JPH0868912A - End face treatment of optical fiber - Google Patents

Abstract

PURPOSE: To form lenses having a high degree of freedom in shapes with excellent productivity at the end faces of optical fibers. CONSTITUTION: A device consists of the plural optical fibers 10 arranged at prescribed intervals (pitches) and a member 2 having plural lens forming holes 21 corresponding to the pitches of the optical fibers 10. Transparent resins 31 curable by light or heat are packed into these holes 21 and thereafter, the optical fibers 10 are inserted to the prescribed extent into the holes 21 to project the resins 31 from the holes 21, by which projecting parts 32 are formed at the ends of the holes. Light or heat is applied on these projecting parts 32 to cure the resins, by which the lenses 30 are formed at the end faces of the fibers 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing an end face of an optical fiber, and more particularly to a method for manufacturing an optical module suitable for optical communication, optical information processing, optical interconnection and the like.

[0002]

2. Description of the Related Art In optical communication, optical information processing, etc., an optical module in which an optical fiber array and a lens array are combined is used. As an example of a method of manufacturing the optical module, for example, electronic information communication in 1991. In the autumn meeting C-251 of the society, a method is proposed in which the end portion of the optical fiber array is melted by direct electric discharge machining to integrally form a lens. In this method, a predetermined amount of an optical fiber is placed in a V groove formed on a Si substrate with high precision, the diameter of this portion is reduced by etching, and then the tip portion is melted by discharge heating and the surface tension is changed by the surface tension. It is a lens that is made into a spherical shape. In addition, JP-A-5-107427
In the publication, the end face of the optical fiber is brought into contact with the photosensitive resin,
A method has been proposed in which the end face of the optical fiber is processed into a spherical surface by irradiating it with light and then curing the photosensitive resin.

[0003]

However, in forming a lens by spheroidizing, the tip of the fiber is melted and spheroidized by its surface tension. Therefore, the minute volume of the tip is controlled only by the amount of heat from a flame or discharge. Since the spherical surface is processed with a spherical surface, the radius of curvature of the front spherical portion is likely to vary, the precision of the front spherical portion cannot be sufficiently obtained, and a problem remains in productivity in the case of mass production. In addition, in the method of attaching the photosensitive resin to the end face of the optical fiber, there is a limit to the amount of resin to be attached to the fiber tip, and the radius of curvature of the lens that can be manufactured is limited, and a lens having a small radius of curvature is manufactured. There are problems such as not being able to.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for treating an end face of an optical fiber which is excellent in productivity and has a large degree of freedom in shape.

[0005]

In order to solve the above problems, the present invention provides (1) a plurality of optical fibers arranged at a predetermined interval (pitch) and a plurality of optical fibers corresponding to the pitch of the optical fibers. A member having a hole for forming a lens, the hole is filled with a transparent resin that is cured by light or heat, and then a predetermined amount of the optical fiber is inserted into the hole to project the resin from the hole. Form a convex part at the end of the hole,
The convex portion is cured by applying light or heat to form a lens on the end face of the fiber, or (2) a substrate having optical fiber holding grooves at predetermined intervals (pitch) is provided on the substrate. An optical fiber holding member formed by arranging the end portion of the optical fiber so as to protrude by a predetermined amount, and a lens array member having a plurality of lens forming holes corresponding to the pitch of the optical fibers are used, and resin is provided in the holes. After filling, the end face of the lens array member is arranged so as to contact the end face of the optical fiber holding member or face each other via a spacer having a predetermined thickness, and the predetermined amount of the optical fiber is inserted into the hole. Then, the resin is projected from the hole to form a convex portion at the end of the hole, and the shape of the convex portion is controlled to form a lens on the end face of the fiber. ,
(3) The inside of the hole is processed at a predetermined position so as to be smaller than the outer diameter of the optical fiber to be inserted,
When inserting the optical fiber, to limit the insertion amount of the optical fiber at the position to control the shape of the convex portion of the resin at the hole end to form a lens on the end face of the optical fiber, (4) As a lens array member forming the holes,
A member is used which is opaque to the wavelength of the light transmitted through the optical fiber or has a film opaque to the wavelength of the light transmitted through the optical fiber in a part or all of the region other than the hole. It was done.

[0006]

A transparent resin which is composed of a plurality of optical fibers arranged in a pitch at a predetermined interval and a member having a plurality of lens forming holes corresponding to the pitch of the optical fibers, and which is hardened by light or heat in the holes. After filling with a predetermined amount of the optical fiber into the hole, the resin is projected from the hole to form a convex portion at the end of the hole, and light or heat is applied to the convex portion to cure the resin. Thus, a lens is formed on the end face of the fiber, and thus, the end face treatment of an optical fiber having excellent productivity and a large degree of freedom in shape can be performed.

