JP2000098177A - Optical waveguide module and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformalize transmission losses between each circuit of an optical waveguide module coupling an optical waveguide having plural ports to an optical fiber array body in which plural optical fibers are arrayed. SOLUTION: This is an optical waveguide module coupling an optical waveguide 1 having plural ports 1a to an optical fiber array body 2 in which plural optical fibers are arrayed, and regular transmission loss differences across the ports of the optical waveguide 1 are corrected by the displacements between the optical axes of the ports of the optical waveguide 1 and the optical fibers 2c at the coupling part 4 of each port to the corresponding optical fiber tip face, and difference between transmission losses of each circuit as an optical waveguide module is made smaller than that between the transmission losses across the ports of the optical waveguide 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical waveguide module in which an optical waveguide and an optical fiber array such as a multi-core optical connector are connected, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As an example of an optical waveguide, there is an optical waveguide having a plurality of input ports and a single output port called a mode combiner as shown in FIG. FIG. 4 (A)
FIG. 4B is a plan view, FIG. 4C is an enlarged view of a main part of the mode combiner, 11 is a mode combiner, and 11a is a single view. A mode circuit portion, 11b is a slab circuit portion, 12 is a multi-core optical connector, 13 is a tape-shaped optical fiber core, 14 is a single-core optical connector, 15 is a single-core optical fiber, and 16 and 17 are coupling portions. .

The mode combiner 11 has a plurality of single mode circuit sections 11a and one slab circuit section 11b.
And a plurality of single-mode optical fibers of the left-side tape-shaped optical fiber core 13 and the multi-core optical connector 12 through the coupling portion 16 to a plurality of input ports of the mode combiner 11. The entered light travels through the single mode circuit section 11a, respectively, and
1b, the mixture is output from one output port on the right side to the multi-mode single-core optical fiber core 15 of the single-core optical connector 14 via the coupling portion 17.

[0004]

In the above-mentioned mode combiner, it is expected that the transmission loss of each of the plurality of input ports is exactly the same. However, when the angle at the time of entering the slab circuit section 11b from the single mode circuit section 11a of each port is large, some light is emitted and transmission loss increases. Therefore, the transmission loss is reduced by optimizing the parameters such as the shape and dimensions of the slab circuit section to make the transmission loss uniform, but it is necessary to completely eliminate the transmission loss difference due to the circuit shape and the like. Can not.

In addition, this mode combiner processes a core member laminated on a substrate by photolithography technology or the like, like a general optical waveguide, so that the difference in transmission loss due to the circuit shape between the above ports is small. , Will occur regularly in all mode combiners that are manufactured. When assembling a system using an optical waveguide such as a mode combiner having a regularity in the transmission loss difference between a plurality of ports, it is necessary to electrically correct the transmission loss difference. However, this electrical correction is not preferable because it causes a speed limitation when performing high-speed switching or the like.

An object of the present invention is to provide an optical waveguide module and a method for manufacturing an optical waveguide module in which, when an optical waveguide having a plurality of ports has a regular transmission loss difference between ports, the difference in transmission loss is compensated for as small as possible. It provides a method.

[0007]

An optical waveguide module according to the present invention is an optical waveguide module in which an optical waveguide having a plurality of ports and an optical fiber array in which a plurality of optical fibers are arrayed are connected. The difference in the regular transmission loss between the ports is compensated for by the displacement of the optical axis between the port of the optical waveguide and the optical fiber at the joint between each port and the corresponding end face of the optical fiber. The difference in transmission loss of the circuit is smaller than the difference in transmission loss between the ports of the optical waveguide.

In manufacturing this optical waveguide module, the transmission loss of each port of the optical waveguide is measured in advance. Then, a loss difference obtained by subtracting the transmission loss of each port from the maximum value of the transmission loss is obtained for each port. Then, based on data indicating the relationship between the predetermined coupling loss and the optical axis shift amount, the optical axis shift amount that provides the coupling loss corresponding to the loss difference is obtained for each port. Next, an optical fiber array is manufactured by displacing the position of each optical fiber of the optical fiber array according to the optical axis shift amount, and the optical waveguide and the optical fiber array are coupled.

