| 摘要 |
PURPOSE:To attain simple identification and reproduction by applying wavelength multiplex to an optical signal using codes whose code logic is inverted and outputting the result in a transmission system, taking the difference of power of optical signals of two waves after wave branching in a reception system and identifying the signal to be obtained. CONSTITUTION:Two wavelength lights outputted from laser diodes LD1, LD2 are modulated by digital signals Q, inverse of Q whose code logic is inverted by a drive circuit 1 and the result is multiplexed at a synthesizer 6 by polarized wave controllers 2, 3 and variable attenuators 4,5. The light of two wavelengths passes through a same bus in an optical talking device comprising an optical transmission line 7 and an optical switch network 8 and is subjected to same fluctuation. A differential signal D and its inversional signal D are obtained from the signal of two wavelengths branched at a branching device 9 on a reception side. The signals are received by a differential input light receiving device 10, the signals D and the inverse of D are obtained from the difference at an identification device 11. Thus, the fluctuation of an OFF level is canceled and the reference level of the identification is made constant, then the signal is identified. |
