| 摘要 |
PURPOSE:To make it possible to measure the photo input power and output power of a photo repeater at a remote terminal station, by such simple constitution that the output lights of upward bound and downward bound repeaters are respectively inputted to the up and down repeaters through a photo feedback circuit and the input power informations thereof are transmitted to the terminal station. CONSTITUTION:In measuring photo input power, an optical switch 8 connects a laser diode 7 and an optical fiber 9 by the remote control signal transmitted from a terminal station through an optical fiber 11. In this state, a modulation circuit 6 is turned ON by the remote control signal from the terminal station and the input light inputted from the optical fiber 11 is converted to an electric signal by an avalanche photodiode 1 while said electric signal is modulated in the modulation circuit 6 by the code converted bias voltage of the avalanche photodiode 1. The modulated electric signal is received at a terminal station through optical fibers 9, 10' while converted to a laser signal by a laser diode 7. In measuring photo output power, the modulation circuit 6 is turned OFF and a modulation circuit 6' is turned ON. |
