Patent ID: 9628190
Date: 2017-04-18
CPC Classifications: G02B,H04B

Claim:
1. An optical transmitter comprising: at least two light-emitting elements that emits beams; a branching device comprising input ports on which beams emitted by the light-emitting elements are incident and output ports for branching beams, incident on the input ports, into at least two beams and for emitting the beams; optical modulators that individually modulates beams emitted from the output ports, wherein the number of the light-emitting elements is N (N is a natural number of 2 or more); the branching device comprises an N×M branching device for individually branching beams incident from some of the N light-emitting elements to some of N input ports and for emitting the beams in parallel from M (M is a natural number of 2 or more) output ports; and the number of the optical modulators is M, and the optical modulators individually modulate beams individually incident from the M output ports; a monitoring unit for individually monitoring presence or absence of malfunction of the N light-emitting elements; and a control unit that: normally drives some of the N light-emitting elements in the driving unit and normally stops the remaining light-emitting elements as backups; stops driving of the light-emitting elements, which are normally driven by the driving unit and of which decrease of the outputs is detected by the monitoring unit; and starts driving of at least some of the light-emitting elements stopped due to the decrease of the outputs and of the stopped light-emitting elements, as backups, sharing the output ports of the N×M branching device.