Patent ID: 11880116
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 13:
14. The method according to claim 8, further comprising:
splitting, by a second splitter, a single light beam into two equal light beams and inputting a first light beam of the two equal light beams to the first splitter;
combining, by a coupler, the combined light beam output from the combiner and a second light beam of the two equal light beams output from the second splitter into a second combined light beam, splitting the second combined light beam into two equal light beams of the coupler, and outputting the two equal light beams of the coupler;
converting, by a first photodetector, a first light beam of the two equal light beams output by the coupler into a first electrical signal;
converting, by a second photodetector, a second light beam of the two equal light beams output by the coupler into a second electrical signal;
obtaining, by a subtractor, a difference between the first and the second electrical signals output from the first and the second photodetectors; and
adjusting a second phase shifter such that a phase difference between the combined light beam output from the combiner and the second light beam of the two equal light beams output from the second splitter is π/2.