OPTICAL WAVEGUIDE TYPE PART

摘要

PURPOSE:To prevent the fluctuation of insert loss, branching ratio and quenching ratio in the function part of an optical waveguide even when the ambient temperature of an optical waveguide type part is changed. CONSTITUTION:An optical waveguide 4 is formed on the main face 1a side of an optical waveguide base 1 consisting of a ferroelectric crystal. The optical waveguide 4 has at least one function part 4b for branching or coupling a light. The spontaneous polarizing direction A in the ferroelectric crystal crosses the advancing direction of the light. A first crystal face 1b and a second crystal face 1c for generating mutually opposite charges in the optical waveguide base 1 are present on the optical waveguide base 1. A first conductive film 6a is formed in one area 5A extending from the boundary between the first crystal face 1b and the main face 1a to the function part 4b. A second conductive film 6c is formed in the other area 5B extending from the boundary between the second crystal face 1c and the main face 1a to the function part 4b. The first conductive film 6a and the second conductive film are electrically continued to each other.