JPH11119042A - Planar waveguide device with segmented waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust attenuation of a light signal by addition of a simple structure body by providing a segment waveguide having at least one break of a waveguide causing the intensity attenuation of a small light signal in the waveguide. SOLUTION: This element consists of a plane substrate 100, a branch waveguide 110 with a branch path, and segment waveguides 120. The segment waveguides 120 correct the unequal branching ratio of waveguide light signals or an output difference between the waveguides to obtain the equal branching ratio of the waveguides or the equal output between the waveguides. The segment waveguides 120 are formed of gaps as breaks of optical waveguides for generating smaller intensity attenuation than the light signal intensity in the waveguides, i.e., a discontinuous array of segmented optical waveguides. The segment waveguides 120 need to have at least one break, and two adjacent breaks form a segment to prescribe the input/output end surface along the optical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar waveguide device having a branch waveguide, and more particularly to a planar waveguide device having a uniform branch ratio of a waveguide or a uniform output between waveguides.

[0002]

2. Description of the Related Art Integration of an optical device for manufacturing an optical waveguide on a flat substrate using a planar waveguide technology for the purpose of optical signal processing such as branching, modulation, switching, signal multiplexing, and equalization of an optical signal. Much research has been done on technology. Techniques required for manufacturing an optical waveguide device for an optical communication system are broadly classified into waveguide design, manufacturing, and packaging.

Depending on the purpose of the optical waveguide device, it may be necessary to make the shape of the waveguide asymmetric when branching an optical signal, or to make the traveling path differ.
In manufacturing such a waveguide or performing a packaging process, signal intensity attenuation and other signal attenuation are inevitably generated. In such a case, particularly in the case of an element using a Y-branch point, the characteristic of accurately branching the branch ratio is very important. In the case of an element having an asymmetric structure using a Y-branch point, it is necessary to adjust such a branching ratio artificially. Conventionally, in mass production, there is no special technique capable of solving such a problem, and the branch ratio can be adjusted by individual manual adjustment. FIG. 4 shows an example of an asymmetric optical waveguide device. Reference number 100 is a flat substrate, 130
Denotes an asymmetric waveguide.

Generally, in the manufacture of an asymmetric optical waveguide device, a difference in output optical signal is inevitably generated for each branched waveguide due to a difference in a path where an optical signal travels or a difference in the degree of signal attenuation. Other factors also cause unequal branch ratios or output differences of the optical waveguide device. Therefore, when it is necessary to match the branching ratio and the intensity of the output optical signal in an optical waveguide element having a structure including an asymmetrical waveguide, an artificial element using an existing optical signal attenuator or an additional element of a filter is used. Adjustment was required. For this reason, there are disadvantages that the cost is increased due to the use of the added element, the time cost is increased due to the alignment of the additional element and the waveguide element, the equipment is added, and the cost for modularizing various elements is generated. there were.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and to provide a uniform branching ratio or an equal output by correcting an uneven branching ratio or an output difference of an optical waveguide element. A plane having a segmented waveguide, which does not require an additional step or an additional step accuracy in the step of manufacturing the optical waveguide element, and eliminates an additional cost factor in realizing this. It is to provide a waveguide element.

[0006]

According to a first aspect of the present invention, there is provided a planar waveguide device having a segmented waveguide, comprising: a branch waveguide; Comprises a segmented waveguide for adjusting the intensity attenuation of the output signal of each waveguide and making the output intensity of the optical signal between the waveguides uniform, wherein the segmented waveguide has a small light intensity in the waveguide. The optical waveguide is characterized by having at least one break in the optical waveguide that causes signal intensity attenuation.

In addition, the optical signal intensity attenuation of the segmented waveguide according to the present invention is adjusted by the number of segments included in each waveguide, the distance between segments in one waveguide, and the degree of offset between segments. .

[0008]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. The present invention includes a simple structure inside the waveguide that attenuates the optical signal during fabrication of the waveguide. In addition, the present invention makes the overall output signal strength attenuation of all output waveguides uniform while maintaining the same process and the same accuracy when manufacturing the waveguide. FIG. 1 shows a structure of an asymmetric optical waveguide device including a structure of a waveguide having an equal branching ratio according to a preferred embodiment of the present invention, wherein reference numeral 100 is a planar substrate, 110 is a waveguide having a branch, and 120 is a waveguide. 3 shows a plurality of segmented waveguides.

The segmented waveguide 120 compensates for an unequal branch ratio of the waveguide optical signal or an output difference between the waveguides, thereby obtaining a uniform branch ratio of the waveguides or a uniform output between the waveguides. I do. The segmented waveguide 120 is formed by forming a gap due to interruption of the optical waveguide to generate an intensity attenuation smaller than the optical signal intensity inside the waveguide, that is, a discontinuous arrangement of segmented optical waveguides. The segment waveguide may have at least one break, but two adjacent breaks form a segment and define an input / output end face in the optical axis direction.

