JPH04360107A - Aligning method for optical fiber array - Google Patents

Abstract

PURPOSE:To suppress variance in optical fiber output due to variance in radius R of curvature among optical fibers and variance of tip positioning. CONSTITUTION:Light with specific wavelength is made incident from the rear end of one optical fiber 1 by a reflection attenuation quantity measuring instrument 4 and projection light from the tip of the optical fiber 1 is reflected by a reflecting plate 3 which is installed in front of the optical fiber and at right angles to the optical fiber axis; and the reflected light is guided as return light in the optical fiber 1 again from its tip and the reflection attenuation quantity measuring instrument 4 measures the quantity of the return light. A fiber position adjustment device 5 finely vibrates the optical fiber 1 axially and positions the optical fiber where the return light becomes maximum, and the optical fiber 1 is fixed to an aligning substrate 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for aligning optical fiber arrays.

0002

2. Description of the Related Art Research is being actively conducted on increasing the speed of optical parallel transmission and multi-channel transmission for large-capacity data transmission for computers, switching equipment, etc. The optical parallel transmission module used here allows for easy coupling between optical fibers and optical elements.
A configuration with a small number of parts is required. Therefore, an optical fiber array is used in which a plurality of spherical fibers whose tips are cut or melted to have an appropriate radius of curvature R are aligned on an alignment substrate such as a V-groove substrate.

[0003] Optical fibers are aligned by making the tips of the optical fibers, which have been rounded, protrude by a certain amount from the alignment substrate. As a method of alignment, a method of aligning the wires one by one to a reference line while observing with a microscope, or a method of using an abutment plate are adopted. In the latter method using an abutment plate, if the radius of curvature R of the spherical fiber becomes small, damage may occur when the fiber is brought into contact with the abutment plate, so a method using a microscope is usually used.

0004

Problems to be Solved by the Invention As described above, processing of the tip of an optical fiber is performed by cutting or melting, but variations in the radius of curvature R are unavoidable in this method. Furthermore, in aligning optical fibers, even with a microscope, it is extremely difficult to align the tips of the optical fibers within several microns, and it becomes more difficult as the number of arrays (number of aligned fibers) increases. Therefore, even if a signal is input to the optical fiber at the same input level, the output will vary.

The present invention has been made in view of the above circumstances, and its object is to provide an optical fiber array alignment method that can suppress variations in optical fiber output due to variations in the radius of curvature of optical fibers and variations in tip alignment. Our goal is to provide the following.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an optical fiber array alignment method in which a plurality of optical fibers having hemispherical tips are aligned on an alignment substrate. The returned light from the emitted light reflected by a reflector disposed opposite the tip of the optical fiber was measured, and alignment was made at the position where the returned light was at its maximum.

[0007]

[Operation] According to the present invention, the light emitted from the tip of the optical fiber having a rounded tip is focused with a focus point corresponding to the radius of curvature R. At this time, the reflector is installed at the condensing point of the optical fiber, and most of the light emitted from the tip of the optical fiber is reflected by the reflector and guided back to the optical fiber as returned light. The amount of this returned light is measured, and the position where the amount of reflected return light is maximum becomes the focal point, so the optical fiber is aligned at the position where the amount of reflected return light is maximum.

Therefore, even if there are variations in the radius of curvature R or the protrusion length of the optical fiber tips, a constant amount of output can be obtained from the optical fiber array.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram of a method for aligning an optical fiber array according to the present invention.

In FIG. 1, reference numeral 1 denotes an optical fiber, the tip of which is machined to have a radius R=30 μm. Further, a plurality of optical fibers 1 processed in this manner are arranged in parallel, for example, five optical fibers at predetermined intervals. Note that the variation in the radius of curvature R of each optical fiber 1 at this time was 30 μm±1 μm.

Reference numeral 2 denotes an alignment substrate, which was composed of a V-groove alignment substrate prepared by photolithography on a silicon substrate, and the dimensions of the substrate were a pitch of 250±1 μm and a width of the V-groove 21 of 167±1 μm. The optical fiber 1 is placed in this V-groove 21.

