Patent ID: 11888531
Assignee: BEIJING ZHONGKE GUOGUANG QUANTUM TECHNOLOGY CO., LTD.
Field: Telecommunications (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 11:
12. The polarization independent DQPSK demodulation integrated optical chip according to claim 9, wherein the first optical waveguide is provided with a fourth beam splitter and a fifth beam splitter, the second optical waveguide is provided with a sixth beam splitter and a seventh beam splitter;
two output ports of the fourth beam splitter are respectively connected to two input ports of the fifth beam splitter through fifth optical waveguides to form a third equal arm interferometer; two output ports of the sixth beam splitter are respectively connected to two input ports of the seventh beam splitter through sixth optical waveguides to form a fourth equal arm interferometer;
a second polarization rotating optical waveguide is provided on each of seventh optical waveguides of upper arms of the third equal arm interferometer and the fourth equal arm interferometer; a third polarization rotating optical waveguide is provided on each of eighth optical waveguides of lower arms of the third equal arm interferometer and the fourth equal arm interferometer;
the second polarization rotating optical waveguide is composed of a second half wave plate optical waveguide and a second faraday rotatory waveguide, which are connected in sequence, an angle between a main axis direction of the second half wave plate optical waveguide and a horizontal direction is 22.5°, and a polarization rotation angle of the second faraday rotatory waveguide is 45°;
the third polarization rotating optical waveguide is composed of a third faraday rotatory waveguide and a third half wave plate optical waveguide, which are connected in sequence, a polarization rotation angle of the third faraday rotatory waveguide is 45°, an angle between a main axis direction of the third half wave plate optical waveguide and the horizontal direction is −22.5°;
the second polarization rotating optical waveguide is configured to rotate polarization of an optical signal passing in a forward direction by 180° and rotate polarization of an optical signal passing in a reverse direction by 90°;
the third polarization rotating optical waveguide is configured to rotate polarization of an optical signal passing in a forward direction by 180° and rotate polarization of an optical signal passing in a reverse direction by −90°;
the third equal arm interferometer is configured such that the first signal optical component incident from one of two input ports of the fourth beam splitter emits from an output port of the fifth beam splitter, and such that the first interference optical signal incident from the output port of the fifth beam splitter emits from one of the two input ports of the fourth beam splitter;
the fourth equal arm interferometer is configured such that the second signal optical component incident from one of two input ports of the sixth beam splitter emits from an output port of the seventh beam splitter, and such that the third interference optical signal incident from the output port of the seventh beam splitter emits from one of the two input ports of the sixth beam splitter.