[0009]

FIG. 1 is a view for explaining an embodiment of an optical waveguide module according to the present invention. FIG. 1 (A) is a plan view of the optical waveguide, and FIG. 1 (B) is a front view of the optical waveguide. , FIG.
1C is a front view of the optical fiber array, FIG. 1D is a plan view of the optical fiber array, FIG. 1E is a partially enlarged front view of the optical fiber array, and FIG. It is a top view of a waveguide module. In FIG. 1, 1 is an optical waveguide, 1a is a port, 2 is an optical fiber array, 2a is a base, 2b is a groove,
2c is an optical fiber, 2d is a holding plate, 3 is a tape-shaped optical fiber core, and 4 is a coupling portion.

The optical waveguide 1 has a plurality of ports 1a on the tip end surface. Generally, each port is arranged in a line at a constant interval L. The shape of the internal circuit of the optical waveguide 1 is not particularly limited. It may have a circuit such as the mode combiner described above, may include a simple branch circuit, or may be a simple straight circuit.

In the case of a mode combiner, a plurality of input ports and one output port are provided. However, depending on the optical waveguide, there may be a plurality of input ports and output ports. . However, in any case, the transmission loss of each port must have a regular difference. The regular transmission loss difference is mainly based on the circuit shape, and appears regularly when a plurality of optical waveguides are manufactured. Therefore, the regular transmission loss difference does not include a measurement error and a manufacturing error between a plurality of optical waveguides.

The optical fiber array 2 coupled to the optical waveguide 1 has an optical fiber 2c inserted into a plurality of grooves 2b provided in parallel with the surface of a substrate 2a made of silicon, glass, resin molded body or the like. Then, it is pressed and fixed by the holding plate 2d, and the front end surface is polished as necessary. At the rear end of the optical fiber array 2, a tape-shaped optical fiber core 3 in which a plurality of optical fibers 2c are appropriately coated extends. The cross-sectional shape of the groove 2b can be various shapes such as a V-shape, a U-shape, a trapezoid, and a rectangle, but a V-shape that can be precisely positioned by contacting the optical fiber at three points is preferable.

In the case of providing a groove in the optical fiber array, in the prior art, the interval of the groove is adjusted to the port interval of the optical waveguide so that each port of the optical waveguide and the optical axis of the optical fiber of the optical fiber array do not shift. Although the grooves are arranged to reduce the coupling loss as much as possible, the optical waveguide module according to the present invention employs a completely different idea. That is, in the optical fiber array 2 used in the optical waveguide module of the present invention, the groove 2 of the optical fiber array is set in accordance with the regular transmission loss difference for each port 1a of the optical waveguide 1.
The position of the groove 2b is displaced so that the optical axis of the optical fiber 2c inserted into the optical fiber 2b is shifted from the optical axis of each port of the optical waveguide.

More specifically, the transmission loss of each port of the optical waveguide 1 is determined in advance, and the difference between the maximum value and the transmission loss of each port is determined for each port. Then, based on the data indicating the relationship between the predetermined coupling loss and the optical axis shift amount, the optical axis shift amount that gives the coupling loss corresponding to the transmission loss difference is obtained. FIG. 2 is a graph showing an example of data indicating a relationship between a predetermined coupling loss and an optical axis shift amount, and showing a relationship between the coupling loss and the optical axis shift amount. The relationship between the coupling loss and the optical axis shift amount can be calculated by a relational formula, instead of the graph of FIG.

Next, a groove is formed by displacing the position of the groove 2b of the optical fiber array 2 by a dimension corresponding to the optical axis shift amount for each port. Accordingly, the positions of the optical fibers arranged in the grooves are shifted by a dimension corresponding to the optical axis shift amount. If there is no difference in the transmission loss of each port of the optical waveguide, FIG.
As shown by a dotted line in FIG.
In the case where there is a regular transmission loss difference between the ports of the optical waveguide, as shown by a solid line in the example of P2 and P3 in FIG. It is arranged at the position shifted only by.

The displacement of the groove position corresponding to the optical axis shift amount can be displaced in either the depth direction of the groove or the arrangement direction of the groove, but the optical fiber is inserted into the groove. When a method of fixing by pressing with a presser plate is adopted, it is desirable to displace the grooves in the arrangement direction so that the depth of the grooves is constant. The sectional shape of the groove may be a U-shape, but a V-shape is desirable in order to accurately determine the position of the optical fiber according to the groove position.

