mechanism is used to clamp the two ends of the multi-core optical fiber, and can drive the multi-core optical fiber along its own axis rotate.

In a possible implementation manner, the rotation mechanism includes an electric control rotation table, a connector, and an optical fiber clamp; the electric control rotation table is fixed to the end plate; the connection member includes a cylinder and a crescent cylinder; One end of the crescent cylinder is connected to the end face of the cylinder, and the plane faces the axis of the cylinder; the outer wall of the cylinder is clamped in the rotation mounting hole of the electric control rotary table; the optical fiber clamp is set on The plane of the crescent cylinder is used to clamp one end of the multi-core optical fiber, and the optical fiber clamp, the connecting piece and the electric control rotating table are coaxial.

In a possible implementation, the clamping device for laser direct writing of multi-core fiber Bragg gratings also includes a lifting mechanism; one end of the lifting mechanism is connected to any one of the rotating mechanisms, and is used to drive the rotating mechanism lift.

In a possible implementation manner, the placing table includes a placing plate and an optical fiber focusing and placing assembly; both the placing plate and the optical fiber focusing and placing assembly are strip-shaped; on the support platform, and it is provided with the slit penetrating from top to bottom, and the upper side of the slit is used to place the optical fiber focusing and placing assembly; the optical fiber focusing and placing assembly includes a first glass substrate, a second Two glass substrates and a focusing medium; the focusing medium is arranged between the first glass substrate and the second glass substrate, and the focusing medium is provided with a placement hole penetrating along its own axial direction, and the placement hole is used for The multi-core optical fiber is installed; the second glass substrate rests on the upper side of the slit.

In a possible implementation manner, the optical fiber focusing and placing assembly further includes a hollow glass tube; the hollow glass tube is placed between the first glass substrate and the second glass substrate, and the focusing medium is disposed on The periphery of the hollow glass tube is located between the first glass substrate and the second glass substrate; the inner cavity of the hollow glass tube is used for installing the multi-core optical fiber.

In a possible implementation manner, the focusing medium includes a photosensitive adhesive or a refractive index matching liquid.

In a possible implementation manner, the upper surface of the second glass substrate is a plane, or the upper surface is concave to form a cuboid through groove, or the upper surface is concave to form a triangular prism through groove.

In a possible implementation manner, the placing platform further includes a first elastic member and a first micro-adjustment rod; one end of the placing platform is fixed to one of the supporting platforms; the other supporting platform includes a bottom plate, the One end of the bottom plate is connected to the fixed plate, and a first through hole is arranged on the bottom plate, and the axis of the first through hole is perpendicular to the top surface of the bottom plate; the front end of the first fine-motion adjustment rod passes through The first through hole abuts against the bottom surface of the support platform; the first elastic member is arranged between the top surface of the bottom plate and the bottom surface of the placement platform; and/or, the placement platform further includes The second elastic member and the second fine-motion adjustment rod; the other support platform also includes a side plate, the side plate is arranged on the end of the bottom plate away from the fixed plate, and the surface of the side plate is in line with the fixed plate. The top surface of the bottom plate is vertical; the side plate is provided with a second through hole, the axis of the second through hole is perpendicular to the side of the side plate; the front end of the second micro-adjustment rod passes through the first The two through holes are behind the first side of the support platform; the second elastic member is arranged between the fixing plate and the second side of the support platform, or is arranged between the first side and the second side of the support platform. between the side panels.

One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

A clamping device for laser direct writing of multi-core fiber Bragg gratings provided by an embodiment of the present invention includes a fixing frame, a rotating mechanism and a placing table. The fixed frame includes a fixed plate, two end plates and two supporting platforms. An end plate is provided at both ends of the fixing plate, and the surface of the end plate is perpendicular to the surface of the fixing plate, so that the inside of the fixing frame forms a storage space. The two supporting platforms are located in the placement space, and one end is fixed with the fixing plate. The side of the fixed plate facing away from the placement space is arranged on the three-dimensional motion mechanism. The placement platform is long, and its two ends are respectively set on two support platforms. The placement platform is provided with a slit that runs through from top to bottom. The multi-core optical fiber is placed at the position of the slit and its extension direction is the same as the length of the placement platform direction parallel. The two end plates are provided with a rotating mechanism on the side close to the placement space. The rotating mechanism is used to clamp the two ends of the multi-core optical fiber and can drive the multi-core optical fiber to rotate along its own axis. In practice, when laser writing multi-core optical fiber, the multi-core optical fiber is installed on the placement table, and the rotating mechanism can clamp the two ends of the multi-core optical fiber to make the whole of the multi-core optical fiber in a straight line and drive the multi-core optical fiber to rotate, so that the multi-core optical fiber The core of each optical fiber is in a straight line. During the laser writing process, the rotation mechanism and the three-dimensional motion mechanism work together to adjust the core position of the multi-core fiber in real time, thereby realizing the high-precision positioning and control functions required by the multi-core fiber. Positioning and precise laser writing of each fiber core of multiple multi-core fibers.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings that need to be used in the description of the embodiments of the present invention. Obviously, the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