Alternatively, there is provided an optical fiber holding member having a substrate having optical fiber holding grooves provided at a predetermined interval (pitch), and an end portion of the optical fiber protruding from the substrate by a predetermined amount, and the optical fiber holding member, A lens array member having a plurality of lens forming holes corresponding to the pitch of the optical fiber is used, and after filling the holes with resin, the end face of the optical fiber holding member is brought into contact with or predetermined to the end portion of the lens array member. Are arranged so as to face each other via a spacer having a thickness of, and a predetermined amount of the optical fiber is inserted into the hole, and the resin is projected from the hole to form a convex portion at the end of the hole. By controlling the shape of the convex portion to form a lens on the end face of the fiber, it is possible to manufacture a lens having excellent productivity and good uniformity.

Alternatively, the inside of the hole is processed at a predetermined position so as to be smaller according to the outer diameter of the optical fiber to be inserted, and when the optical fiber is inserted, the optical fiber is inserted at the position. By limiting the insertion amount and controlling the shape of the resin convex part at the hole end to form a lens on the end face of the optical fiber, it is possible to manufacture a lens with excellent productivity and good uniformity. And

The lens array member forming the holes is opaque to the wavelength of light transmitted in the optical fiber, or has a wavelength of light transmitted in the optical fiber in a part or all of the region other than the hole. By using a member having an opaque film formed thereon, it is possible to provide a high-performance optical fiber array with less optical crosstalk.

[0010]

FIG. 1 is a diagram for explaining one embodiment of the present invention. FIG. 1 (a) is a perspective view and FIG. 1 (b) is a sectional view taken along line BB of FIG. 1 (a). In the figure, 10 is an optical fiber, 20
Is a member having a hole 21 through which the optical fiber 10 is inserted,
The present invention, as shown in the figure, includes a plurality of optical fibers 10 arranged at predetermined intervals (pitch), and these optical fibers 1.
A member 20 having a through hole 21 corresponding to a pitch of 0 and having an inner diameter slightly larger than the outer diameter of the optical fiber 10 is used, and the hole 21 of the member 20 is filled with a transparent resin 31 which is cured by light or heat. Then, the optical fiber 10 is inserted into the hole 21 by a predetermined length, and the resin 31 is partially extruded,
The extruded resin 31 is formed into a spherical surface 32 by its surface tension, and thereafter, the resin 31 is cured by applying light or heat to form a convex portion 30 forming a lens on the tip surface of each optical fiber 10. It was done.

FIG. 2 is a diagram for explaining a specific example of the optical fiber end face processing method according to the present invention.
As shown in (a), for example, a transparent flat glass substrate 2
The holes 21 slightly larger than the diameter of the fiber to be inserted into the 0 are inserted at a predetermined pitch,
As shown in FIG. 2B, an epoxy-based photo-curable resin 31 that is cured by ultraviolet rays is filled in the hole 21 (as a filling method, direct injection or dipping the glass substrate in the resin, It is possible to remove the excess resin).

On the other hand, as shown in FIG. 2 (c), the optical fiber is patterned by photolithography on the members 41a and 41b such as a silicon substrate and anisotropic etching by using KOH aqueous solution as an etching solution. By using the optical fiber holding member 40 in which the members 41a and 41b are sandwiched by the V grooves 42a and 42b so as to hold the optical fiber, a predetermined space (in this case, the substrate 20
Pitch and pitch) of the V groove 42a, 4 for holding the fiber
2b is manufactured, and the V groove 42 of these members 41a and 41b is formed.
An optical fiber array is formed by sandwiching the optical fiber 10 between a and 42b and fixing the tip end portion by protruding a predetermined amount.

As described above, the member 20 in which the hole 21 is filled with the resin 31 and the optical fiber array in which the plurality of optical fibers 10 are integrally formed are formed into the hole portion 21 as shown in FIG. When the optical fiber 10 is aligned with the optical fiber 10 and the optical fiber 10 is inserted into the hole 21 by a predetermined amount, the resin 31 is extruded from the hole 21 by the surface tension as shown in FIG. The curved portion 30 makes the surface spherical or aspheric. After that, the resin 31 is cured by irradiating the ultraviolet ray 60 to fix the tip of the fiber and form a lens on the end face of the fiber. At this time, the end face of the fiber holding member 40 is brought into contact with the end face of the member 20 having the hole 21, or a flat plate (spacer) having a predetermined thickness.
The shape of the lens (the shape of the extruded portion 30) is controlled by controlling the insertion amount of the optical fiber depending on whether they are opposed to each other via 60.
Control. Further, it is possible to reduce the optical crosstalk between the optical fibers by using the glass substrate 20 on which the light shielding film is formed on the lens formation side surface.

Furthermore, the lens forming portion 30 can be manufactured by various methods other than the above-mentioned method. For example, as shown in FIG. A silicon substrate having 100 faces),
By using the oxide film having a square opening as a mask and performing etching for a predetermined time by the above-described anisotropic etching method, it is possible to form a square pillar hole 26 having a slope inclined by about 55 degrees with respect to the opening. At this time, by appropriately determining the size of the mask opening, the hole size can be made smaller than the outer diameter of the optical fiber 10 at an appropriate position on the way,
It is possible to limit the insertion amount of the fiber 10. Further, it is possible to manufacture it by using a photosensitive glass. This is because, for example, an ultraviolet-sensitive glass is used for the substrate 20 and ultraviolet rays having a high degree of parallelism are irradiated through a mask in which circular openings for transmitting ultraviolet rays are arranged in an array, and then this portion is crystallized by heat treatment and etched. By removing this crystallized portion, a hole is formed and the lens forming member 20 is manufactured. Alternatively, the substrate may be exposed to ultraviolet rays and heat-treated again to crystallize the entire substrate. In the above manufacturing method, the etching conditions are controlled so that FIG.
As shown in (b), by changing the inclination angle of the wall surface in the hole 26, it is possible to form a portion 27 smaller than the outer diameter of the fiber and limit the insertion amount of the optical fiber. .