As described above, each groove 2b is formed by displacing the position of the groove in accordance with the amount of optical axis shift as described above, and the light is removed by exposing the coating at the end of the tape-shaped optical fiber core 3. The fibers 2c are inserted into the respective grooves 2b with their leading end surfaces aligned, pressed by the holding plate 2d, and fixed with an adhesive or the like to obtain the optical fiber array 2. Thereafter, the tip surface is polished if necessary. Then, each port of the optical waveguide 1 and each optical fiber of the optical fiber array 2 are opposed to each other and fixed with an adhesive or the like to form a coupling portion 4. FIG. 1F shows an optical waveguide module formed in this manner.

As described above, the amount of optical axis shift is given to the coupling portion so as to generate a coupling loss according to the difference between the maximum value of the transmission loss of each port of the optical waveguide and the loss of the transmission loss of each port. The transmission loss of each circuit of the completed optical waveguide module is equalized to a value equal to or slightly higher than the maximum value of the transmission loss of each port of the optical waveguide module. You.

In the embodiment of the optical waveguide module shown in FIG. 1, an example is shown in which the optical waveguide and the optical fiber array are formed separately, and they are opposed to each other and coupled. It is also possible to manufacture the array body integrally. FIG. 5 is a perspective view showing such a case, in which 5 is a main body, 5a is an optical waveguide, 5b is an optical fiber array, 5c is a single-core optical fiber mounting portion, 5d and 5e are grooves, 6 Is an optical fiber ribbon, 6a is an optical fiber,
Reference numeral 7 denotes a single-core optical fiber, 7a denotes an optical fiber, 8 and 9 denote holding plates, and 10 denotes a coupling portion.

The optical waveguide section 5a includes an optical fiber array section 5
A circuit having a plurality of ports arranged at a constant interval on the b side and one port on the single-core optical fiber mounting section 5c side is formed. Each port of the optical waveguide has a regular difference in transmission loss. The grooves 5d of the optical fiber array section 5b are arranged with their optical axes shifted so as to generate a coupling loss corresponding to the difference between the maximum transmission loss of each port of the optical waveguide section and the transmission loss of each port.

Therefore, each groove 5d is formed at a position slightly deviated from the port position of the optical waveguide section 5a. The groove 5e of the single-core optical fiber mounting portion 5c is formed in accordance with the port position of the optical waveguide. The grooves can be formed by wet etching in addition to the dicer.

The tape-shaped optical fiber core wire 6 is removed by removing the coating of the terminal portion to expose the optical fiber 6a.
a is inserted into the groove 5d, pressed with the holding plate 8, and fixed with an adhesive or the like. At this time, the coupling portion 10 is formed between the distal end face of the optical fiber 6a and the port of the optical waveguide 5a. The end of the single-core optical fiber 7 is also removed to expose the optical fiber 7a, the optical fiber 7a is inserted into the groove 5e, held down by the holding plate 9, and fixed with an adhesive or the like.

In this example, the optical fiber array according to the present invention is a portion composed of an optical fiber array portion 5b, an optical fiber 6a and a holding plate 8, and the optical fiber 6a has a predetermined optical axis shift amount. In a state where the optical waveguide is provided, it is coupled to each port of the optical waveguide of the optical waveguide section 5a by the coupling section 10. In the example shown in FIG. 5, since the main body is integrated, the number of parts is reduced, and it can be manufactured at a lower price than in the case of FIG.

[0024]

EXAMPLE An optical waveguide module having 16 circuits was manufactured in the embodiment shown in FIG. 1, and the transmission loss of each port as an optical waveguide and the transmission loss of each circuit when the optical waveguide module was formed were measured. . The optical waveguide was a mode combiner shown in FIG. 4, and the groove of the optical fiber array had a V-shaped cross section. The grooves of the optical fiber array were processed with a dicer. FIG. 3 is a graph showing the results. The transmission loss of each port of the optical waveguide indicated by a black circle is 2
Although there is a difference of not less than dB, in the optical waveguide module shown by a white circle, the difference in transmission loss of each circuit is reduced to about 0.5 dB and is made uniform.