This is to adjust the output signal intensity attenuation between the waveguides at the output end waveguide of the waveguide element manufactured on a single plane, and to make the intensity of the optical signal between the waveguides uniform. .

In designing an asymmetric waveguide, in order to adjust the output of all waveguides within a certain range, all or one of the other waveguides is determined based on the output signal strength attenuation of the branch waveguide having the lowest output. The part is manufactured as a segment waveguide.
FIG. 2 shows various structures of the segment waveguide 120. The attenuation of the waveguide output is controlled by adjusting the number of segments constituting the segment waveguide included in each branch waveguide and the gap between the segments. Adjust according to the distance and the degree of distortion between segments.

For this purpose, the segmented waveguide 120 has a structure in which signal attenuation occurs between the waveguide and adjacent segments or between mutually adjacent segments. Further, the segment waveguide 120 has a structure in which the optical axis is inclined or tilted or the optical axis is offset between segments adjacent to the waveguide or between adjacent segments.

A material such as a cladding or a material having a refractive index smaller than the refractive index of the segment is used in the gap between each segment or between the waveguide and the segment.

In the waveguide element constructed as described above, the structure and arrangement of the segments are arranged in descending order of the attenuation with reference to the branch waveguide having the largest output signal intensity attenuation, and the signal attenuation is adjusted to the reference value. So that the attenuation characteristics of all the waveguides are the same.

Further, in order to reduce the reflection loss caused by the existence of the segment waveguide, if necessary, it may be manufactured by adjusting the inclination angle of the end face in the optical axis direction which is the input / output surface of the segment. FIG. 3 shows an example in which the waveguide is subjected to an arbitrary angle processing to reduce the reflection loss. Reference numeral 140 denotes a segment waveguide having a segment whose input / output surface is inclined by a predetermined angle θ with respect to a direction perpendicular to the optical axis. The inclination angle θ is preferably in the range of 0 ° ≦ θ ≦ 20 °.

Note that the waveguide and the segment waveguide are manufactured simultaneously using the same process.

[0017]

According to the present invention, an optical signal is attenuated by the addition of a simple structure at the same time as the manufacture of a waveguide. Can be adjusted, so that an additional step or additional adjustment is not required. Further, there is no need for an additional step or artificial effort in packaging and mounting, and there is another effect that the cost can be reduced when manufacturing an element having the same function.

[Brief description of the drawings]

FIG. 1 illustrates a structure of an asymmetric optical waveguide device including a structure of a waveguide having an equal branching ratio according to a preferred embodiment of the present invention.

FIG. 2 illustrates a structure of a segmented waveguide according to a preferred embodiment of the present invention.

FIG. 3 shows a structure of a waveguide having segmented waveguides having arbitrary angles to reduce reflection loss.

FIG. 4 shows an example of an asymmetric optical waveguide device.

[Explanation of symbols]

 100 Planar substrate 110 Branch waveguide 120 Segment waveguide 130 Asymmetric branch waveguide 140 Segment waveguide with arbitrary inclination angle (θ)

Claims (7)

[Claims] 1. A planar waveguide device having a branch waveguide, wherein said waveguide device adjusts the intensity attenuation of an output signal of each waveguide and equalizes the output intensity of an optical signal between said waveguides. A segmented waveguide, wherein the segmented waveguide has at least one break in the optical waveguide that causes a small optical signal intensity attenuation in the waveguide.
A planar waveguide device, comprising: 2. The planar waveguide device according to claim 1, wherein the segment waveguide has a structure in which signal attenuation occurs between the waveguide and a segment adjacent thereto. 3. The planar waveguide device according to claim 1, wherein the segment waveguide has a structure in which signal attenuation occurs between mutually adjacent segments. 4. The segment waveguide according to claim 1, wherein the segment waveguide has a structure in which the optical axis is tilted or offset between the waveguide and a segment adjacent thereto or a segment adjacent to each other. Planar waveguide device. 5. The planar waveguide device according to claim 1, wherein the waveguide and the segment waveguide are manufactured simultaneously using the same process. 6. An end of the waveguide or both ends of one or more segments of the segmented waveguide are inclined at a predetermined angle θ with respect to a direction perpendicular to an optical axis, and the angle θ is 0 ° ≦ θ.
2. The planar waveguide device according to claim 1, wherein the angle is in a range of ≤20 °. 7. The planar waveguide device according to claim 1, wherein the signal intensity of the segment waveguide is adjusted by adjusting the number of segments.