Optical waveguide device and method for manufacturing an optical waveguide device
An optical waveguide device includes first and second branching devices and first to fourth distribution optical waveguides that are formed on an optical waveguide substrate including a latticed dummy pattern of a predetermined pitch and that are arranged, in a region where the dummy pattern is removed, so as to be separated from the dummy pattern, and an interval between the first and second distribution optical waveguides at an output point of the first branching device is equal to an interval between the third and fourth distribution optical waveguides at an output point of the second branching device, and a distance between light propagation centers of the first and second branching devices is an integer multiple of the pitch, and at a point where a distance between neighboring distribution optical waveguides becomes maximum, the distance between the neighboring distribution optical waveguides is an integer multiple of the pitch.
1. An optical waveguide device comprising:
a hybrid mixer having a first branching device branching input first light into two light beams and a second branching device branching input fourth light into two light beams; and
a plurality of dummy patterns being arranged as a periodic lattice at a layer where the hybrid mixer is arranged, the dummy pattern having predetermined pitch;
wherein the plurality of dummy patterns are arranged around the hybrid mixer; and
a distance between a light propagation center of the first branching device and a light propagation center of the second branching device is an integer multiple of the pitch of the dummy pattern.
2. The optical waveguide device according to claim 1 , the hybrid mixer further comprising:
first and second distribution optical waveguides being connected to the first branching device, the first distribution optical waveguide outputting as second light one of the two light beams, the second distribution optical waveguide outputting as third light the other of the two light beams;
third and fourth distribution optical waveguides being connected to the second branching device, the third distribution optical waveguide outputting as fifth light one of the two light beams of the fourth light, the fourth distribution optical waveguide;
wherein the second distribution optical waveguide intersects with the third distribution optical waveguide at an intersection portion.
3. The optical waveguide device according to claim 2 , at a point where a distance between neighboring distribution optical waveguides of the first to fourth distribution optical waveguides becomes maximum, each of the distances between the neighboring distribution optical waveguides is an integer multiple of the pitch of the dummy pattern.
4. The optical waveguide device according to claim 3 , wherein at the point where the distance between the neighboring distribution optical waveguides becomes maximum, all distances between the neighboring distribution optical waveguides are equal to each other.
5. The optical waveguide device according to claim 3 wherein the first to fourth distribution optical waveguides are arranged such that points where respective distances between the neighboring distribution optical waveguides become maximum are positioned on center lines that are among center lines of the dummy pattern and that are parallel with light propagation directions of the first to fourth distribution optical waveguides.
6. The optical waveguide device according to claim 3 , wherein straight optical waveguides are additionally provided in the first to fourth distribution optical waveguides.
7. The optical waveguide device according to claim 3 , wherein the first to fourth distribution optical waveguides are arranged such that points where respective distances between the neighboring distribution optical waveguides become maximum are separated by half of the pitch in directions perpendicular to light propagation directions of the first to fourth distribution
optical waveguides from center lines that are among center lines of the dummy pattern and that are parallel with the light propagation directions.
8. The optical waveguide device according to claim 3 , wherein the optical waveguide device is structured by silicon waveguides formed on a silicon substrate.