JP2000206351A - Substrate waveguide optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the material cost and manhour of an array by opening both an input waveguide and an output waveguide to the same one side of a polygonal substrate. SOLUTION: Both an inlet waveguide 22A and an output waveguide 22B are opened to the same one side of a substrate 10. That is, the input waveguide 22A which has opened to the left CD side in the drawing heretofore, is turned in a direction 180-degree arc to be opened to the EF side. As a matter of course, the waveguide of the direction turning part has such a radius of curvature not to cause radiation loss and inhibit the occurrence of unnecessary mode to the utmost. Accordingly, the output waveguide 22B and the input waveguide 22A are arranged side by side on the EF side. In connection to an external circuit, one optical fiber array 30 is aligned and fixed to the EF side by adhesion. In this case, opening means that the core end face of the input waveguide 22A, for example, appears on the CD side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate waveguide type optical device.

[0002]

2. Description of the Related Art FIG. 3A shows an example of a substrate waveguide type optical splitter. Reference numeral 10 denotes a substrate made of, for example, silicon, quartz, or the like. Usually, it is a rectangular thin plate. In this case, a waveguide circuit 20 of a 1 × 8 splitter is formed on the upper surface. The input waveguide 22A (corresponding to the core of the optical fiber) of the waveguide circuit 20 is open on the CD side surface of the rectangular substrate 10. The output waveguide 22B (corresponding to the core of the optical fiber) is open on the EF side surface. This substrate is formed by depositing a raw material of an optical fiber on a silicon substrate and sintering the waveguide pattern by reactive ion sputtering or the like using a reactive ion sputtering (FDH) method. Core pattern). This FDH method is well known and will not be described in detail. Usually, a plurality of circuits are formed on a single substrate, and are divided into a plurality of circuits.

In FIG. 1, the left side is the input side, and the right side is the output side. However, the following description has all referred to the left as the input side.

[0004] The above-mentioned "CD side surface" means the left side surface in Fig. 1 (a).
0 means the side surface including the side CD of the upper surface. The EF side and the DF side described later have the same meaning.

[0005] Further, the number of input waveguides 22A may be plural instead of one.

Reference numeral 30A in FIG. 3B denotes an optical fiber array on the input side. The optical fiber 34 is housed in a V-groove on the optical fiber mounting member 32 and is fixed together with the holding plate 36 with an adhesive.

Reference numeral 30B denotes an output side optical fiber array component. Also in this case, the optical fiber 34 is placed in a plurality of V-grooves (the same pitch as the arrangement of the cores of the output waveguide 22B) on the optical fiber mounting member 32, and is fixed together with the holding plate 36 with an adhesive. The optical fiber array is a component necessary for positioning and connecting the core of the external optical fiber and the optical waveguide. The material of the member 32 is, for example, quartz,
Glass, ceramics, other resins, and the like can be used.

The CD side and the EF side of the substrate 10 and the end faces of the input side array 30A and the output side array 30B are obliquely ground. Then, the core is aligned while monitoring each light, and connected and fixed with an adhesive or the like. Usually, it is then implemented in a package.

FIG. 4A shows an arrayed waveguide diffraction grating (hereinafter referred to as A) which is a quartz-based planar substrate type waveguide as described above.
WG). 24 has a so-called lens action,
A slab waveguide 26 diffractively couples the output light of the input waveguide to the array waveguide. Reference numeral 26 denotes a group of array waveguides having different lengths so as to generate an optical path difference by a required resolution. Also in this case, the input waveguide 22A is open on the CD side surface of the rectangular substrate 10. Also, in order to make the drawing easier to see, the number of output waveguides 22B and the number of array waveguides 26 are not matched. Although the case where there is one input waveguide 22A is shown,
There may be more than one. The output waveguide 22B is EF
Open to the side.

Also in this case, the CD side of the substrate 10 and E
F side, input side array 30A and output side array 30B
Is ground obliquely, aligned while monitoring each light, and connected and fixed with an adhesive or the like.

