JP2000275452A - Optical fiber machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber machining device capable of performing a grating machining for an optical fiber accurately over a relatively long range longer than 1 m, by controlling a machining stage, a mirror stage, a mask stage, and a measuring device. SOLUTION: A machining stage 10, a mask stage 20, and a mirror stage 30 are loaded on a stone surface plate, and this stone surface plate is installed on a vibration-elimination table. A measuring device 40 is loaded on the stone surface plate, which accurately measures a distance between an end of a fiber work 12 and an end of a mask based on their relative positions. The machining stage 10, the mask stage 20, and the mirror stage 30 respectively include driving systems, and these driving systems and the measuring device 40 are controlled by a control device. Especially, the machining stage 10 has a rough position adjusting function at μm level, and the mask stage 20 has a precise position adjusting function at nm level. Therefore, continuous machining at high accuracy is allowed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical fiber processing apparatus, and more particularly to an optical fiber processing apparatus for performing grating processing on an optical fiber.

[0002]

2. Description of the Related Art Recently, it has been proposed to provide an optical fiber called a temperature-independent long-period fiber grating by irradiating an optical fiber with laser light and performing grating processing. Briefly, the coating on the area forming the grating of the optical fiber is removed,
A grating is formed by irradiating a laser beam having a wavelength in the ultraviolet region for a certain period of time and performing this at intervals of one to several (μm), that is, at intervals of the grating period.

A processing apparatus for performing such grating processing holds an optical fiber by a holder mounted on a movable stage, fixes a laser irradiation section, and moves the holder on the movable stage by a small distance, that is, by the above-described distance. Laser irradiation is performed while moving intermittently.

[0004]

However, in the above-mentioned processing apparatus, the processing range is at most 10 (cm).
It is about. On the other hand, a processing range of about 1 (m) is actually required, and a processing apparatus that continuously performs such a processing range has not been provided.

It is an object of the present invention to provide an optical fiber processing apparatus capable of performing grating processing on an optical fiber with high accuracy over a relatively long range of 1 (m) or more.

[0006]

According to the present invention, there is provided an optical fiber processing apparatus for irradiating an optical fiber with processing laser light at predetermined intervals to perform grating processing, wherein the optical fiber is fixed. A work stage having a stroke of a work range length L1 and a mask of a predetermined length having a large number of transmission areas at the predetermined interval are mounted, and are movable on the work stage and finely adjusted in position. A mask stage having a mechanism, a mirror stage movable with the mask stage and having a movable mirror for scanning the processing laser beam with respect to the mask, and a mirror stage between the fiber work and the mask. A measuring device for accurately measuring the relative position of
The processing stage, the mask stage, a stone surface plate on which the mirror stage and the measuring device are mounted, and a control device for controlling the processing stage, the mirror stage, the mask stage and the measuring device. An optical fiber processing apparatus is provided.

As the mask stage, one having an accurate position adjustment function on the nanometer (nm) level is used, and as the measuring device, one having an accurate measurement function on the nanometer level is used.

In the grating processing, the control device roughly positions and fixes the processing stage at a predetermined position, and then positions the mask stage at a predetermined distance from the fiber work based on a measurement signal of the measuring device. Finely adjusting the position of the mask, and then moving the movable mirror to irradiate the processing laser light at the predetermined interval to the optical fiber through the mask, thereby grating the area corresponding to the length of the mask. Perform processing, and then move the processing stage with reference to the predetermined distance to roughly position the first transmission area of the mask so as to be at a predetermined distance from the last processed irradiation unit. Then, the mask stage is finely adjusted and precisely positioned, and then the movable mirror is moved to pass through the mask. Performed grating working in the area corresponding to the length of the mask by irradiating the processing laser light at the predetermined intervals in the optical fiber, or less,
By repeating the above operation, the grating processing of the processing range length L1 is continuously performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, the optical fiber processing apparatus is equipped with a fiber work 12 for fixing an optical fiber 11, a processing stage 10 having a stroke of a processing range length L1 in one axial direction (horizontal direction in FIG. 1), and a predetermined interval. Mask stage 2 having a predetermined length of mask having a large number of transmission areas, and movable on the processing stage 10 in the uniaxial direction and having a position fine adjustment mechanism.
0, and a mirror stage 30 which is movable together with the mask stage 20 in the uniaxial direction and has a movable mirror 31 mounted thereon for scanning the processing laser beam with respect to the mask. Here, the processing range length L1 is
About 1 (m) is assumed. Further, as described later, a mask having a length of about 10 (cm) is used.

The processing stage 10, the mask stage 20,
The mirror stage 30 is mounted on an unillustrated stone surface plate,
This stone surface plate is installed on a vibration isolation table. The stone surface plate also
A measuring device 40 for accurately measuring the distance between the end face of the fiber work 12 and the end face of the mask from the relative position thereof is mounted. The stone surface plate is further equipped with a laser light source 51 for generating a processing laser beam having an ultraviolet wavelength range. The processing laser beam from the laser light source 51 passes through reflection mirrors 52 and 53. To the movable mirror 31. The processing laser light incident on the movable mirror 31 changes its direction downward.