It is also possible to use a resin member for the lens forming member 20. 4A and 4B are views showing an example of a method of manufacturing the lens forming member using a resin member, FIG. 4A is a perspective view, and FIG. 4B is a sectional view taken along line BB of FIG. 4A. In the figure, 70 is a metal rod having a diameter slightly larger than the diameter of the optical fiber to be used, 71 and 72 are members constituting a mold, and these molds 71 and 72 have a cavity 73 formed therein. Are used in combination. In addition, these molds 71 and 72 have holes 71a and 7 into which a metal rod 70 having a diameter slightly larger than the diameter of the optical fiber used is inserted.
2a. In this embodiment, a box-shaped hollow portion 7 is provided inside.
In the molds 71 and 72 forming the 3
After a metal rod 70 having an outer diameter slightly larger than the outer diameter of the optical fiber used at a predetermined pitch is inserted through a pair of opposite sides of the resin, resin 75 is filled and cured by heat, and then the metal rod 70 is inserted. And the molds 71 and 72 are removed, and the resin 75
First, a lens forming member (corresponding to 20 in FIG. 1) having a hole having a diameter corresponding to the outer diameter of the metal rod 70 is manufactured (the end face may be polished if necessary). At this time, it is possible to reduce the optical crosstalk between the fibers by using a resin that is opaque to the wavelength of the light transmitted through the optical fibers. The present invention is not limited to the above method, and various modifications can be made without departing from this spirit.

[0016]

【The invention's effect】

Effect on Claim 1: It is possible to provide an end face processing method for an optical fiber which is excellent in productivity and has a large degree of freedom in shape. Effects on Claims 2 and 3: It is possible to manufacture a lens having excellent productivity and good uniformity. Effect on Claim 4: It is possible to provide a high-performance optical fiber array with less optical crosstalk.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an optical fiber end face processing method according to the present invention.

FIG. 2 is a diagram showing a processing procedure of an end face of an optical fiber.

FIG. 3 is a diagram showing another method of treating the end face of the optical fiber.

FIG. 4 is a diagram illustrating a method for manufacturing a lens forming member.

[Explanation of symbols]

10 ... Optical fiber, 20 ... Lens forming member, 21 ... Hole,
30 ... Convex part (lens part), 31 ... Resin, 40, 41a,
41b ... Fiber holding member, 42a, 42b ... Fiber holding V groove, 50 ... Ultraviolet source line, 60 ... Spacer, 70 ...
Hole forming metal rods, 71, 72 ... Mold, 75 ... Resin forming lens forming member.

Claims (4)

[Claims] 1. A plurality of optical fibers arranged at a predetermined interval (pitch) and a member having a plurality of lens-forming holes corresponding to the pitch of the optical fibers, the holes being cured by light or heat. After filling the transparent resin,
A predetermined amount of the optical fiber is inserted into the hole, the resin is projected from the hole to form a convex portion at the end portion of the hole, and the convex portion is cured by applying light or heat to the end surface of the fiber. A method for treating an end face of an optical fiber, which comprises forming a lens. 2. An optical fiber holding member comprising a substrate having optical fiber holding grooves provided at a predetermined interval (pitch), and an end portion of the optical fiber protruding from the substrate by a predetermined amount.
Using a lens array member having a plurality of lens forming holes corresponding to the pitch of the optical fiber, after filling the holes with resin, contact the end face of the optical fiber holding member to the end of the lens array member or Arranged so as to face each other through a spacer having a predetermined thickness, a predetermined amount of the optical fiber is inserted into the hole, the resin is projected from the hole, and a convex portion is formed at the end of the hole. A method for processing an end face of an optical fiber, characterized in that a lens is formed on the end face of the fiber by controlling the shape of the convex portion. 3. The inside of the hole is processed at a predetermined position so as to be smaller than the outer diameter dimension of the optical fiber to be inserted, and when the optical fiber is inserted, the optical fiber of the optical fiber is inserted at the position. The method for treating an end face of an optical fiber according to claim 1 or 2, wherein the amount of insertion is limited to control the shape of the convex portion of the resin at the end of the hole to form a lens on the end face of the optical fiber. 4. The lens array member forming the hole is opaque to the wavelength of light transmitted in the optical fiber, or the wavelength of light transmitted in the optical fiber in a part or all of a region other than the hole. 3. A method for processing an end face of an optical fiber according to claim 1 or 2, wherein a member having an opaque film is used.