| 摘要 |
PURPOSE:To reduce the system cost and to improve the multiplexity by applying FM modulation to a signal in the stage of an electric signal to differentiate the band of each frequency-modulated signal, applying electrooptic conversion to the FM modulation signal and making the wavelength of each optical signal identical. CONSTITUTION:After a communication electric signal is modulated so that the frequency band of modulated signals is differentiated from each other in each of multi-points (201-20N), electrooptic conversion is applied to optical signals of the save wavelength and the resulting signal is sent to an optical transmission line 25. Then an electric signal obtained through optoelectric conversion at a center 26 is subject to band-split into each modulated signal and each modulated signal is demodulated to obtain a communication electric signal at the multi- points (201-20N). Thus, optical signals outputted from the multi-points (201-20N) have the same wavelength. Thus, the system cost is reduced to a low cost and the multiplexity is improved. |