FIG. 1 is a schematic structural view of a clamping device for multi-core fiber Bragg grating laser direct writing provided by an embodiment of the present application;

Fig. 2 is a partial enlarged view 1 of Fig. 1;

Fig. 3 is a partial enlarged view 2 of Fig. 1;

FIG. 4 is a schematic structural diagram of an optical fiber focusing and placing assembly provided in an embodiment of the present application;

Fig. 5 is a schematic structural diagram of another optical fiber focusing and placing assembly provided by the embodiment of the present application;

Fig. 6 is a schematic structural diagram of another optical fiber focusing and placement assembly provided by the embodiment of the present application;

FIG. 7 is a schematic diagram of a laser direct writing multi-core fiber Bragg grating provided by an embodiment of the present application.

Icons: 1-fixed frame; 11-fixed plate; 12-end plate; 13-support platform; 131-bottom plate; 132-side plate; 2-rotation mechanism; Crescent cylinder; 222-cylinder; 23-fiber fixture; 3-placement platform; 31-slit; 32-placement plate; 33-fiber focus placement assembly; 331-first glass substrate; 333-focusing medium; 334-hollow glass tube; 34-first micro-adjustment rod; 35-second micro-adjustment rod; 4-three-dimensional motion mechanism; 41-X-axis motion structure; 42-Y-axis motion structure; 43 -Z-axis motion structure; 5-multi-core optical fiber; 51-fiber core; 52-fiber cladding; 6-lifting mechanism; 7-laser beam; 8-optical microscope; 81-focusing mirror; 82-imaging module; 83 - lighting source; 84 - converging light; 9 - dichroic mirror.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer " and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, Constructed and operative in a particular orientation and therefore are not to be construed as limitations of the invention. The terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance. In addition, the terms "installation", "connection" and "connection" should be interpreted in a broad sense, for example, it can be fixed connection, detachable connection, or integral connection; it can be mechanical connection or electrical connection; it can be It can be directly connected, or indirectly connected through an intermediary, and can be internal communication between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present invention according to specific situations.

Referring to FIGS. 1 to 3 , the embodiment of the present invention provides a clamping device for laser direct writing of multi-core fiber Bragg gratings, including a fixing frame 1 , a rotating mechanism 2 and a placing table 3 . The fixed frame 1 includes a fixed plate 11 , two end plates 12 and two supporting platforms 13 . An end plate 12 is respectively arranged at the two ends of the fixed plate 11, and the surface of the end plate 12 is perpendicular to the surface of the fixed plate 11, so that the overall shape of the fixed frame 1 is a U-shaped cage frame, so that the inside of the fixed frame 1 Create a storage space. Two supporting platforms 13 are located in the placing space, and one end is fixed with the fixing plate 11 .

The side of the fixed plate 11 away from the placement space is arranged on the three-dimensional motion mechanism 4, specifically, the fixed plate 11 is provided with mounting holes, and the side of the fixed plate 11 away from the placement space is connected to the three-dimensional motion mechanism by fixing parts such as screws. 4 fixed. Wherein, the three-dimensional motion mechanism 4 includes an X-axis motion structure 41, a Y-axis motion structure 42, and a Z-axis motion structure 43. As shown in Figure 1, the three-dimensional motion mechanism 4 can drive the clamping device of the present application along the X, Y, and Z directions. three-dimensional movement.

The placement table 3 is in the shape of a strip, and its two ends are respectively arranged on two supporting tables 13. The placement table 3 is provided with a slit 31 penetrating from top to bottom, and the multi-core optical fiber 5 is placed at the position of the slit 31 and extends The direction is parallel to the longitudinal direction of the placing table 3 .

