OPTICAL TRANSMISSION SYSTEM AND OPTICAL RECEIVER FOR THE SAME

PROBLEM TO BE SOLVED: To provide an optical transmission system capable of preventing a level of a reproducing signal from exceeding a specified value thereby improving convenience from the standpoint of operation, and to provide an optical receiver for the system. SOLUTION: In the optical transmission system wherein an optical signal analog-modulated by a signal resulting from composing a pilot signal 23 with a main signal 1 with a wireless frequency band used for the wireless interval communication of a mobile communication system is transmitted via an optical fiber 3, an optical receiver OR 1 is provided with an optical level monitor 7. Further, a variable attenuator 5 for controlling the gain of the wireless frequency signal reproduced in the optical receiver OR 1 is provided to a pre-stage of an output terminal 7. Then the level of a main signal 6 is stabilized on the basis of a level of the pilot signal 23 included in a received signal is stabilized and when a light receiving level of the optical signal monitored by an optical level monitor 7 reaches a threshold or below, the attenuation of the variable attenuator 5 is forcibly maximized. COPYRIGHT: (C)2006,JPO&NCIPI