JPH08129111A - Apparatus for production of optical fiber type polarizer - Google Patents

Abstract

PURPOSE: To realize an optical fiber type polarizer with which loss characteristics stable to disturbance are obtainable. CONSTITUTION: This apparatus for producing the optical fiber type polarizer removes the initial twist possessed by an optical fiber 11 let off from a drum 14 by a twist removing part 20. The two points of the optical fiber 11 are held by a pulling-in roller 21 and a feed roller 23 and the optical fiber 11 is slackened by a tensionless part 22 between both rollers 21 and 23. The optical fiber 11 from which the twist is removed by its own elasticity by loosening the fiber is wound in alignment on the bobbin 12. As a result, the occurrence of the loss fluctuation of the transmitted light of the polarizer by the twist of the fiber 11 is prevented. The optical fiber type polarizer with which the stable loss characteristics are obtainable is thus realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-type polarizer manufacturing apparatus which obtains polarization characteristics by utilizing a difference in attenuation factor between two orthogonal polarizations when a birefringent optical fiber is bent. . Such a fiber-type polarizer is used in various optical fiber sensors such as an optical fiber gyro and an optical fiber hydrophone.

[0002]

2. Description of the Related Art In recent years, practical applications of coherent optical communication, optical fiber sensors and the like have been advanced, and the use of polarization control type devices has become an important issue. The polarization control type device has conventionally been composed of a bulk type element, but it is necessary to realize the optical fiber element in order to make the best use of the characteristics of the optical fiber system, and the development thereof is in progress.

One type of optical fiber device is a fiber type polarizer. A polarizer is one that extracts only one of the two linearly polarized light beams that are generally orthogonal to each other, and a birefringent prism or the like has been conventionally used. The fiber type polarizer realizes this function by a single optical fiber. FIG. 3 shows the structure of a fiber-type polarizer that has been conventionally proposed. In this polarizer 10, a birefringent optical fiber 11 (called a PANDA optical fiber, a Bow-tie optical fiber, an elliptical jacket optical fiber, an elliptic core optical fiber, etc.) is wound around a polarizer bobbin 12, and an adhesive 13 or the like is used. The optical fiber core is fixed by the method described above, and an anisotropic stress is applied to the core portion of the optical fiber to give a difference in attenuation rate between the two orthogonal polarizations.

A typical wavelength characteristic of this fiber type polarizer 10 is shown in FIG. The rise of the attenuation characteristics of Y-polarized light starts from a short wavelength, and the rise of the attenuation characteristics of X-polarized light starts from a long wavelength.
, Y polarized light shows a very large loss, and X polarized light is transmitted. Therefore, it is possible to obtain a single polarized light regardless of the polarization state of the incident light. Such a fiber type polarizer 1
When 0 is used, it can be easily coupled with other optical fibers and has a small coupling loss, and the transmitted wave (X polarized light in the above example)
Has a small insertion loss and is used, for example, in an optical fiber gyro.

By the way, the fiber type polarizer 10 is
Conventionally, it is manufactured as follows. FIG. 5 schematically shows a conventional fiber-type polarizer manufacturing apparatus. Referring to FIG. 5, the birefringent optical fiber 11 is wound around the optical fiber supply drum 14 in advance. The birefringent optical fiber 11 fed from the optical fiber supply drum 14 is guided by a guide roller 16 and tensioned by a tension pulley 15, and is wound around a polarizer bobbin 12. The reason why the birefringent optical fiber 11 is wound by applying tension is that the birefringent optical fiber 11 is alignedly wound on the polarizer bobbin 12 without causing bending or bending. In this way, the fiber-type polarizer 10 is manufactured.

[0006]

However, in the conventional manufacturing apparatus, when the polarizer bobbin 12 is aligned and wound, the bending and bending of the optical fiber 11 are removed, but the twist is not removed. It was sometimes wound around the polarizer bobbin 12 as it was. The optical fiber type polarizer 10 is
Since the difference in the frequency characteristics of the loss between the two orthogonal polarization components propagating in the optical fiber is utilized, if the birefringent optical fiber 11 is excessively twisted, the loss fluctuation of the transmitted light is easy. Will occur. Therefore, if the birefringent optical fiber 11 is wound around the polarizer bobbin 12 in a twisted state, the characteristics as a polarizer become unstable, and the loss characteristics are changed by even a small disturbance, and the reliability of the product is improved. There's a problem.

Therefore, an object of the present invention is to provide an optical fiber type polarizer manufacturing apparatus capable of eliminating the twist of the optical fiber when wound around the polarizer bobbin and realizing an optical fiber type polarizer having stable characteristics. It is to be.

[0008]

An optical fiber type polarizer manufacturing apparatus according to the present invention applies tension to a birefringent optical fiber fed from an optical fiber supply means, and the above birefringence is applied in a state where the tension is applied. In an optical fiber type polarizer manufacturing apparatus in which an optical fiber is wound around a polarizer bobbin, the birefringent optical fiber fed from the optical fiber supply means is loosened to remove the initial twist of the birefringent optical fiber in advance. It is characterized in that a twist removing portion is provided.