Fig. 7 shows the schematic diagram of laser direct writing multi-core fiber Bragg grating, laser beam 7 shoots to dichroic mirror 9 and is reflected by dichroic mirror 9, then passes through focusing mirror 81 of optical microscope 8 (usually about N _A =0.4 Microfocusing objective lens) is focused and injected into the fiber core 51 of the multi-core optical fiber 5 for laser writing. The illumination light source 83 of the optical microscope 8 is placed on the bottom of the placing table 3 , and then the illuminating light source 83 is converged to the slit 31 of the placing table 3 by the converging lamp 84 of the optical microscope 8 , and illuminates the multi-core optical fiber 5 through the slit 31 . The imaging module 82 of the optical microscope 8 is arranged on the side away from the multi-core optical fiber 5 of the dichroic mirror 9, the dichromatic mirror 9 can transmit the illumination light source 83 to perform imaging in the imaging module 82, and the imaging module 82 can observe the writing of the multi-core optical fiber 5 state. As shown in FIG. 7 , the slit 31 is trapezoidal in a cross section perpendicular to the length direction of the placing table 3 . Since it is necessary for the illumination light source 83 to pass through the multi-core optical fiber 5 and then pass through the dichroic mirror 9, the writing state of the multi-core optical fiber 5 can be fed back to the imaging module 82. The section of the slit 31 is trapezoidal, which has a better converging effect on the illuminating light source 83 , thereby making the imaging effect better. Certainly, the slit 31 may also be rectangular in a section perpendicular to the length direction of the placing table 3 .

A rotating mechanism 2 is provided on the side of the two end plates 12 close to the storage space. The rotating mechanism 2 is used to clamp the two ends of the multi-core optical fiber 5 and can drive the multi-core optical fiber 5 to rotate along its own axis.

In practical application, when the fiber laser is directly written, the microscopic imaging error is difficult to distinguish the vertical distance between the laser focus and the fiber core to be written, so that the high-precision positioning function cannot be realized. When the laser directly writes the multi-core fiber Bragg grating, since there are many fiber cores 51, only one of the fiber cores 51 is directly written by the laser at a time. The core 51 is in a spiral shape, which will cause confusion in the positions of the cores 51 of multiple optical fibers, and then cause the laser to write the first fiber core, but may write on other fiber cores such as the second or third fiber. There are multiple optical fiber cores 51, and thus the high-precision positioning function of the multi-core optical fiber 5 is highly required. Otherwise, the optical fiber core 51 written by the laser will not be the core originally expected to be laser-written, and the laser writing process will be confused. . The rotation mechanism 2 provided by the present application can firmly clamp the two ends of the multi-core optical fiber 5, and can drive the multi-core optical fiber 5 to rotate along its own axis, so that when the multi-core optical fiber 5 is twisted or rotated as a whole, multiple The position of the core optical fiber 5 is such that the optical fiber core 51 is always kept straight. At the same time, the rotating mechanism 2 and the three-dimensional motion mechanism 4 work together to make the multi-core optical fiber 5 form a multi-dimensional movement during laser writing, and adjust the position of the fiber core 51 of the multi-core optical fiber 5 in real time, so as to meet the requirements of the multi-core optical fiber 5. High-precision positioning function, so as to realize the positioning of each fiber core 51 of the multi-core optical fiber 5 .

Of course, the two end plates 12 are provided with a rotating mechanism 2 on the side close to the storage space, which can not only clamp the two ends of the multi-core optical fiber 5 well, but also make the multi-core optical fiber 5 linear as a whole. 5. When rotation is required, one of the rotating mechanisms 2 can be used to drive the multi-core optical fiber 5 to rotate. When the workload of rotation is large, two rotating mechanisms 2 can be allowed to work simultaneously and drive the multi-core optical fiber in opposite directions. 5 rotation, thereby improving the efficiency of the linearization of the multi-core optical fiber 5 and saving time. Of course, setting up two rotating mechanisms 2 can also facilitate their switching, thereby prolonging their service life, and further prolonging the service life of the clamping device.

