| 摘要 |
PURPOSE:To improve economy and reliability by branching a light signal to be modulated into two, and outputting demodulating information from one and modulating nearly and returning the other. CONSTITUTION:The light signal to be modulated which is sent from an opponent station A is received and demultiplexed into two by an optical demultiplexer 4; and demodulating information is obtained from one demultiplexing output 3b, and the other 3c is modulated nearly by an optical modulator 8 and returned through an optical fiber 3d to transmit the light signal in two ways by using only one light source. Therefore, only one light emitting diode or laser diode is required as the light source in the whole system. |
