Patent ID: 11885742
Assignee: NEC CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 8:
9. A receiver comprising:
a divider configured to divide an optical signal transmitted for detecting a detection target on a traveling path over a plurality of paths, including a first path, a second path, a third path, a fourth path, and a fifth path;
a detector configured to detect a received light intensity of the optical signal at a first position of the first path where the received light intensity becomes maximum, and at more than three positions out of a second position of the second path where the received light intensity increases when an optical axis of the optical signal is shifted in an upper right direction, a third position of the third path where the received light intensity increases when the optical axis of the optical signal is shifted in a lower right direction, a fourth position of the fourth path where the received light intensity increases when the optical axis is shifted in an upper left direction, and a fifth position of a fifth path where the received light intensity increases when the optical axis is shifted in a lower left direction;
a processor; and
a memory storing instructions executable by the processor to:
determine presence or absence of an optical axis shift and calculate an amount of the optical axis shift based on a change in a received light intensity ratio between the received light intensity of the optical signal at the first position and the received light intensity at the second, third, fourth, or fifth position.