A clamping device for laser direct writing of multi-core fiber Bragg gratings provided by an embodiment of the present invention includes a fixing frame 1 , a rotating mechanism 2 and a placing table 3 . The fixed frame 1 includes a fixed plate 11 , two end plates 12 and two supporting platforms 13 . Two ends of the fixing plate 11 are respectively provided with an end plate 12 , and the surface of the end plate 12 is perpendicular to the surface of the fixing plate 11 , so that the inside of the fixing frame 1 forms a storage space. Two supporting platforms 13 are located in the placing space, and one end is fixed with the fixing plate 11 . The side of the fixed plate 11 facing away from the placement space is arranged on the three-dimensional motion mechanism 4 . The placement table 3 is in the shape of a strip, and its two ends are respectively arranged on two supporting tables 13. The placement table 3 is provided with a slit 31 penetrating from top to bottom, and the multi-core optical fiber 5 is placed at the position of the slit 31 and extends The direction is parallel to the longitudinal direction of the placing table 3 . The two end plates 12 are provided with a rotating mechanism 2 on the side close to the storage space. The rotating mechanism 2 is used to clamp the two ends of the multi-core optical fiber 5 and can drive the multi-core optical fiber 5 to rotate along its own axis. In practice, when laser writing the multi-core optical fiber 5, the multi-core optical fiber 5 is installed on the placement table 3, and the rotating mechanism 2 can clamp the two ends of the multi-core optical fiber 5 so that the whole is in a straight line and drives the multi-core optical fiber 5 to rotate. Therefore, each optical fiber core 51 of the multi-core optical fiber 5 is in a straight line. During the laser writing process, the rotation mechanism 2 and the three-dimensional motion mechanism 4 work together to adjust the core position of the multi-core optical fiber 5 in real time, thereby realizing the multi-core optical fiber 5 The required high-precision positioning and control functions can further realize the positioning and precise laser writing of each fiber core 51 of the multiple multi-core optical fibers 5 .

Continuing to refer to FIGS. 1 to 3 , the rotating mechanism 2 of the clamping device for multi-core fiber Bragg grating laser direct writing provided by the embodiment of the present application includes an electronically controlled rotary table 21 , a connecting piece 22 and a fiber clamp 23 .

Among them, the electronically controlled rotary table 21 is a device that converts the rotary motion of the motor into the rotary motion of the table top of the translation stage, which is driven by a stepping motor and can automatically adjust the angle. The precision machining worm gear transmission is adopted, and the transmission is fast and precise. Precise digital shaft system design, high precision and large load capacity.

The electric control rotary table 21 is fixed with the end plate 12 . Specifically, the electronically controlled rotating table 21 is fixed to the side of the end plate 12 close to the placement space by fixing members such as screws. Since there is a rotation installation hole in the middle of the electric control rotation platform, but the fiber holder 23 cannot be directly installed in the rotation installation hole, so the rotation mechanism 2 also includes a connector 22 to facilitate the installation of the fiber holder 23 .

The connecting piece 22 includes a cylinder 222 and a crescent cylinder 221 . One end of the crescent cylinder 221 is integrally connected with the end face of the cylinder 222, and the plane faces the axis of the cylinder 222. In practice, the outer surface of the crescent cylinder 221 and the outer surface of the cylinder 222 are on the same cylinder surface, and the crescent cylinder 221 The length of the radius is the same as the length of the radius of the cylinder 222. The outer wall of the cylinder 222 is clamped in the rotation installation hole of the electric control rotation table 21 . The optical fiber clamp 23 is arranged on the plane of the crescent cylinder 221 for clamping one end of the multi-core optical fiber 5 , and the optical fiber clamp 23 , the connector 22 and the electric control rotating table 21 are coaxial. In actual work, the optical fiber clamp 23 clamps one end of the multi-core optical fiber 5. Since the optical fiber clamp 23 is arranged on the plane of the crescent cylinder 221 of the connector 22, the cylinder 222 of the connector 22 is clamped on the electric control platform. Rotate the inside of the mounting hole so that when the electronically controlled rotating platform is opened, the rotating mechanism 2 can drive the multi-core optical fiber 5 to rotate. Generally, there is a centimeter-level gap between the end surface of the rotating mechanism 2 and the end surface of the adjacent placing platform 3 , that is, there is a centimeter-level gap between the end surface of the optical fiber holder 23 and the end surface of the adjacent placing platform 3 .

The rotating mechanism 2 provided in the embodiment of the present application adopts an electronically controlled rotating table 21, which can greatly improve the rotation accuracy, and then improve the positioning accuracy of the fiber core 51 of the multi-core optical fiber 5 during laser writing. The two ends of the rotating mechanism are clamped, and the clamping effect is good. The overall structure of the rotating mechanism 2 is simple and easy to operate, and the control accuracy is accurate.

