Patent ID: 11949461
Assignee: BEIJING ZHONGKE GUOGUANG QUANTUM TECHNOLOGY CO., LTD.
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 2:
3. The integrated self-coherent receiving optical chip based on round-trip delay interferometers according to claim 1, wherein, the first round-trip delay interferometer comprises a second beam splitter, a ninth optical waveguide, a tenth optical waveguide, a seventh polarization beam splitting rotator and a eighth polarization beam splitting rotator,
a length difference between the ninth optical waveguide and the tenth optical waveguide is half of an arm length difference of the first round-trip delay interferometer;
the second beam splitter is configured to split the first signal light component to generate a first component and a second component with a same amplitude;
two output ports of the seventh polarization beam splitting rotator are directly connected by an optical waveguide, and are configured to reflect the first component from a first input port of the seventh polarization beam splitting rotator, and change a horizontal polarization component and a vertical polarization component of the first component into the vertical polarization component and the horizontal polarization component of the first component, respectively;
two output ports of the eighth polarization beam splitting rotator are directly connected by another optical waveguide, and are configured to reflect the second component from one of input ports of the eighth polarization beam splitting rotator, and change a horizontal polarization component and a vertical polarization component of the second component into the vertical polarization component and the horizontal polarization component of the second component, respectively;
the second beam splitter is further configured to interfere the reflected first component and the reflected second component to generate the first interference optical signal and the second interference optical signal;
the second round-trip delay interferometer comprises a third beam splitter, an eleventh optical waveguide, a twelfth optical waveguide, a second quarter-wave plate, and the seventh polarization beam splitting rotator and the eighth polarization beam splitting rotator shared with the first round-trip delay interferometer,
an angle between a main axis of the second quarter-wave plate and a horizontal direction is 0°;
a length difference between the eleventh optical waveguide and the twelfth optical waveguide is half of an arm length difference of the second round-trip delay interferometer;
the third beam splitter is configured to split the second signal light component to generate a third component and a fourth component with a same amplitude;
the seventh polarization beam splitting rotator is further configured to reflect the third component from a second input port of the seventh polarization beam splitting rotator, and change a horizontal polarization component and a vertical polarization component of the third component into the vertical polarization component and the horizontal polarization component of the third component, respectively;
the eighth polarization beam splitting rotator is further configured to reflect the fourth component from a second input port of the eighth polarization beam splitting rotator, and change a horizontal polarization component and a vertical polarization component of the fourth component into the vertical polarization component and the horizontal polarization component of the fourth component, respectively;
the another optical waveguide directly connecting the two output ports of the eighth polarization beam splitting rotator is also provided with the second quarter-wave plate configured to increase the fourth component by π/2 phase, and not increase a phase of the third component; and
the third beam splitter is further configured to interfere the reflected third component and the reflected fourth component to generate the third interference optical signal and the fourth interference optical signal.