JPH0714403U - Fixed parts for optical elements and optical isolators using the same - Google Patents

Abstract

(57) [Summary] [Object] To provide an optical element fixing component that is easy to bond to an optical element with a narrow bonding margin, and an optical isolator that has a small bonding margin for the optical element and is economical and easy to manufacture. The purpose is to do. The fixing part of the present invention is a fixing part 9 having a concave portion 7 into which a rectangular polarizer 3 is fitted, and a circular optical path 5 is opened in the concave portion 7, and the concave portion 7 has a corner portion. An escape portion 8 is provided in the. The optical isolator of the present invention uses such a fixing part 9 to fit the polarizer 3 into the recess 7 and join the corner 10 of the polarizer 3 and the corner of the recess 7 with a bonding agent. The bottom surface of the recess of the fixed component 9 is inclined with respect to the optical path,
It is more preferable that the polarizer 3 is closely attached to the bottom surface thereof.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fixing component for fixing an optical element in an optical communication path at a predetermined position, and an optical isolator to which the fixing component is applied.

[0002]

[Prior art]

 In optical communication systems and optical measuring instruments, various optical elements such as polarizers and analyzers are used as communication media. These optical elements are used as components of intermediate parts such as optical isolators.

An optical isolator is provided in an optical transmission line, and is used in the case of transmitting only the transmission light traveling in a predetermined transmission direction and selectively blocking the return light traveling to the light source. The transmitted light that oscillates from the laser light source may be reflected by the incident surface of the optical fiber, and the reflected return light may reach the laser light source. The return light that reaches the laser light source disturbs the light emitting function of the light source and causes noise. The optical isolator rotates the plane of polarization of light each time it passes, selects the difference in the traveling direction by the tilt of the rotated plane of polarization, and selectively blocks the return light.

As shown in a sectional view of FIG. 5, for example, the optical isolator is provided with a Faraday rotator 2 inside a cylindrical magnet 1 having openings at both ends, and a polarizer 3 and an analyzer 4 on both sides. The polarization directions of the transmitted light of the polarizer 3 and the analyzer 4 are relatively shifted by 45 degrees. The Faraday rotator 2 rotates the polarization direction of transmitted light by 45 degrees. The transmitted light A emitted from the light source is polarized by the polarizer 3, the plane of polarization is rotated by 45 degrees by the Faraday rotator 2, and the analyzer 4 is rotated with the plane of polarization inclined by 45 degrees with respect to the polarization direction of the polarizer 3. Through. When the transmitted light A is reflected by the end face of the optical fiber on the light receiving side, the return light B is slightly attenuated by the analyzer 4 and is transmitted, and the Faraday rotator 2 rotates the polarization plane again by 45 degrees. Since the return light B rotates the polarization plane by 90 degrees in the round trip path, the direction of the polarization plane of the return light B and the transmission polarization direction of the polarizer 3 are orthogonal to each other, and the return light B travels further straight by the polarizer 3. Is blocked.

The optical path 5 is formed in a circular shape. The incident surface of the optical elements such as the polarizer 3 and the analyzer 4 is formed to be slightly larger than the opening area of the optical path 5, and the outer peripheral portion protruding from the opening edge of the circular optical path 5 is a fixed part as shown in FIG. It becomes the joining margin 6 for 9, and is fixed with a joining agent such as an adhesive, low melting point glass, or solder. Optical elements such as polarizers are extremely expensive, and economically demanding miniaturization. The extra joining margin 6 should be as narrow as possible. However, if the joining margin 6 is narrowed, the adhesive strength of the joining agent becomes weaker accordingly. If the bonding margin 6 is narrow, the entire amount of the bonding agent cannot be retained in the bonding margin 6, and a part of the bonding agent may stick out inside from the opening edge of the optical path 5. If a part of the bonding agent protrudes from the opening edge of the optical path 5, a part of the optical path 5 is blocked and the optical path width becomes narrow. If the transmitted light A is diffusely reflected by the protruding adhesive, a part of it is also added to the return light B. It is very difficult to bond the optical element with the bonding margin 6 narrowed to the fixed component 9 while preventing the adhesive from protruding to the optical path 5 side.

[0006]

[Problems to be solved by the device]

 The present invention has been made to solve the above-mentioned problems, and it is a fixed part that can be easily joined to an optical element with a narrow joint margin, and a small joint margin for an optical element, which is economical and easy to manufacture. An object is to provide an optical isolator.