Optionally, as shown in FIGS. 1-3 , the clamping device for laser direct writing of multi-core fiber Bragg gratings further includes a lifting mechanism 6 . One end of the lifting mechanism 6 is connected with any rotating mechanism 2 for driving the rotating mechanism 2 to lift. In practical applications, if the length of the multi-core optical fiber 5 is just consistent with the length of the optical fiber clamps 23 at both ends, then the multi-core optical fiber 5 can just be clamped by the optical fiber clamp 23, but generally the length of the multi-core optical fiber 5 will be relatively long, so that On the cylinder 222 of the connector 22 of the rotating mechanism 2, and on the end plate 12, a via hole is provided. The via hole is coaxial with the optical fiber clamp 23. After the hole passes through the via hole on the cylinder 222 of the connector 22 on this side, then passes through the mounting groove of the fiber holder 23 on this side and passes through the placement table 3, and then is clamped by the fiber holder 23 on the other side and After passing through the installation groove, pass through the via hole on the cylinder 222 of the connecting piece 22 on this side, and then pass through the via hole on the side end plate 12 . However, during installation, the multi-core optical fiber 5 needs to pass through two rotating mechanisms 2 , which greatly increases the difficulty of observing and aligning the multi-core optical fiber 5 . And one end of the lifting mechanism 6 of the present application is connected with any rotating mechanism 2, which can drive the connected rotating mechanism 2 to rise or fall a preset distance, such as 10cm, when the other end of the multi-core optical fiber 5 is held by the optical fiber clamp on the other side After 23 is fixed and clamped, the lifting mechanism 6 drives the rotating mechanism 2 connected to it to descend or rise the preset distance, so that the rotating mechanism 2 on this side returns to the original position, and clamps and fixes the multi-core optical fiber 5 at this end, thereby The installation difficulty of the multi-core optical fiber 5 is reduced, and the observation, installation and alignment of the multi-core optical fiber 5 are facilitated.

Specifically, the lifting mechanism 6 may include an electric push rod. Exemplarily, the end plate 12 on the left side in Figs. The upper end surface is fixed, and during the elongation process of the push-pull rod of the electric push rod, it can drive the electric control rotary table 21 to descend until the via hole on the end plate 12 is exposed. The right end of the multi-core optical fiber 5 is installed. Pulled to the inner side of the left end, in the process of shortening the push-pull rod of the electric push rod, it can drive the electric control rotary table 21 to rise, and then the left end of the multi-core optical fiber 5 is fixedly installed. Of course, at this time, a guide rail can be provided on the side of the end plate 12 close to the electric control turntable 21, and a chute matching the guide rail can be set on the side of the electric control turntable 21 close to the end plate 12, thereby ensuring that the electric control turntable 21 Steady lifting.

The clamping device for laser direct writing of multi-core fiber Bragg gratings provided by the embodiment of the present invention, as shown in FIGS. Both the placing plate 32 and the optical fiber focusing and placing assembly 33 are strip-shaped. The two ends of the placing plate 32 are respectively arranged on the two supporting platforms 13 , and a slit 31 penetrating from top to bottom is provided on it, and the upper side of the slit 31 is used for placing the optical fiber focusing and placing assembly 33 . As shown in FIGS. 4-7 , the optical fiber focusing assembly 33 includes a first glass substrate 331 , a second glass substrate 332 and a focusing medium 333 . A focusing medium 333 is arranged between the first glass substrate 331 and the second glass substrate 332 , and the focusing medium 333 is provided with a placement hole penetrating along its own axial direction, and the placement hole is used for installing the multi-core optical fiber 5 . The second glass substrate 332 rests on the upper side of the slit 31 . Wherein, the first glass substrate 331 is a piece of flat glass. The second glass substrate 332 plays a supporting role. The placement hole is generally cylindrical, so as to better fit the outer contour of the multi-core optical fiber 5 .

In practical applications, if the cross section of a simple optical fiber is observed with an optical microscope 8, it will be observed that the cross section is cylindrical and has a large spherical aberration, which causes the focused spot to become a long strip at the focal plane, which seriously affects the spacing of the Bragg gratings. In the placing table 3 provided by the embodiment of the present invention, the first glass substrate 331 and the focusing medium 333 in the optical fiber focusing and placing assembly 33 work together to realize the focusing of the laser beam 7 and completely eliminate cylindrical spherical aberration, so that the multi-core optical fiber 5 The laser spot of the optical fiber core 51 laser direct writing is circular.

