| 摘要 |
PURPOSE:To attain low cost and to improve reliability by applying Brillouin amplification so as to select a channel and using a return signal so as to modulate and send back excited light used for the Brillouin amplification thereby constituting a simple subscriber terminal equipment. CONSTITUTION:A signal light subject to frequency multiplex by an optical multiplexer 2 is made incident in an optical fiber 3 through an optical demultiplexer 51. On the other hand, the excited light projected from a semiconductor laser 61 is modulated by a return signal fed to an electric signal input terminal 62 of an intensity modulator 63 and coupled with an optical fiber 3 by an optical demultiplexer 72. The oscillated frequency of the semiconductor laser 61 is set higher than the frequency of a prescribed channel by the Brillouin shift by a control section 81. Then a photoreception section 71 reads the return signal by using the excited light, that is, the return signal light. Thus, no optical demultiplexer for frequency multiplex light is required at the subscriber terminal equipment and one light source is enough for the system, then the network with low cost and high reliability can be constituted. |
