| 摘要 |
PROBLEM TO BE SOLVED: To increase the number of nodes which can be connected to a network and to suppress deterioration of receiving characteristics due to crosstalk light by allowing a part of plural communication nodes to transmit an optical signal subjected to phase-modulation in addition intensity-modulation in a transmission part. SOLUTION: In a node 110a receiving an optical signal from the output terminal 108a of an optical router 101, e.g. the optical signal is demultiplexed into wavelengths λ1 to λ4 by a demultiplexer 114. A demodulation part 115 optical-to-electrical transducing the demultiplexed optical signal demodulates the optical signal to an electric signal to remove unnecessary noise component from the electric signal by a base band filter. The demodulated and noise- removed electric signal is inputted to a signal processing part 111 and given processing of transmitted information, etc. The modulation part 112 of nodes 110a, 110b connected to every other respective terminals of the router 101 transmits the optical signal by intensity modulation. Further, the modulation part 122 of nodes 120a, 120b connected to every other respective terminals of the router 101 transmits the optical signal by phase modulation in addition to intensity modulation. |
