| 摘要 |
PURPOSE:To provide an optical star coupler in which the receiving part of each terminal can always receive an optical signal by a constant threshold value and gain. CONSTITUTION:Optical information signal as an information medium is transmitted from the transmitting part of each terminal to an optical star coupler 4, in a star-shaped transmission system constituted of the plural terminals. Those optical signals are coupled by an optical coupling part 1 in the optical coupler, and inputted to an optical fiber amplifier 2. The optical fiber amplifier 2 possesses a saturating characteristic area for an input and output signal, and the output signal level of the optical signal inputted to the optical fiber amplifier 2 is amplified to a decided value regardless of the signal level. Thus, the optical signal can be always received by the constant threshold value and gain at the receiving side by re-transmitting the output signal from an optical branching part 3 to each terminal. |