The mask stage 20 has a mask holder 21 as shown in FIG. The mask holder 21 has an opening 21a which is substantially the same as the length of the mask and is long in the uniaxial direction. The processing laser light directed downward by the movable mirror 31 is transferred to the movable mirror 3 that can move integrally with the movable mirror 31.
2 allows the orientation to be changed in the horizontal direction. The processing laser light whose direction has been changed in the horizontal direction is applied to the mask 22 held on the opposite side through the opening 21a. Mask 22
Is held on the mask holder 21 by the leaf spring 23.

As the mask 22, a diffraction grating is used.
This diffraction grating is structurally equivalent to one having a large number of transmission regions of the processing laser light at predetermined intervals in the length direction.
The optical fiber 11 is disposed on the left side of the mask 22 in FIG. 2, and the laser beam for processing is applied to the stripped portion of the optical fiber 11 from the side. Moreover, the movable mirrors 31 and 32
Is movable in the uniaxial direction by the length of the mask 22, and the movable mirror 31, with the optical fiber 11 fixed,
By moving the beam 32, the processing laser beam can be scanned through the mask 22 with respect to the optical fiber 11 at a predetermined interval.

A processing stage 10, a mask stage 20,
Each of the mirror stages 30 has a drive system, and the drive system and the measurement device 40 are controlled by a control device (not shown). In particular, a processing stage having a coarse position adjustment function of a μm (micrometer) level is used, and a mask stage 20 having a fine position adjustment function of a nm (nanometer) level is used. For this purpose, a measuring device 40 used for precise positioning of the mask stage 20 has a measuring function at the nm level.

The measuring device 40 measures the distance by utilizing the interference of light, and includes a laser interferometer light source 41, a reflecting mirror 42, a beam splitter 43, a reflecting mirror 44, a differential interferometer 45, and a wavelength tracker. 46. This type of measuring device 40 is well known, but will be briefly described with reference to FIG. The laser light from the laser interferometer light source 41 is
The light is branched, and one of the light is incident on a differential interferometer 45. Laser light is emitted from the differential interferometer 45 toward the end face of the fiber work 12 and the end face of the mask 22. A reflection mirror is provided on each of the end face of the fiber work 12 and the end face of the mask 22. As a result, the laser light reflected by the reflection mirror returns to the differential interferometer 45, from which an optical signal including an interference fringe component that changes according to the distance between the end face of the fiber work 12 and the end face of the mask 22 is output. Is done. This optical signal enters the receiver R1 via the optical fiber 47, is converted into an electric signal, and is output to the control unit 48. Receiver R
The electric signal from 1 is a signal corresponding to the distance between the end face of the fiber work 12 and the end face of the mask 22.

The wavelength tracker 46 receives the other of the two laser beams split by the beam splitter 43. The wavelength tracker 46 is for tracking changes in air reflectance caused by changes in ambient temperature and optically correcting environmental changes. In other words, the wavelength tracker 46 is for correcting a distance measurement error caused by a change in the ambient temperature. The optical signal from the wavelength tracker 46 enters the receiver R2 via the optical fiber 49 and is converted into an electric signal. The electric signal from the receiver R2 is
The control unit 48 corrects a signal indicating the distance from the receiver R1 based on the correction value, and outputs a measurement signal to the control device described above. As such a measuring device 40, one having a measuring function at the nm level in the uniaxial direction is provided.

In FIG. 3, the mask stage 20 is precisely positioned in the uniaxial direction by a precision positioning mechanism 25 using a piezo actuator. As such a precision positioning mechanism 25, a mechanism having a precision position adjustment function at the nm level is provided.

Next, referring to FIG. 5, the grating processing by the present processing apparatus will be described in order. FIG.
In FIG. 2, the mask 22 is equivalent to a mask having a plurality of laser light transmission areas 22a at predetermined intervals for convenience.

In FIG. 5 (a), when performing the grating processing, the control device first coarsely positions and fixes the processing stage 10. As a result, fiber work 1
The second end face (right end face) is set within a few μm of a predetermined position. This is because the processing stage 10 has a coarse position adjustment function at the μm level. The predetermined position is
It is set in advance.

Next, based on the measurement signal from the measuring device 40, the precision positioning mechanism 25 finely adjusts the mask stage 20 to a position at a predetermined distance from the processing stage 10 to perform precise positioning. Strictly speaking, the end face (right end face) of the mask 22 is separated from the end face of the fiber work 12 by a predetermined distance L1.
Precision positioning so that it is located only a distance away. This positioning accuracy is, as described above, an accurate positioning accuracy on the order of nm. In FIG. 5, arrows pointing toward the end face of the mask 22 and the end face of the fiber work 12 are laser beams from the differential interferometer 45 described with reference to FIG. The size from the right end face of the mask 22 to the rear edge of the last transmission area is defined as L2. During the positioning of the mask stage 20 by the fine positioning mechanism 25, the mirror stage 30 moves together.

