JPH0980257A - Method for coupling waveguide and optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the coupling method for the waveguide and optical fiber which is short in manufacture time, high in reliability, and low in connection loss. SOLUTION: As for the coupling method for the optical waveguide and optical fiber of an optical waveguide module which has a waveguide block and optical fiber arrays provided at the incidence-side end part and projection-side end part of the waveguide block, the coupled end surfaces of the waveguide block 22aa and optical fiber arrays 26aa and 30aa are ground slantingly by using a disk type grinding wheel 31 whose outer peripheral part is sectioned in a V shape and made to abut against each other, and after the optical axes are adjusted, they are coupled by using adhesives 35 and 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide and an optical fiber of an optical waveguide module having a waveguide block and an optical fiber array provided at the incident side end and the emitting side end of the waveguide block. Regarding the combination method.

[0002]

2. Description of the Related Art With the development of optical communication technology, conventional light sources,
In addition to optical fibers and receivers, optical splitters
Optical components such as optical switches, optical switches, and optical multiplexers / demultiplexers are required. Small size, mass productivity, and high reliability were essential for these optical components. Since it is very difficult for the conventional fiber type and bulk type to meet the above-mentioned requirements, practical application of a waveguide type optical component has been desired.

At the present time, the biggest problem in putting the waveguide type optical component to practical use is how efficiently and stably the connection between the optical waveguide constituting the waveguide type optical component and the input / output optical fiber is made. There is a point. As a method for connecting the optical waveguide and the input / output optical fiber, a method using an ultraviolet curable adhesive (so-called UV adhesive), which is expected to reduce costs, is generally used.

Here, the structure of the optical waveguide module will be described by taking a 1 × 4 splitter module as an example.

As shown in FIG. 3, the 1 × 4 splitter module 1 includes a waveguide block 2, an incident side optical fiber array 3 connected to an input side (left side in the figure) of the waveguide block 2, and a waveguide. The output side optical fiber array 4 is connected to the output side (right side in the figure) of the block 2.
The waveguide block 2 is constructed by covering the upper surface of a waveguide element 5 in which an optical waveguide is formed on a quartz substrate with a quartz dummy plate 6 of the same size as that of the waveguide element 5 and bonding and fixing both with a UV adhesive. . This is because the quartz dummy plate 6 prevents the optical waveguide (core) from chipping or sagging (curved surface) when polishing both end surfaces of the optical waveguide.

The incident-side optical fiber array 3 has a single-core type V-groove block 7 made of quartz in which V-grooves are formed and a holding plate 9. A core optical fiber 8 is arranged, a pressing plate 9 is covered on the optical fiber 8, and the optical fiber 8 is bonded and fixed with a UV adhesive.

The output side optical fiber array 4 is a quartz four-core V-groove block 10 having four V-grooves and a holding plate 11.
Having four cores and four cores of the tape fiber 12 on the output side are arranged in the four V-groove blocks of the four-core V-groove block 10, the pressing plate 11 is covered over the cores, and they are bonded and fixed with a UV adhesive. Is.

In this way, both end faces of the waveguide block 2 and the end faces of the optical fiber arrays 3 and 4 are mirror-polished, and the end face of the optical fiber and the optical waveguide (core) portion that cause connection loss are damaged. It is finished until it disappears. The waveguide block 2 and the optical fiber arrays 3 and 4 which have been polished are arranged on a precision fine movement table, and the power of light emitted from the incident side single-core optical fiber 8 and emitted from the 4-core tape fiber 12 is adjusted. Adjust the optical axis while monitoring. After adjusting the optical axis, the modularization is completed by adhering and fixing the end faces (mirror faces) of the waveguide block 2 and the optical fiber arrays 3 and 4 with a UV adhesive (Japanese Patent Application No. 6-221987).
issue).

[0009]

By the way, generally, both end faces of the waveguide block and the end face of the optical fiber array are mirror-polished, so that the end face of the optical fiber and the optical waveguide (core) portion which cause a connection loss are eliminated. Finished while observing the end face. Therefore, the following problems occur.

(1) The polishing process takes a long time (about 30 minutes per end face), and workability is poor.

(2) Surface sagging occurs, which is a cause of an increase in connection loss.