In practical applications, the optical fiber focusing assembly 33 also includes a hollow glass tube 334 . The hollow glass tube 334 abuts between the first glass substrate 331 and the second glass substrate 332 , and the focusing medium 333 is disposed on the periphery of the hollow glass tube 334 and between the first glass substrate 331 and the second glass substrate 332 . The inner cavity of the hollow glass tube 334 is used for installing the multi-core optical fiber 5 , that is, the inner cavity of the hollow glass tube 334 is used as a placement hole for installing the multi-core optical fiber 5 . Firstly, since the hollow glass tube 334 has a relatively high hardness, it provides a supporting force for the multi-core optical fiber 5 and can avoid bending of the flexible multi-core optical fiber 5 caused by gravity, thereby improving the accuracy of laser writing. Secondly, when the focusing medium 333 is still soft after curing, the hollow glass tube 334 can provide a stable installation space for the multi-core optical fiber 5 and support the soft focusing medium 333 . When preparing the optical fiber focusing and placing assembly 33, the hollow glass tube 334 is placed on the second glass substrate 332, and then the focusing medium 333 is poured into the periphery of the glass substrate, and then the first glass substrate 331 is placed. After the focusing medium 333 is cured, that is A fiber focus placement assembly 33 is formed. The inner diameter of the hollow glass tube 334 is determined according to the outer diameter of the multi-core optical fiber 5 actually installed, and generally its inner diameter is slightly larger than the outer diameter of the multi-core optical fiber 5, so that air is formed between the multi-core optical fiber 5 and the hollow glass tube 334. The size of the air gap is on the order of microns, which is convenient for the insertion installation of the multi-core optical fiber 5 and the rotation of the multi-core optical fiber 5 .

As shown in Figures 4 to 7, the multi-core optical fiber 5 includes a coating, an outer cladding, an optical fiber cladding 52 and an optical fiber core 51. When the multi-core optical fiber 5 is installed, the coating and the outer cladding of the multi-core optical fiber 5 are removed. , leave the fiber cladding 52 and the fiber core 51, and pass them into the transparent glass tube.

Optionally, the focusing medium 333 includes a photosensitive adhesive or a refractive index matching liquid. Among them, the photosensitive adhesive is generally composed of a photosensitive resin, a sensitizer, a crosslinking agent, a photosensitizer, a stabilizer and a solution, and is generally used for bonding transparent materials. In this application, the laser can be focused on the fiber core 51 of the multi-core optical fiber 5 through the photosensitive adhesive, and the focusing effect is better. Further, the photosensitive adhesive can be optical glue. When preparing the optical fiber focus placement assembly 33, first place a cylinder for placing the hole shape on the second glass substrate 332, or when the clamping device includes a hollow glass tube 334, place the hollow glass tube 334 on the second glass substrate 332 Afterwards, between its periphery, the first glass substrate 331 and the second glass substrate 332, use a photosensitive adhesive such as optical glue to bond, and the lower surface of the first glass substrate 331 and the upper surface of the second glass substrate 332 remain parallel. Due to surface tension and capillary action of the photosensitive adhesive, the periphery of the cylinder (or hollow glass tube 334) and the gap between the two glass plates will be filled. After the photosensitive adhesive is cured, a transparent focusing medium 333 is formed to facilitate laser focusing.

In various optical-related inspections, a refractive index matching liquid is generally added between two optical devices to eliminate the influence of the joint interface on the optical performance. In this application, the refractive index matching liquid can be used to focus the laser light on the fiber core 51 of the multi-core optical fiber 5, and the focusing effect is good. Further, the refractive index matching liquid can be paraffin.

As shown in Figure 4, the upper surface of the second glass substrate 332 is a plane, or as shown in Figure 5, the upper surface of the second glass substrate 332 is concave to form a cuboid through groove, or as shown in Figure 6, the second glass substrate The upper surface of 332 is concave to form a triangular prism through groove.

When the upper surface of the second glass substrate 332 is flat, that is, it is flat glass with the first glass substrate 331 , the shape and structure are consistent, which can facilitate the preparation of the optical fiber focusing assembly 33 .

When the upper surface of the second glass substrate 332 is concave to form a cuboid through groove, when preparing the optical fiber focusing and placing assembly 33, it is convenient to put the focusing medium 333 in, and there is no need to worry that the fluid focusing medium 333 poured in the initial stage will flow around. At the same time, the shape of the cured focusing medium 333 is a cuboid with a fixed shape, so that the focusing effect of the focusing medium 333 is better. Certainly, on the cross section perpendicular to the axis of the second glass substrate 332 , the cross section of the cuboid through groove can be rectangular or square. FIG. 5 shows a schematic structural diagram of the rectangular parallelepiped through groove.

When the upper surface of the second glass substrate 332 is concave to form a triangular prism through groove, that is, on the cross section perpendicular to the axis of the second glass substrate 332, the cross section of the triangular prism through groove is a triangle, and the plane where one side of the triangle is located A first glass substrate 331 is provided. Similarly, when preparing the optical fiber placement assembly, it is convenient to put in the focusing medium 333, without worrying that the fluid focusing medium 333 poured in the initial stage will flow around, and the shape of the cured focusing medium 333 is a triangular prism, and the shape is fixed. The focusing effect of the focusing medium 333 is better. In addition, the two inner wall surfaces of the triangular prism channel and the lower surface of the first glass substrate 331, these three planes can provide the hollow glass tube 334 with three mutually restrictive extrusion forces, so that the hollow glass tube 334 can be installed The latter is more stable, so that the multi-core optical fiber 5 installed in its inner cavity is more stable.

