CPC G02B 6/29355 (2013.01) [G02B 6/2938 (2013.01)] | 15 Claims |
1. A wavelength division multiplexer and demultiplexer, comprising:
a waveguide structure, comprising:
a first-stage Mach-Zehnder interferometer (MZI) structure having two input terminals and two output terminals, wherein one of the input terminals is configured to receive an input optical beam with a first center wavelength and a second center wavelength, and wherein the output terminals are configured to transmit one first-stage output optical beam with the first center wavelength and another first-stage output optical beam with the second center wavelength, respectively; and
two second-stage MZI structures, wherein one input terminal of one of the second-stage MZI structures and one input terminal of the other second-stage MZI structure are configured to respectively receive the first-stage output optical beams, one output terminal of one of the second-stage MZI structures and one output terminal of the other second-stage MZI structure are configured to transmit one second-stage output optical beam with the first center wavelength and another second-stage output optical beam with the second center wavelength, respectively, and each second-stage MZI structure is configured in cross-state condition such that the one second-stage output optical beam and the one first-stage output optical beam are not in the same optical waveguide path, the another second-stage output optical beam and the another first-stage output optical beam are not in the same optical waveguide path, and no optical beam is outputted through an other output terminal of each second-stage MZI structure.
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