| 摘要 |
A delay demodulation device, which reduces chip size and polarization dependent frequency (PDf), is provided. The delay demodulation device comprises: an input waveguide, which receives DQPSK signals; a Y-shape waveguide, which splits the input waveguide; a first Mach-Zehnder interferometer; and a second Mach-Zehnder interferometer. Both end of two arm waveguides of first Mach-Zehnder interferometer and both ends of two arm waveguides of second Mach-Zehnder interferometer are angled toward the center portion of a Planar Lightwave Circuit (PLC). Because of the angle, the length of the two arm waveguides of the first Mach-Zehnder interferometer and the length of the two arm waveguides of the second Mach-Zehnder interferometer in Z-direction can be shortened, and input couplers and output couplers of the Mach-Zehnder interferometers in Z-direction can be shortened as well. The area occupied by the Mach-Zehnder interferometers is also reduced.
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