[0009]

According to the optical fiber type polarizer manufacturing apparatus of the present invention, the birefringent optical fiber is fed from the optical fiber supply means. The extended birefringent optical fiber is slackened by the twist removing portion to be in a tensionless state. In the birefringent optical fiber in the tensionless state, the restoring force due to the elasticity of the birefringent optical fiber itself removes the twist generated in the birefringent optical fiber in advance. Then, the birefringent optical fiber from which the twist is removed is applied with a predetermined tension and wound around the polarizer bobbin in an aligned manner.

[0010]

Embodiments will be described in detail below with reference to the accompanying drawings showing embodiments. FIG. 1 is a diagram schematically showing an optical fiber type polarizer manufacturing apparatus according to an embodiment of the present invention. Note that FIG.
The same parts as those of the conventional optical fiber type polarizer manufacturing apparatus shown in are denoted by the same reference numerals.

Referring to FIG. 1, this optical fiber type polarizer manufacturing apparatus includes an optical fiber supply drum 14 (hereinafter simply referred to as drum 14 in the embodiment) as an optical fiber supply means, and a twist remover 20. And the tension applying section 3
0 and a polarizer bobbin 12 are provided. The drum 14 has a cylindrical shape in which the long birefringent optical fiber 11 is wound in advance, and is rotatably supported by the central shaft 14a.

The twist remover 20 comprises a pair of pull-in rollers 21, a tensionless portion 22, and a pair of feed rollers 23. The pair of the pull-in roller 21 and the feed roller 23 are respectively provided with a predetermined pressing force and the birefringent optical fiber
1 (hereinafter, simply referred to as an optical fiber 11 in the embodiments)
And the optical fiber 11 has the rollers 21 and
It is clamped without slipping on 3

The pull-in roller 21 includes a cylindrical roller body 21a made of an elastic material such as rubber and a central shaft 21b.
The roller body 21a is rotatably supported about the central axis 21b. The feed roller 23 has the same configuration as that of the pull-in roller 21, and includes a cylindrical roller body 23a made of an elastic material such as rubber and a central shaft 23b.
And have. The roller bodies 21a and 23a
Have the same outer diameter, and the roller bodies 21a and 23a are rotated at the same rotation speed.
However, as long as the linear velocity of the optical fiber 11 is the same, the outer diameters and the number of rotations of the roller bodies 21a and 23a do not matter.

The tension-free portion 22 is an area in which the optical fiber 11 is slackened between the pull-in roller 21 and the feed roller 23 to be in a tension-free state. The tension applying section 30 applies a tension to the optical fiber 11 sent from the feed roller 23 of the twist removing section 20, and the first guide roller 3
1, a second guide roller 32, and a tension pulley 33. The first guide roller 31 and the second guide roller 32 are rotatably supported by central shafts 31a and 32a, respectively. The tension pulley 33 has a pulley body 33a, a pulley shaft 33b, a pulley bracket 33c, and a coil spring 33d, and the pulley body 33a is connected to the pulley bracket 3 by the pulley shaft 33b.
It is rotatably supported with respect to 3c. The pulley bracket 33c is attached to a predetermined position of the manufacturing apparatus of the optical fiber type polarizer 10, and the coil spring 33d.
The pulley bracket 33c is pulled by. The optical fiber 11 guided by the first guide roller 31
Is hung on the pulley main body 33a and then sent to the polarizer bobbin 12 in a state where tension is applied through the second guide roller 32.

The polarizer bobbin 12 is for winding the optical fiber 11 and is rotatably supported by the central shaft 12a. Next, the operation of this optical fiber type polarizer manufacturing apparatus will be described. The optical fiber 11 delivered from the drum 14 is sandwiched by the draw-in roller 21 and drawn in by the frictional force due to the pressing force of the roller. Then, it is sent to the tensionless portion 22.

In the non-tensioned portion 22, the optical fiber 11 is sufficiently loosened to remove the tension applied to the optical fiber 11. The pull-in roller 21 and the feed roller 23 are rotated at the same rotational speed, and the optical fiber 1 is not connected between the pull-in roller 21 portion and the feed roller 23 portion.
The linear velocities of 1 are equal. Therefore, the tensionless portion 22
Then, the optical fiber 11 can always hold a certain amount of slack. Then, in the optical fiber 11 in the tensionless state, even if the optical fiber 11 is twisted in advance, the twist is restored by the restoring force due to the elasticity of the optical fiber 11 itself. That is, the twist is removed. Since the optical fiber 11 is held by the roller body 23a of the feed roller 23 without slippage, the twist is not transmitted to the outside of the tensionless portion 22.
The optical fiber 11 from which the twist is removed is fed by the feed roller 23.
Is clamped by a predetermined pressing force by the tension applying portion 3
Sent to 0.