Referring to FIGS. 1 to 3 , the clamping device for multi-core fiber Bragg grating laser direct writing provided by the embodiment of the present invention, the placing table 3 also includes a first elastic member and a first micro-adjustment rod 34 . One end of the placement platform 3 is fixed with a supporting platform 13 . Another supporting platform 13 includes a bottom plate 131 , one end of the bottom plate 131 is connected to the fixed plate 11 , and a first through hole is arranged on the bottom plate 131 , and the axis of the first through hole is perpendicular to the top surface of the bottom plate 131 . The front end of the first fine adjustment rod 34 passes through the first through hole and abuts against the bottom surface of the supporting platform 13 . The first elastic member is disposed between the top surface of the bottom plate 131 and the bottom surface of the placing platform 3 (the first elastic member is not shown in the figure). The first elastic member can be a compression spring or a rubber spring. After the multi-core optical fiber 5 is installed, in order to make laser writing more accurate, it is necessary to fine-tune the position of the placing table 3 to adjust the position of the multi-core optical fiber 5 . When the position of the placing table 3 needs to be adjusted downward, the first fine adjustment rod 34 moves downward, and when the position of the placing table 3 needs to be adjusted upward, the first fine adjustment rod 34 moves upward, and the first fine adjustment rod 34 moves upward. An elastic member can provide a stable push/pull force for the placing table 3, and cooperate with the first micro-adjustment lever 34 to make the adjustment of the upper and lower positions of the placing table 3 more precise.

And/or, the placing table 3 further includes a second elastic member and a second fine adjustment rod 35 . That is, the placement table 3 can only include the first elastic member and the first micro-motion adjustment rod 34, can only include the second elastic member and the second micro-motion adjustment rod 35, or can also include the first elastic member, the first micro-motion adjustment rod 35, and the first elastic member and the first micro-motion adjustment rod. The adjustment rod 34 , the second elastic member and the second fine movement adjustment rod 35 . Of course, when the placement table 3 includes the first elastic member, the first fine adjustment rod 34, the second elastic member and the second fine adjustment rod 35, the simultaneous adjustment of the placement table 3 along the Y-axis and the Z-axis direction can be realized, Adjustment works best.

Another supporting platform 13 also includes a side plate 132, that is, another supporting platform 13 is L-shaped. The side plate 132 is provided with a second through hole, and the axis of the second through hole is perpendicular to the side surface of the side plate 132 . The front end of the second fine adjustment rod 35 passes through the second through hole and abuts against the first side surface of the supporting platform 13 . The second elastic member is disposed between the fixing plate 11 and the second side of the support platform 13 , or between the first side and the side plate 132 (the second elastic member is not shown in the figure). Wherein the first side and the second side are two opposite sides of the supporting platform 13 . The second elastic member can be a compression spring or a rubber spring. When it is necessary to adjust the placing table 3 to the direction away from the fixed plate 11 of the fixed frame 1, the first micro-adjustment lever 34 moves outwards; A micro-adjustment rod 34 moves inward, and the second elastic member can provide a stable push/pull force for the placement table 3, and cooperate with the second micro-adjustment rod 35 to make the adjustment of the inner and outer positions of the placement table 3 more accurate.

Wherein, the first through hole and the second through hole can be screw holes, and the outer walls of the first inching adjustment rod 34 and the second inching adjustment rod 35 are provided with external threads, and the screw holes and the threads work together, which can be more convenient and fast 1. Adjust the position of the placement table 3 accurately.

The various implementations in this specification are described in a progressive manner, the same or similar parts of the various implementations can be referred to each other, and each implementation focuses on the differences from other implementations.

The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be described in the foregoing embodiments Modifications to the technical solutions, or equivalent replacement of some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the present application.