(3) An angle deviation occurs between the coupling end faces, which is a cause of an increase in connection loss.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above problems and provide a method of coupling a waveguide and an optical fiber that has a short manufacturing time, high reliability, and low connection loss.

[0014]

In order to achieve the above object, the present invention provides an optical waveguide having a waveguide block and optical fiber arrays provided at the incident side end and the emitting side end of the waveguide block. In the method of coupling a waveguide of a module and an optical fiber, the coupling end faces of the waveguide block and the optical fiber array are diagonally ground using a disk-shaped grindstone having a V-shaped cross-section at the outer peripheral portion, and the optical components are butted together. After the axis is adjusted, it is bonded with an adhesive.

In addition to the above structure, the present invention has a grindstone with a roughness of 3
It is preferably number 000.

According to the above construction, when the coupling end faces of the waveguide block and the optical fiber array are cut using a disc-shaped grindstone, the processed end faces are in a good condition not inferior to the mirror-polished surface. Therefore, the polishing time is shortened. Further, since there is no slight angle deviation during polishing and the reproducibility is good, connection loss is reduced and reliability is improved.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

2 (a) to 2 (g) are process diagrams showing an embodiment when the method of coupling a waveguide and an optical fiber of the present invention is applied to a 1 × 4 splitter module.

First, the dummy plate 2 is placed on the optical waveguide device 20.
1 is covered, and both are bonded and fixed with a highly elastic, heat-resistant and transparent UV adhesive to form the waveguide block 22. The incident-side single-core optical fiber 23 is arranged in the V-groove of the quartz V-groove block 24, covered with a retainer 25, and fixed with a highly elastic, heat-resistant and transparent UV adhesive. A core type optical fiber array (incident side optical fiber array) 26 is formed. Output side 4-core tape fiber 2
7 is placed in the V-groove of the V-groove block 28 made of quartz (four-core fiber pair four V-grooves), and the pressing plate 29 is covered from above, and both are highly elastic, heat-resistant, and transparent UV bonding. Adhesion and fixation with an agent to form an emission side four-core type optical fiber array (emission side optical fiber array) 30 (Fig. 2 (a),
(B)).

The vicinity of both the entrance and exit side end surfaces of the waveguide block 22 assembled as described above, the entrance side optical fiber array 26 and the exit side optical fiber array 3
The vicinity of the end surface of 0 is ground and finished by a dicing machine mainly used for grinding electronic parts, semiconductors and the like. In this dicing machine, a disk-shaped grindstone (V-shaped grindstone) 31 having a V-shaped cross section is used, and the waveguide block 22 and the incident side optical fiber array 2 are used.
6. The output side optical fiber array 30 is ground in the vertical direction. For this reason, the cut end faces 22a, 26a, 26
b and 30a are processed obliquely (Fig. 2 (c),
(D)).

Incident-side optical fiber array 26 after grinding
The aa, the waveguide block 22aa, and the output-side optical fiber array 30aa are arranged in this order on the precision micro-moving table (not shown), and the end faces (26a and 22a, 22b and 30a) that have been machined together are abutted to each other, and Single-core optical fiber 23
Light is incident in the direction of the arrow 32, and the optical axis is adjusted while monitoring the power of the emitted light emitted from the emission side four-core tape fiber in the direction of the arrow 33 (FIG. 2 (e)).

After the optical axis adjustment, the optical fiber array 26aa
Epoxy UV adhesive 3 with η _D = 1.45 to 1.46, which is approximately equal to the refractive index of the core of the optical fiber 23, is provided in the gap 34 between the end face 26a of the optical fiber 23 and the end face 22a of the waveguide block 22aa.
5 is applied to the gap 36 between the end face 22b of the waveguide block 22aa and the end face 30a of the optical fiber array 30aa,
Η _D = almost equal to the refractive index of the core of the tape fiber 27
By applying an epoxy UV adhesive 37 of 1.45 to 1.46 (FIG. 2 (f)) and irradiating and fixing the UV UV (FIG. 2 (g)), a 1 × 4 splitter module is obtained. It is formed.

FIG. 1 is an external perspective view of a 1 × 4 splitter module to which the waveguide and optical fiber coupling method of the present invention is applied.