3 is a reflection plate, and the reflection surface 31 is connected to the optical fiber 1.
The fiber is disposed so as to face the tip of the fiber at a predetermined distance and perpendicular to the fiber axis.

Reference numeral 4 denotes a return loss measuring device, which is connected to the rear end of the optical fiber 1 and transmits a predetermined wavelength, for example 1, to each optical fiber 1.
．． Light of 3 μm is incident, and the amount (intensity) of the reflected return light reflected by the reflection plate 3 is measured.

Reference numeral 5 denotes a fiber position adjustment device, which includes a fiber gripping mechanism 51 that grips any position in the longitudinal direction of the optical fiber 1, and which can move the fiber gripping mechanism 51 in the X and Y directions of the coordinate system set in the figure. It consists of an XY table 52. The fiber gripping mechanism 51 includes a base 511 placed on an XY table 52, a main body 512 that is pivotally supported on the base 511, and a fiber gripping mechanism 51 that penetrates through the main body 512 and has a hook-shaped tip. , the rear end is Y by the spring 514
The locking portion 513 is biased in the direction shown in FIG. When a pressing force is applied to the rear end of the locking part 513, the amount of protrusion at the tip increases, and when the pressing force is removed, the locking part 513 returns to its initial state (the amount of protrusion becomes smaller). That is, the locking portion 513
The optical fiber 1 is connected by the hooked part 513a and the tip of the main body.
It is designed to hold.

Next, the operation and alignment procedure of the above configuration will be explained.

First, a part of the first optical fiber 1 (front side in the figure) in the longitudinal direction is gripped by the fiber gripping mechanism 51 of the fiber position adjustment device 5, and the first optical fiber 1 is gripped by the return loss measuring device 4. Light with a wavelength of 1.3 μm is input from the rear end of the optical fiber 1. The light incident on the optical fiber 1 propagates through the optical fiber 1 and then exits from the tip of the optical fiber 1.

The light emitted from the optical fiber 1 reaches a reflection plate 3 installed in front of the optical fiber and perpendicular to the axis of the optical fiber, and is reflected there. The light reflected by the reflector 3 is guided back to the optical fiber 1 from its tip as return light. After propagating through the optical fiber 1, this return light returns to the return attenuation measuring device 4, and the amount of the returned light is measured by the return attenuation measuring device 4.

Since the position where the amount of reflected return light is maximum becomes the focal point, the XY table 52 of the fiber position adjustment device 5
The fiber gripping mechanism 51 is moved slightly in the X direction, that is, in the axial direction, to align the optical fiber 1 to the position where the return light is maximum, and the optical fiber 1 is temporarily fixed to the alignment substrate 2 using epoxy resin. .

Thereafter, the remaining optical fibers 1 are successively aligned in the same manner. After aligning all five optical fibers 1, they are permanently fixed with epoxy resin. The output deviation of the optical fiber array aligned in this manner was within 1%.

As explained above, according to this embodiment,
A constant amount of optical fiber array output can be obtained without being affected by variations in the radius of curvature R of the optical fibers 1 and variations in tip alignment.

[0021]

[Effects of the Invention] As explained above, according to the present invention,
Even if optical fibers with manufacturing deviations in bending radius R, etc. are used, there is an advantage that an optical fiber array with extremely small output deviations can be manufactured.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an optical fiber array alignment method according to the present invention.

[Explanation of symbols]

1...Optical fiber 2... Alignment substrate 21...V groove 3...Reflector 31...Reflective surface 4...Return loss measuring device 5...Fiber position adjustment device

Claims (1)

[Claims] Claim 1: In an optical fiber array alignment method in which a plurality of optical fibers whose tips are processed into hemispherical shapes are aligned on an alignment substrate, light emitted from the tips of the optical fibers is reflected when the light is placed opposite the tips of the optical fibers. A method for aligning an optical fiber array, which is characterized by measuring return light reflected from a plate and aligning at a position where the return light is maximum.