PLANE OPTICAL WAVEGUIDE TYPE MACH-ZEHNDER CIRCUIT, AND PLATE OPTICAL WAVEGUIDE CIRCUIT AND OPTICAL MULTIPLEXER/ DEMULTIPLEXER USING THE PLANE OPTICAL WAVEGUIDE TYPE MACH-ZEHNDER CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a plane optical waveguide type Mach-Zehnder circuit which can suppress a variation in a peak wavelength, and the increase in insertion loss and the polarization dependency loss associated with the variation.;SOLUTION: A first optical waveguide 3 and a second optical waveguide 4 are juxtaposed, and a first directional coupled part 1 and a second directional coupled part 2 are formed by bring the first optical waveguide 3 near to the second optical waveguide 4. The first directional coupled part 1 and the second directional coupled part 2 are spaced in the longitudinal direction of the optical waveguide with each other. The length of the first optical waveguide 3 lying between the first directional coupled part 1 and the second directional coupled part 2 differs from the length of the second optical waveguide 4 lying between the part 1 and the part 2. An uncoupled core part 5 which does not practically generate optical coupling with a propagated light beam is provided at least in the vicinity of both sides of the side part along the longitudinal direction of the first optical waveguide 3 and the second optical waveguide 4 both lying between the first directional coupled part 1 and the second directional coupled part 2, at a constant space from the first optical waveguide 3 and the second optical waveguide 4.;COPYRIGHT: (C)2002,JPO