[0007]

[Means for Solving the Problems]

 A fixing part of the present invention and an optical isolator using the same, which has been made to achieve the above object, will be described with reference to the drawings corresponding to the embodiments.

The fixed part of the present invention is a fixed part 9 having a recess 7 into which a rectangular optical element 3 is fitted as shown in FIG. 1, and an optical path 5 is opened in the recess 7. The recess 7 is provided with a relief 8 at the corner.

In the optical isolator of the present invention, as shown in FIG. 5, a plurality of optical elements 2, 3 and 4 are arranged, transmission light A and return light B which are transmitted are selected, and the progress of the return light B is selectively made. The optical element 3 has a rectangular shape, and the fixed component 9 of the optical element 3 has a concave portion 7 into which the optical element 3 is fitted, and the optical path 5 is opened in the concave portion 7. 7 is provided with a relief portion 8 at the corner, and the corners of the optical element 3 and the fixed component 9 are bonded together with a bonding agent.

In this optical isolator, it is preferable that the bottom surface of the concave portion 7 is inclined with respect to the optical path direction, the optical element 3 is in close contact with the bottom surface, and the incident surface is inclined with respect to the optical path direction.

[0011]

[Action]

 In the fixed part or optical isolator of the present invention, the optical element 3 is rectangular, and the optical element 3 is fitted into the recess 7 of the fixed part 9 so that the corner 10 of the optical element 3 and the corner of the recessed part 7 of the fixed part 9 are connected. To join. Since the escape portion 8 is formed at the position where the bonding agent 11 is introduced, it is easy to determine the aim of the bonding position when bonding. The joints are limited to the corners, and the joint range is narrower than when the entire peripheral edge of the optical element 3 is annularly joined, but the joints are arranged on the peripheral edge of the optical element 3 at a distance and on average. Therefore, the joint is easily strengthened. Moreover, since the bonding range is narrow, the width of the bonding margin of the optical element 3 is minimized.

An escape portion 8 is formed at the corner of the recess 7. The escape portion 8 is located at the corner of the concave portion 7 and far from the opening edge of the optical path 5, and when the amount of the bonding agent 11 is excessive, the escape portion 8 stays as an escape area for the bonding agent 11, and the bonding agent 11 Is unlikely to protrude to the optical path 5 side. The shape of the escape portion 8 may be fan-shaped as shown in FIG. 1 or box-shaped as shown in FIG. It may be slit as shown in FIG. Both have similar effects.

[0013]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail.

FIG. 1 is a sectional view of an optical element fixing part of the present invention, and FIG. 5 is an embodiment of an optical isolator of the present invention using the same.

In the optical isolator of FIG. 5, a Faraday rotator 2 is provided in a cylindrical magnet 1 having openings at both ends, and a polarizer 3 and an analyzer 4 are provided on both sides of the Faraday rotator 2. The polarizer 3 is fixed to a fixed part 9 at a corner 10 and is housed in a tubular case body 12 together with the Faraday rotator 2 in the tubular magnet 1.

The polarizer 3, which is an optical element, is formed of a rectangular transparent plate. As shown in FIG. 1, a fixed component 9 for fixing the polarizer 3 has a concave portion 7 on its end face, and a circular optical path 5 is opened inside the concave portion 7. The concave portion 7 has a rectangular shape like the polarizer 3, and the relief portions 8 having a radius of 0.05 mm or more are formed in a fan shape at the four corners thereof. The polarizer 3 is fitted in the recess 7 of the fixed component 9, and the four corners of the polarizer 3 are joined together with a bonding agent.

The material of the fixed part 9 may be made of metal or heat-resistant resin. If it is used in large numbers, it can be manufactured by cutting, but if it has to be mass-produced, injection molding using a mold is suitable because the shape is relatively complicated.

The bonding agent 11 for bonding the fixed component 9 and the polarizer 3 may be solder or adhesive. Low melting point glass may be used. As shown in FIG. 1, for example, as shown in FIG. 1, a solder thin film 11a is formed in advance on the clearance 8 and a solder thin film 11b is also formed on the corresponding corner 10 of the polarizer 3 to form a polarized light in the recess 7. It is preferable to insert the element 3 and apply heat above the melting point of the solder to the corner 10 of the polarizer 3. Even if the solder is a little excessive, the surplus is retained in the escape portion 8 as shown in FIG. If the positions of the solder thin films 11a and 11b are separated from the opening of the optical path 5 as much as possible, the solder is further prevented from protruding to the edge of the opening. An adhesive may be formed in advance on the escape portion 8, and the polarizer 3 may be fitted onto the escape portion 8 and bonded to the fixed component 9. It is also possible to fit the optical element in the recess 7 in advance and then pour the adhesive into the clearance 8.