[0011]

On the input and output sides, separate optical fiber arrays (the number of applied cores, that is, the number of V-grooves may be different) are prepared. Alignment was performed separately and fixed by bonding or the like.
Therefore, manufacturing a single substrate waveguide type optical device requires a lot of man-hours and material costs, and there is a limit to cost reduction. In optical circuits such as optical splitters and AWGs that are currently used in many cases, one side (input side or output side) often has a single core. For this single fiber side optical fiber array, it is conceivable to optimize the width and reduce the material cost,
When the size of the array is reduced, the adhesive strength with the substrate 10 is weak, and the array cannot be put to practical use. Therefore, there was a problem that it had to be enlarged. At the time of initial array alignment, there is no array on the opposite side, so to locate the core of the optical fiber, it is mechanically positioned with reference to one side or one point of the substrate, so there is a problem of positioning accuracy and a great deal of There was also a problem that it took time.

[0012]

According to the first aspect of the present invention, as shown in FIGS. 1 and 2, in the above-mentioned substrate waveguide type optical device, both the input waveguide 22A and the output waveguide 22B are provided. The opening is formed on the same one side surface of the substrate 10.

In the above description, "one side surface" means, for example, when the substrate 10 is rectangular, the left side surface, the right side surface, and the like are each "one side surface".

"Open" means, for example, that the core end face of the input waveguide 22A appears on the CD side face.

[0015]

Embodiment 1 This is a case of the optical splitter shown in FIG. Conventionally, the input waveguide 22A, which has been opened on the left side of the CD in the figure, is turned by 180 degrees to be opened on the side of the EF. Naturally, the radius of curvature of the waveguide in the direction change portion is set to a radius of curvature that does not cause radiation loss and minimizes generation of unnecessary modes. From the above, EF
The output waveguide 22B and the input waveguide 22A are arranged side by side.

As shown in FIG. 1 (b), connection to an external circuit requires only one optical fiber array 30 to be centered and adhered and fixed to the EF side as described above.

[0017]

[Embodiment 2] FIG. 2A shows the case of an AWG type optical multiplexer. Input waveguide 22A, Output waveguide 22
B is also lowered straight down in the figure, and the tip is opened on the DF side surface. The array waveguide 26 is curved in a fan shape as in the related art in order to provide an optical path difference. The output waveguide 22B and the input waveguide 22A are arranged on the DF side surface.

As shown in FIG. 2 (b), connection to an external circuit requires only one optical fiber array 30 to be aligned and adhered and fixed to the side surface of the DF as described above.

The present invention is not limited to quartz-based waveguides, but can be applied to other types of planar substrate waveguides. The other system is, for example, a compound semiconductor system or a polymer system.

[0020]

According to the present invention, since only one optical fiber array is required, the material cost and man-hour of the array can be reduced to about 1/2. The single core size problem is also solved at the same time. With one alignment and bonding, the input side and the output side can be performed at the same time, and this process can be performed with half the man-hour. Although the bonded portion is a bottleneck in reliability, since only one bonded portion is provided, the reliability is improved and the variation can be reduced. Since the array is connected in only one direction, the size of the entire module (package size) can be reduced. In particular, in the case of AWG, the waveguide itself becomes smaller, which leads to cost reduction of the substrate 10.

[Brief description of the drawings]

1A and 1B are explanatory diagrams of the present invention according to a first embodiment, wherein FIG. 1A is a plan view of a substrate 10, and FIG. 1B shows a state where an optical fiber array 30 is connected.

FIGS. 2A and 2B are explanatory views of the present invention according to a second embodiment, in which FIG. 2A is a plan view of a substrate 10, and FIG. 2B shows a state where an optical fiber array 30 is connected.

FIG. 3 is an explanatory diagram of a conventional technique using an optical splitter as an example.
(A) is a plan view of the substrate 10 and (b) shows a state where the optical fiber array 30 is connected.

FIGS. 4A and 4B are explanatory diagrams of a conventional technique using AWG as an example.
2 is a plan view of the substrate 10, and FIG. 2B shows a state where the optical fiber array 30 is connected.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 20 Waveguide circuit 22A Input waveguide 22B Output waveguide 24 Slab waveguide 26 Array waveguide group 30 Optical fiber array 30A Input side array 30B Output side array 32 Optical fiber mounting member 34 Optical fiber 36 Press plate

Claims (1)

[Claims] An input waveguide (2) is provided on a polygonal substrate (10).
2A and an output waveguide 22B are formed, and the input waveguide 22A and the output waveguide 22 are formed.
At B, it is connected to an external optical circuit.
In the substrate waveguide type optical device, the input waveguide 22
A and the output waveguide 22B are both
A substrate waveguide type optical device, characterized in that it is opened on the same one side face of the substrate waveguide.