Patent ID: 11923909
Assignee: BEIJING ZHONGKE GUOGUANG QUANTUM TECHNOLOGY CO., LTD.
Field: Telecommunications (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 3:
4. The self-coherent receiver based on polarization-independent delay interferometers according to claim 1, wherein the first polarization-independent delay interferometer comprises a first polarization beam splitter, a first 45° polarization-rotation structure, a second 45° polarization-rotation structure, a fifth polarization beam splitter, a sixth polarization beam splitter, a third long-arm optical fiber, a third short-arm optical fiber;
the first polarization beam splitter is configured to split the first signal light component to a first polarized signal light component and a second polarized signal light component;
the first 45° polarization-rotation structure and the second 45° polarization-rotation structure are respectively configured to rotate a polarization state of each of the first polarized signal light component and the second polarized signal light component by 45° correspondingly;
the fifth polarization beam splitter is configured to transmit a horizontal polarization component of the first polarized signal light component to the third short-arm optical fiber, and reflect a vertical polarization component of the first polarized signal light component to the third long-arm optical fiber; the sixth polarization beam splitter is configured to transmit a horizontal polarization component of the second polarized signal light component to the third short-arm optical fiber, and reflect a vertical polarization component of the second polarized signal light component to the third long-arm optical fiber;
the sixth polarization beam splitter is further configured to perform a polarization interference on the horizontal polarization component of the first polarized signal light component transmitted through the third short-arm optical fiber and the vertical polarization component of the first polarized signal light component transmitted through the third long-arm optical fiber, to generate a first polarization interference optical signal; the fifth polarization beam splitter is further configured to perform a polarization interference on the horizontal polarization component of the second polarized signal light component transmitted through the third short-arm optical fiber and the vertical polarization component of the second polarized signal light component transmitted through the third long-arm optical fiber, to generate a second polarization interference optical signal;
the first 45° polarization-rotation structure and the second 45° polarization-rotation structure are further respectively configured to rotate a polarization state of each of the second polarization interference optical signal and the first polarization interference optical signal by 45° correspondingly;
the first polarization beam splitter is further configured to combine a horizontal polarization component of the first polarization interference optical signal and a horizontal polarization component of the second polarization interference optical signal, to generate the first interference optical signal; and the first polarization beam splitter is further configured to combine a vertical polarization component of the first polarization interference optical signal and a vertical polarization component of the second polarization interference optical signal, to generate the second interference optical signal;
the second polarization-independent delay interferometer comprises a third polarization beam splitter, a third 45° polarization-rotation structure, a fourth 45° polarization-rotation structure, a seventh polarization beam splitter, an eighth polarization beam splitter, a fourth long-arm optical fiber, a fourth short-arm optical fiber and a second phase shifter;
the third polarization beam splitter is configured to split the second signal light component to a third polarized signal light component and a fourth polarized signal light component;
the third 45° polarization-rotation structure and the fourth 45° polarization-rotation structure are respectively configured to rotate a polarization state of each of the third polarized signal light component and the fourth polarized signal light component by 45° correspondingly;
the seventh polarization beam splitter is configured to transmit a horizontal polarization component of the third polarized signal light component to the fourth short-arm optical fiber, and reflect a vertical polarization component of the third polarized signal light component to the fourth long-arm optical fiber; the eighth polarization beam splitter is configured to transmit a horizontal polarization component of the fourth polarized signal light component to the fourth short-arm optical fiber, and reflect a vertical polarization component of the fourth polarized signal light component to the fourth long-arm optical fiber;
the second phase shifter is configured to adjust a phase of an optical signal passing the fourth short-arm optical fiber, so that a phase difference between the optical signal passing the fourth short-arm optical fiber and an optical signal passing the fourth long-arm optical fiber is π/2;
the eighth polarization beam splitter is further configured to perform a polarization interference on the horizontal polarization component of the third polarized signal light component transmitted by the fourth short-arm optical fiber and the vertical polarization component of the third polarized signal light component transmitted by the fourth long-arm optical fiber to generate a third polarization interference optical signal; the seventh polarization beam splitter is further configured to perform a polarization interference on the horizontal polarization component of the fourth polarized signal light component transmitted by the fourth short-arm optical fiber and the vertical polarization component of the fourth polarized signal light component transmitted by the fourth long-arm optical fiber to generate a fourth polarization interference optical signal;
the third 45° polarization-rotation structure and the fourth 45° polarization-rotation structure are further respectively configured to rotate a polarization state of each of the fourth polarization interference optical signal and the third polarization interference optical signal by 45° correspondingly;
the third polarization beam splitter is further configured to combine the horizontal polarization component of the third polarization interference optical signal and the horizontal polarization component of the fourth polarization interference optical signal to generate the third interference optical signal; and to combine the vertical polarization component of the third polarization interference optical signal and the vertical polarization component of the fourth polarization interference optical signal to generate the fourth interference optical signal.