After the positioning as described above, the mask stage 20 is fixed, and the movable mirrors 31 and 32 are moved in the uniaxial direction to move the optical fiber 11 through the mask 22.
By irradiating the laser light for processing at the above-mentioned predetermined intervals, the grating processing of the region corresponding to the length of the mask 22 is performed.

After the completion of the above grating processing, FIG.
As shown in (b), the mask stage 20 is fixed,
The processing stage 10 is moved with reference to the predetermined distance L1 to roughly position the first transmission area 22a-1 of the mask 22 so as to be at the predetermined distance from the last processed irradiation unit 11-1. . Processing stage 10 at this time
Is the structure of the mask 22, that is, the mask 2
2, the size from the end face to the leading edge of the first transmission area, the pitch (predetermined interval) of the transmission area, the above-mentioned size L2, and the like. Here, the size from the end face of the mask 22 to the leading edge of the first transmission area is equal to the pitch of the transmission area, and in this case, the movement amount LX = L2.

After the above-described rough positioning, the mask stage 20 is further finely adjusted by the fine positioning mechanism 25 to perform fine positioning, and the end face of the mask 22 is precisely positioned at (L1 + L2) from the end face of the fiber work 12. The positioning accuracy at this time is also at the nm level.

Subsequently, the mask stage 20 is fixed,
By moving the movable mirrors 31 and 32 and irradiating the optical fiber 11 with the processing laser light at the predetermined interval through the mask 22, grating processing is performed on a region corresponding to the length of the mask 22.

Hereinafter, by repeating the above operation,
The grating processing can be continuously performed over the stroke of the processing stage 10, here, the processing range length L1 of about 1 m. Of course, by increasing the stroke length of the processing stage 10, the processing range length L1 that can be continuously processed.
Can also be large.

As the precision determination mechanism 25, a mechanism using a magnetostrictive element can be used instead of a mechanism using a piezo actuator.

[0026]

As described above, according to the optical fiber processing apparatus of the present invention, a relatively long range (1 m or more) is required for the grating processing on the optical fiber.
Can be continuously processed with high precision.

[Brief description of the drawings]

FIG. 1 is a front view of an optical fiber processing apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of a main part of the mask stage in FIG. 1 as viewed from the direction of arrow A in FIG.

FIG. 3 is a side view of the periphery of the precision positioning mechanism of the mask stage in FIG. 1 as viewed from the direction of arrow A in FIG. 1;

FIG. 4 is a diagram showing a configuration of a measuring device in FIG.

FIG. 5 is a diagram showing a positional relationship between a mask and a fiber work in order to explain grating processing in the present invention.

[Explanation of symbols]

 Reference Signs List 10 processing stage 11 optical fiber 12 fiber work 20 mask stage 21 mask holder 22 mask 25 precision positioning mechanism 30 mirror stage 31, 32 movable mirror 40 measuring device 51 laser light source 52, 53 reflection mirror

Claims (4)

[Claims] An optical fiber processing apparatus for irradiating an optical fiber with a processing laser beam at a predetermined interval to perform grating processing, comprising: a fiber work for fixing the optical fiber;
A processing stage having a stroke of a processing range length L1, a mask stage mounted with a mask of a predetermined length having a large number of transmission areas at the predetermined interval, and movable on the processing stage and having a position fine adjustment mechanism; A mirror stage movable with a mask stage and equipped with a movable mirror for scanning the processing laser light with respect to the mask; and accurately measuring a relative position between the fiber work and the mask. A measuring device; a stone surface plate on which the processing stage, the mask stage, the mirror stage and the measuring device are mounted; and a control for controlling the processing stage, the mirror stage, the mask stage and the measuring device. An optical fiber processing apparatus provided with an apparatus. 2. An optical fiber processing apparatus according to claim 1, wherein said mask stage has a function of adjusting a precise position on a nanometer level. 3. An optical fiber processing apparatus according to claim 1, wherein said measuring apparatus has a precision measuring function of nm level. 4. The optical fiber processing device according to claim 1, wherein the control device is configured to perform
The processing stage is roughly positioned and fixed at a predetermined position, and then the mask stage is finely adjusted to a position at a predetermined distance from the fiber work based on a measurement signal of the measuring device, and then the mask stage is precisely positioned. The movable mirror is moved to irradiate the processing laser light to the optical fiber through the mask at the predetermined interval, thereby performing grating processing in a region corresponding to the length of the mask, and then, with reference to the predetermined distance. As the processing stage is moved, the first transmission area of the mask is roughly positioned so as to be located at the predetermined interval from the last processed irradiation part, and the mask stage is finely adjusted to be precise. Positioning, then moving the movable mirror and irradiating the processing laser light at the predetermined interval to the optical fiber through the mask Performed grating working in the area corresponding to the length of the mask by Rukoto, below, an optical fiber processing apparatus characterized by continuously performing grating machining of the machining area length L1 by repeating the above operation.