Polarization conversion device

摘要

A polarization conversion device includes: a directional coupler that includes an input side optical waveguide and an output side optical waveguide which are disposed in parallel to each other and each of which has a core. Assuming that a direction in which the input side optical waveguide and the output side optical waveguide face each other is a width direction and a direction perpendicular to the width direction is a height direction in a cross section perpendicular to a longitudinal direction of each of the input side optical waveguide and the output side optical waveguide, and the directional coupler is configured to couple first light guided through the input side optical waveguide to second light guided through the output side optical waveguide, the polarization direction of the second light is perpendicular to that of the first light.

主权项

1. A polarization conversion device, comprising:
a directional coupler that includes an input side optical waveguide and an output side optical waveguide which are disposed in parallel to each other and each of which has a core, wherein assuming that a direction in which the input side optical waveguide and the output side optical waveguide face each other is a width direction and a direction perpendicular to the width direction is a height direction in a cross section perpendicular to a longitudinal direction of each of the input side optical waveguide and the output side optical waveguide, a size of the core of the input side optical waveguide in the height direction is the same as a size of the core of the output side optical waveguide in the height direction, the core of at least one of the input side optical waveguide and the output side optical waveguide is configured to include a rectangular lower core and a rectangular upper core which is disposed on the lower core such that one side surface of the upper core and one side surface of the lower core in the width direction are flush with each other and of which a size in the width direction is smaller than that of the lower core, and the directional coupler is configured to couple first light guided through the input side optical waveguide to second light guided through the output side optical waveguide, a polarization direction of the second light is perpendicular to that of the first light.