| 摘要 |
PURPOSE:To suspend power supply to part of a reception system circuit includ ing a light receiving element circuit without impairing a start-up control in a waiting state. CONSTITUTION:This device is provided with a light emitting element circuit 4 which generates a burst transmission optical signal 3 from a transmission signal 5, a light receiving element circuit 10 which generates a reception signal 11 from a burst reception optical signal 9, and an optical directivity coupler 2 which supplies the transmission optical signal 3 to an optical cable 1 being a subscriber's line transmission path, and supplies the reception optical signal 9 from the optical cable 1 to the light receiving element circuit 10. In the case of the absence of the detection of a reception signal 221 by a photodetecting circuit 22, that is, in the waiting state of a communication, a power source control circuit 30 attains the power-down of the light emitting element circuit 10 and an amplifier 12 in a cycle different from the burst cycle of the reception optical signal 9 under the control of a reception control circuit 19. |