[0025]

According to the optical waveguide module of the present invention, an optical waveguide and an optical fiber array are connected, and a difference in regular transmission loss between the ports of the optical waveguide is compared with the port of the optical waveguide at the connecting portion. Since the difference in the transmission loss of each circuit as the optical waveguide module is made smaller than the difference in the transmission loss between the ports of the optical waveguide, compensation is made by the deviation of the optical axis of the optical fiber array from the optical fiber. The transmission loss of each circuit is equalized as a waveguide module,
It does not require special electrical compensation and can be used in optical systems.

Also, the optical fiber array is provided with a plurality of optical fibers inserted and fixed in a plurality of grooves arranged in parallel with the surface of the base, and the maximum value of the transmission loss of each port of the optical waveguide and the If the position of each groove is displaced in the direction in which the grooves are arranged in accordance with the amount of optical axis shift that causes a coupling loss corresponding to the difference in transmission loss of the optical fiber, the amount of the optical axis shift corresponding to the optical fiber is reduced. That is, it is possible to accurately give the displacement, and it is easy to manufacture the optical fiber array.

[Brief description of the drawings]

1A and 1B are diagrams illustrating an embodiment of an optical waveguide module according to the present invention, wherein FIG. 1A is a plan view of the optical waveguide, FIG. 1B is a front view of the optical waveguide, and FIG. FIG. 4D is a front view, FIG. 4D is a plan view of the optical fiber array, FIG. 4E is a partially enlarged front view of the optical fiber array, and FIG. 4F is a plan view of the optical waveguide module.

FIG. 2 is a graph showing a relationship between a coupling loss and an optical axis shift amount.

FIG. 3 is a graph showing a transmission loss of each port of the optical waveguide and a transmission loss of each circuit as the optical waveguide module in the embodiment of the optical waveguide module according to the present invention.

4A and 4B are diagrams illustrating a mode combiner and an optical connector, which are examples of an optical waveguide, wherein FIG. 4A is a perspective view, and FIG.
3 is a plan view, and FIG. 3C is an enlarged view of a main part of the mode combiner.

FIG. 5 is a perspective view illustrating a method of integrally manufacturing the optical waveguide and the optical fiber array of the optical waveguide module.

[Explanation of symbols]

 1: Optical waveguide 1a: Port 2: Optical fiber array 2a: Base 2b: Groove 2c: Optical fiber 2d: Holding plate 3: Tape-shaped optical fiber core wire 4: Coupling part 5: Main body part 5a: Optical waveguide part 5b: Optical fiber arranging portion 5c: Single-core optical fiber mounting portion 5d, 5e: Groove 6: Tape-shaped optical fiber core wire 6a: Optical fiber 7: Single-core optical fiber core wire 8, 9: Holding plate 10: Coupling portion

Claims (3)

[Claims] An optical waveguide module in which an optical waveguide having a plurality of ports and an optical fiber array in which a plurality of optical fibers are arrayed are coupled, wherein a difference in a regular transmission loss between the ports of the optical waveguide is reduced. Compensation is performed by the displacement of the optical axis between the port of the optical waveguide and the optical fiber at the joint between each port and the corresponding optical fiber tip surface, and the difference in transmission loss of each circuit as the optical waveguide module is determined by the port of the optical waveguide. An optical waveguide module characterized in that the difference is smaller than the difference in transmission loss between the two. 2. A method of manufacturing an optical waveguide module in which an optical waveguide having a plurality of ports and an optical fiber array in which a plurality of optical fibers are arranged are combined, wherein a transmission loss of each port of the optical waveguide is determined in advance. Measurement, the loss difference obtained by subtracting the transmission loss of each port from the maximum value of the transmission loss is obtained for each port, and the loss difference is calculated based on data indicating the relationship between the predetermined coupling loss and the optical axis shift amount. The amount of optical axis shift that gives a corresponding coupling loss is determined for each port, and the position of each optical fiber of the optical fiber array is displaced in accordance with the amount of optical axis shift to manufacture an optical fiber array, and the optical waveguide is manufactured. A method for manufacturing an optical waveguide module, comprising coupling a waveguide and the optical fiber array. 3. The optical fiber array, wherein optical fibers are respectively inserted and fixed in a plurality of grooves arranged in parallel with the surface of the base, and the arrangement interval of the grooves is adjusted to the optical axis shift amount. 3. The method for manufacturing an optical waveguide module according to claim 2, wherein the optical waveguide module is manufactured according to the following conditions.