Patent ID: 7978401
Filing Date: 2011-07-12
Classification: G02B,H04B

Abstract:
1. A Planar Lightwave Circuit (PLC) delay demodulation device comprising: a PLC base plate; an input waveguide, which receives DQPSK signals; a Y-shape waveguide, which splits the input waveguide into two waveguides; a first Mach-Zehnder interferometer including a first input coupler, which is connected to one of the two waveguides split by the Y-shape waveguide, a first output coupler, which is connected to output waveguides, and two arm-waveguides having different lengths with respect to each other and connected between the first input coupler and the first output coupler; and a second Mach-Zehnder interferometer including a second input coupler, which is connected to another waveguide split by the Y-shape waveguide, a second output coupler, which is connected to other output waveguides, and two arm-waveguides having different lengths with respect to each other and connected between the second input coupler and the second output coupler, wherein the first Mach-Zehnder interferometer and the second Mach-Zehnder interferometer are disposed bilaterally symmetric to each other on the PLC base plate, each of the two arm-waveguides of the first Mach-Zehnder interferometer crosses each of the two arm-waveguides of the second Mach-Zehnder interferometer once on each side of the PLC base plate, and the two arm-waveguides of the first Mach-Zehnder interferometer and the two arm-waveguides of the second Mach-Zehnder interferometer cross each other four times.