The analyzer 4 has the same shape as the fixed component 9 of the polarizer 3 and is fixed in the same manner as the polarizer 3 by a separate fixed component 9. Further, the Faraday rotator 2 may be fixed to the similar fixed component 9 and inserted into the cylindrical magnet 1.

Such an optical isolator selectively separates the transmitted light A and the return light B that are transmitted, and selectively blocks the progress of the return light. Even if the solder 11 or the adhesive for joining the polarizer 3 to the fixed component 9 is used excessively, the excess is retained in the escape portion 8 as it is, and the width of the optical path 5 is not narrowed. At the time of joining, the position where the solder 11 or the adhesive or the like is injected is clear, and even if the amount of injection is too large, the assembly is easy.

FIG. 4 shows a fixing part used in a second embodiment of the isolator of the present invention. The bottom surface of the recess 7 of the fixing component 9 is inclined with respect to the direction of the optical path. When the polarizer 3 is in close contact with the bottom surface of the fixed component 9, the incident surface is inclined with respect to the optical path direction.

An antireflection film is applied to the surface of the polarizer 3 or the analyzer 4 which constitutes the optical isolator or the like. The antireflection film is thin and cannot completely prevent the reflected light generated on the surface of the polarizer 3. Residual reflection of about 0.2% is unavoidable, and there is a concern that these reflected lights will add to the returning light B and return to the laser light source. If the surface of the polarizer 3 is tilted with respect to the optical path direction using a fixed part 9 as shown in FIG. 4, the return light B reaching the laser light source is reduced.

[0023]

[Effect of device]

 As described above in detail, in the fixing part of the present invention, the rectangular optical element is fitted in the concave portion and the corner of the optical element and the corner of the concave portion are adhered to each other. It is possible to obtain a strong bonding strength even if the total bonding area is small, and it is easy to set the aim of the bonding agent injection position. Even if the amount of the bonding agent is slightly excessive with respect to the narrow bonding margin, the risk of the bonding agent protruding to the optical path side is small. Therefore, the assembly work combined with the optical element is easy and the production can be performed with high yield.

The optical isolator of the present invention can reduce the bonding margin of the optical element, which is economical and easy to manufacture.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a fixing part to which the present invention is applied.

FIG. 2 is a perspective view showing another embodiment of a fixing component to which the present invention is applied.

FIG. 3 is a perspective view showing another embodiment of a fixing component to which the present invention is applied.

FIG. 4 is a perspective view showing another embodiment of a fixing component to which the present invention is applied.

FIG. 5 is a sectional view showing an embodiment of an optical isolator to which the present invention is applied.

FIG. 6 is a perspective view showing a conventional fixing component.

[Explanation of symbols]

1 is a cylindrical magnet, 2 is a Faraday rotator, 3 is a polarizer, 4
Is an analyzer, 5 is an optical path, 6 is a joining margin, 7 is a concave portion, 8 is an escape portion, 9 is a fixed part, 10 is a corner of a polarizer, 11 is a bonding agent, and 12 is a case body.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toshihiko Nagao 2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd. Precision Materials Research Laboratory

Claims (3)

[Scope of utility model registration request] 1. A fixed component having a recess into which a rectangular optical element is fitted, and an optical path being open to the recess,
The fixed part of the optical element, wherein the recess has a relief portion at a corner. 2. An optical isolator for arranging a plurality of optical elements to select transmitted light and transmitted return light and selectively block the progress of the returned light, wherein the optical element is rectangular and the optical element is fixed. The component has a concave portion into which the optical element is fitted, the optical path is opened in the concave portion, and the concave portion is provided with a relief portion at a corner, and the corners of the optical element and the fixed component are bonded with a bonding agent. Optical isolator characterized by being used. 3. The optical isolator according to claim 2, wherein the recess has a bottom surface inclined with respect to the optical path direction, the optical element is in close contact with the bottom surface, and the incident surface is inclined with respect to the optical path direction.