Claims (8)

1. A clamping device for multi-core fiber Bragg grating laser direct writing is characterized by comprising a fixed frame, a rotating mechanism and a placing table;

the fixing frame comprises a fixing plate, two end plates and two supporting tables; two ends of the fixed plate are respectively provided with an end plate, and the surface of each end plate is vertical to the surface of the fixed plate, so that a placing space is formed inside the fixed frame; the two support tables are positioned in the placing space, and one ends of the two support tables are fixed with the fixed plate;

one side of the fixing plate, which is far away from the placing space, is arranged on the three-dimensional movement mechanism;

the multi-core optical fiber placing platform is long-strip-shaped, two ends of the placing platform are respectively arranged on the two supporting platforms, the placing platform is provided with a slit which penetrates through the placing platform from top to bottom, the multi-core optical fiber is placed at the position of the slit, and the extending direction of the multi-core optical fiber is parallel to the length direction of the placing platform;

the two end plates are provided with one rotating mechanism at one side close to the placing space, and the rotating mechanisms are used for clamping two ends of the multi-core optical fiber and can drive the multi-core optical fiber to rotate along the axis of the multi-core optical fiber.

2. The clamping device for multi-core fiber bragg grating laser direct writing according to claim 1, wherein the rotating mechanism comprises an electrically controlled rotating table, a connecting piece and a fiber clamp;

the electric control rotating platform is fixed with the end plate;

the connecting piece comprises a cylinder and a crescent cylinder; one end of the crescent cylinder is connected with the end face of the cylinder, and the plane faces to the axis of the cylinder; the outer wall of the cylinder is clamped in the rotary mounting hole of the electric control rotary table;

the optical fiber clamp is arranged on the plane of the crescent cylinder and used for clamping one end of the multi-core optical fiber, and the optical fiber clamp, the connecting piece and the electric control rotating platform are coaxial.

3. The clamping device for multi-core fiber Bragg grating laser direct writing as claimed in claim 1, further comprising a lifting mechanism;

one end of the lifting mechanism is connected with any one of the rotating mechanisms and used for driving the rotating mechanisms to lift.

4. The clamping device for the multi-core fiber Bragg grating laser direct writing as claimed in any one of claims 1 to 3, wherein the placing table comprises a placing plate and a fiber focusing placing component;

the placing plate and the optical fiber focusing placing assembly are both strip-shaped;

the two ends of the placing plate are respectively arranged on the two supporting tables, the placing plate is provided with a slit which penetrates through the supporting tables from top to bottom, and the upper side of the slit is used for placing the optical fiber focusing placing component;

the optical fiber focusing placement component comprises a first glass substrate, a second glass substrate and a focusing medium;

the focusing medium is arranged between the first glass substrate and the second glass substrate, the focusing medium is provided with a placing hole which penetrates through the focusing medium along the axial direction of the focusing medium, and the placing hole is used for installing the multi-core optical fiber; the second glass substrate rests on the upper side of the slit.

5. The clamping device for multicore fiber bragg grating laser direct write of claim 4, the fiber focus placement assembly further comprising a hollow glass tube;

the hollow glass tube is abutted between the first glass substrate and the second glass substrate, and the focusing medium is arranged at the periphery of the hollow glass tube and is positioned between the first glass substrate and the second glass substrate;

the inner cavity of the hollow glass tube is used for installing the multi-core optical fiber.

6. The clamping device for multi-core fiber Bragg grating laser direct writing of claim 4, wherein the focusing medium comprises a photosensitive adhesive or an index matching fluid.

7. The clamping device for multi-core fiber Bragg grating laser direct writing of claim 4, wherein the upper surface of the second glass substrate is a plane, or the upper surface is recessed to form a cuboid through groove, or the upper surface is recessed to form a triangular prism through groove.

8. The clamping device for the multi-core fiber Bragg grating laser direct writing according to any one of claims 1 to 3, wherein the placing table further comprises a first elastic member and a first micro-motion adjusting rod;

one end of the placing table is fixed with one supporting table;

the other supporting table comprises a bottom plate, one end of the bottom plate is connected with the fixing plate, a first through hole is formed in the bottom plate, and the axis of the first through hole is perpendicular to the top surface of the bottom plate;

the front end of the first inching adjusting rod penetrates through the first through hole and then abuts against the bottom surface of the supporting platform;

the first elastic piece is arranged between the top surface of the bottom plate and the bottom surface of the placing table;

and/or the placing table further comprises a second elastic piece and a second inching adjusting rod;

the other support table further comprises a side plate, the side plate is arranged at one end, away from the fixed plate, of the bottom plate, and the surface of the side plate is perpendicular to the top surface of the bottom plate;

the side plate is provided with a second through hole, and the axis of the second through hole is perpendicular to the side surface of the side plate;

the front end of the second inching adjusting rod penetrates through the second through hole and then abuts against the first side face of the supporting platform;

the second elastic element is arranged between the fixing plate and the second side surface of the supporting table or between the first side surface and the side plate.

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