In the tension applying section 30, the first guide roller 31
The optical fiber 11 guided by is stretched around the tension pulley 33, and tension is applied by the tensile force of the coil spring 33d. Then, the optical fiber 11 to which the tension is applied by the second guide roller 32 causes the polarizer bobbin 1 to move.
2 and is aligned and wound on the polarizer bobbin 12. The optical fiber 11 wound around the polarizer bobbin 12 has an anisotropic stress applied to the core portion of the optical fiber 11. As a result, the optical fiber type polarizer 10 in which the attenuation rate difference is given between the two orthogonal polarizations is manufactured.

According to this embodiment, the optical fiber 11 is loosened by the tension-free portion 22 of the twist removing portion 20, and the twist is removed by the restoring force of the optical fiber 11 itself. Therefore, since the twist is removed, the wound film is wound around the polarizer bobbin 12, so that the aligned winding can be surely performed. As a result, it is possible to prevent the loss variation of the transmitted light of the optical fiber type polarizer 10 due to being wound around the polarizer bobbin 12 in a twisted state, and to obtain a stable loss characteristic. Can be realized.

Further, the friction coefficient of the pull-in roller 21 and the feed roller 23 is large, and the optical fiber 11 is sandwiched between the rollers 21 and 23 without causing slippage.
The twist of the optical fiber 11 is not transmitted to the outside of the twist remover 20. By the way, in the above embodiment,
When the optical fiber 11 is twisted and wound around the drum 14 in the same direction, the twist of the optical fiber 11 is removed by accumulating the twist in the twist removing portion 22. Therefore, if a certain amount of twist is accumulated in the twist removing portion 22, the twist removing ability of the twist removing portion 22 is reduced, but if maintenance is performed to release the accumulated twist at predetermined intervals, the twist removing portion 22 will be twisted. The removal ability can be restored. As a maintenance method, the optical fiber 11 sandwiched by the feed roller 23 may be opened, and the optical fiber 11 suspended on the tension applying section 30 may be removed to release the accumulated twist. Further, the length of the optical fiber 11 that is loosened by the twist removing portion 22 is more efficient because the twist removing capability can be improved and the frequency of the above maintenance is reduced.

The present invention is not limited to the above embodiment, since the twist removing section 20 removes the twist, the tension applying means 30 again causes the optical fiber 11 to move.
Even if no tension is applied to the birefringent optical fiber 11, the birefringent optical fiber 11 can be wound around the polarizer bobbin 12 only by the tension generated by the pressing force of the feed roller 23. Therefore, the tension applying means 30 may be omitted.

FIG. 2 is a view of the optical fiber type polarizer manufacturing apparatus as viewed from above. As shown in this FIG.
The drum 14 may be reciprocated as shown by the arrow. That is, when the drum 14 rotates once, the drum 14 is reciprocated at a speed at which the drum 14 moves by a distance equal to the winding pitch of the optical fiber 11 wound around the drum 14. By doing so, the path line of the optical fiber 11 from the drum 14 to the polarizer bobbin 12 is always in a straight line, and the generation of twist is more effectively suppressed, and the optical fiber 11 is wound in alignment with the polarizer bobbin 12. be able to.

Further, the drawing roller 21 and the feeding roller 2
Each of the roller main bodies 21a and 23a of No. 3 does not have to be an elastic body such as rubber, but has a large friction coefficient with respect to the birefringent optical fiber 11 and can hold the birefringent optical fiber 11 without slippage It can be one. In addition, various design changes can be made without changing the gist of the present invention.

[0023]

According to the present invention, after the initial twist generated in the birefringent optical fiber is removed in advance by the twist removing means, the winding is surely aligned and wound around the polarizer bobbin.
It is possible to prevent the loss variation of the transmitted light of the polarizer from being caused by being wound around the polarizer bobbin in a twisted state.

As a result, it is possible to provide an optical fiber type polarizer manufacturing apparatus which can realize an optical fiber type polarizer which can obtain stable loss characteristics.

[Brief description of drawings]

FIG. 1 is a schematic view of an optical fiber type polarizer manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a view of an optical fiber type polarizer manufacturing apparatus as viewed from above.

FIG. 3 is an external perspective view of a fiber type polarizer.

FIG. 4 is a graph showing typical wavelength characteristics of a fiber-type polarizer.

FIG. 5 is a schematic view of a conventional optical fiber type polarizer manufacturing apparatus.

[Explanation of symbols]

 10 Fiber Type Polarizer 11 Birefringent Optical Fiber 12 Polarizer Bobbin 14 Optical Fiber Supply Drum 20 Twist Remover

Claims (1)

[Claims] 1. An apparatus for producing an optical fiber type polarizer, wherein tension is applied to a birefringent optical fiber fed from an optical fiber supply means, and the birefringent optical fiber is wound around a polarizer bobbin with the tension applied. An optical fiber type polarizer characterized in that a twist removing section for removing an initial twist of the birefringent optical fiber is provided in advance by loosening the birefringent optical fiber fed from the optical fiber supply means. Manufacturing equipment.