| 摘要 |
PURPOSE:To reduce the effect of crosstalk due to an optical signal other than a wavelength to be selected by converting an optical amplitude modulation signal into an electric signal and then converting the electric signal into an optical frequency modulation signal whose center wavelength is the same as or different from that of the optical= frequency modulation signal so as to apply exchange connection. CONSTITUTION:FSK wave converters 150, 151, and 152 convert ASK signals 20, 21 and 22 into FSK signals 30, 31 and 32 whose center wavelength is respectively lambda1, lambda2, lambda3 and send the result to a multiplexer 121. Multiplexed optical signals being the FSK signals 30, 31 and 32 from the multiplexer 121 are branched into fixed wavelength selection elements 160, 161 and 162 via a demultiplexer 131. The fixed wavelength selection elements 160, 161 and 162 select fixedly a light with a wavelength corresponding to 1 level of the FSK signals 30, 31 and 32 whose center wavelengths are respectively lambda1, lambda2, lambda3 or a wavelength corresponding to a 0 level from the multiplexed light of the FSK signals 30, 31 and 32 from the demultiplexer 131 and send the selected light to photoelectric converters 170, 171 and 172. |
