| 摘要 |
PURPOSE:To considerably reduce the cost of a center equipment per channel by sending a signal light and a DC light subjected to wavelength multiplexing so as to increase number of user equipments to be accommodated without increasing a signal speed. CONSTITUTION:The drive of each of high-outputs LD 11-1,11-2 is controlled by a drive control circuit 12. Furthermore, the modulation of the high output LD 11-1 is conducted in time division corresponding to each user equipment. A signal light whose wavelength is lambda1 and a DC light whose wavelength is lambda2 outputted from each of the high outputs LD 11-1,11-2 are multiplexed by a multiplexer 16, the wavelength multiplexed light is distributed into 1/n by a star coupler 13 and sent to optical transmission lines 5-1 corresponding to respective user equipment. The signal light sent from each user equipment via an optical transmission line 5-2 is detected by n-sets of photodetectors 14-1 to 14-n, from which a reception signal R is obtained. Moreover, the synthesis and the distribution of the signal light and the DC light are attained by the star coupler 13 and the loss attended with the wave multiplex is reduced by using the multiplexer 16. |