As shown in the figure, the 1 × 4 splitter module 38 includes a waveguide block 22aa formed in a parallelogram shape and light provided at the incident side end and the output side end of the waveguide block 22aa. Fiber array 26aa,
30 aa and the gaps 34, 3 of the end faces abutting each other
It can be seen that 6 is filled with adhesives 35 and 37 and bonded.

With this configuration, when the coupling end faces of the waveguide block 22aa and the optical fiber arrays 16 and 30 are cut using the V-shaped grindstone 31, each of the processed end faces 26a, 22a, 22b, The polishing time is shortened because 30a is in a good state as good as a mirror-polished surface. Further, there is no slight angle deviation during polishing, and reproducibility is good. Furthermore, a high degree of reflection attenuation can be obtained by oblique grinding, and it is less susceptible to environmental temperature. Therefore, connection loss is reduced and reliability is improved.

Next, the optimum conditions will be described.

As a V-shaped grindstone for grinding, a roughness of No. 3000 is optimum.

The No. 1000 and No. 2000 V-shaped grindstones are too coarse-grained so that the coupling end face is far from the mirror state, the loss is large (0.2 dB), and the return loss is inferior by about 10 dB. Further, the life of the whetstone (the number of grindable works) of the # 4000 V-shaped whetstone is about half.

On the other hand, the # 3000 V-type grindstone was not inferior to the mirror polishing in terms of loss and return loss, and the life of the grindstone was equivalent to that of the # 2000 V-type grindstone. Therefore, 300
No. 0 V-shaped grindstone was adopted.

As described above, according to this embodiment, the following effects are obtained.

(1) Since the mirror-polishing step is omitted, the manufacturing time is greatly shortened (30 minutes in the conventional case, 1 minute in the present embodiment).

(2) The surface sagging that occurs during buffing is eliminated, and the cause of deterioration of connection loss is eliminated.

(3) Since there is no slight angle deviation during polishing and the reproducibility is good, the connection loss can be reduced.

(4) The adoption of the V-shaped grindstone facilitates oblique grinding.

In this embodiment, the case of the 1 × 4 splitter module has been described, but the present invention is not limited to this, and any other type of optical waveguide module including a waveguide block and an optical fiber array can be used. (1 × 8 splitter module, 1 × 16 splitter module, optical multiplexer / demultiplexer, etc.) may be applied.

[0036]

In summary, according to the present invention, the following excellent effects are exhibited.

The coupling end faces of the waveguide block and the optical fiber array are obliquely ground using a disc-shaped grindstone having a V-shaped cross section at the outer peripheral portion, and the optical axes are adjusted by butting.
Since the bonding is performed with an adhesive, it is possible to realize a method of connecting a waveguide and an optical fiber that has a short manufacturing time, high reliability, and low connection loss.

[Brief description of drawings]

FIG. 1 is an external perspective view of a 1 × 4 splitter module to which a method of coupling a waveguide and an optical fiber according to the present invention is applied.

FIG. 2 illustrates a method of coupling a waveguide and an optical fiber according to the present invention.
It is a process drawing which shows one embodiment when applied to a x4 splitter module.

FIG. 3 is an external perspective view of a 1 × 4 splitter module to which a conventional method of coupling a waveguide and an optical fiber is applied.

[Explanation of symbols]

 22aa Waveguide block 23 Optical fiber (incident side single-core optical fiber) 26aa, 30aa Optical fiber array 27 Tape fiber (emission side 4-core tape fiber) 35,37 Adhesive (epoxy UV adhesive) 38 1 × 4 splitter module

Claims (2)

[Claims] 1. A method for coupling a waveguide and an optical fiber of an optical waveguide module having a waveguide block and an optical fiber array provided at an incident side end and an output side end of the waveguide block, wherein The coupling end surfaces of the waveguide block and the optical fiber array are obliquely ground using a disk-shaped grindstone having a V-shaped cross section at the outer peripheral portion, and the optical axes are adjusted by butting and then bonded with an adhesive. A method of coupling a waveguide and an optical fiber. 2. The method of coupling a waveguide and an optical fiber according to claim 1, wherein the grindstone has a roughness of No. 3000.