| 摘要 |
PURPOSE:To transmit/receive up and down signals between a terminal and a start coupler through only one fiber by once converting an up optical signal into an electrical signal, amplifying the electrical signal and sending the amplified signal to the down direction through a light emitting element having different wavelength. CONSTITUTION:An output signal from a certain terminal equipment is converted into an optical signal with wavelength lambda1 by an optical transmitter and reached to the active start coupler 1. In the coupler 1, light with wavelength lambda1 made incident from an optical fiber 5 into a mixing rod 2 is passed through an optical fiber 3, converted into an electrical signal by a photodetecting element 4, amplified by an amplifier circuit 6, and converted into an optical signal with wavelength lambda2 by a light emitting element 7 and the optical signal is led into the rod 2 through an optical fiber 8. The optical signal with the wavelengthlambda2 is averaged by the rod 2, reflected by the filter 3 and reached to a multiplexer/ demultiplexer through the fiber 5. The multiplexer/demultiplexer supplied only the signal with wavelength lambda2 to an optical receiver. The output of the optical receiver is supplied to the terminal equipment as an input signal. |
