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

Claim 5:
6. The polarization independent DQPSK demodulation integrated optical chip according to claim 5, wherein the first optical waveguide is provided with a third polarization beam splitter rotator and a fourth polarization beam splitter rotator, the second optical waveguide is provided with a fifth polarization beam splitter rotator and a sixth polarization beam splitter rotator,
two output ports of the third polarization beam splitter rotator are respectively connected to two input ports of the fourth polarization beam splitter rotator through fifth optical waveguides to form a first equal arm interferometer; two output ports of the fifth polarization beam splitter rotator are respectively connected to two input ports of the sixth polarization beam splitter rotator through sixth optical waveguides to form a second equal arm interferometer;
a notch groove is provided on seventh optical waveguides perpendicular to four arms of the first equal arm interferometer and the second equal arm interferometer;
a half wave plate and faraday rotatory plate, which are aligned and fitted with each other, are inserted into the notch groove, an angle between a main axis of the half wave plate and a horizontal direction are 22.5″, and a polarization rotation angle of the faraday rotatory plate is 45°:
the half wave plate and the faraday rotatory plate are configured to rotate polarization of an optical signal passing in a reverse direction by 90°, and maintain a polarization state of an optical signal passing in a forward direction unchanged;
the first equal arm interferometer is configured such that the first signal optical component incident from one of two input ports of the third polarization beam splitter rotator emits from an output port of the fourth polarization beam splitter rotator, and such that the first interference optical signal incident from the output port of the fourth polarization beam splitter rotator emits from one of the two output ports of the third polarization beam splitter rotator;
the second equal arm interferometer is configured such that the second signal optical component incident from one of the two output ports of the fifth polarization beam splitter rotator emits from the output port of the sixth polarization beam splitter rotator, and such that the third interference optical signal incident from the output port of the sixth polarization beam splitter rotator emits from one of the two output ports of the fifth polarization beam splitter rotator.