Wavelength filter automatic tuning control scheme

摘要

PURPOSE:To eliminate the need of transmitting a discriminating signal from an optical wavelength multiplexing circuit in order to take out a detection signal by bringing an input light to frequency modulation by a first discriminating signal, and also, bringing it to amplitude modulation by a second discriminating signal. CONSTITUTION:In an optical wavelength multiplexing circuit 100, a wavelength multiplex optical signal is brought to frequency modulation by a first discriminating signal whose frequency is lower than input data which is determined in advance at every wavelength of light, and also, an input data signal is brought to amplitude modulation by a second discriminating signal. Accordingly, by taking out the second discriminating signal in an output of a wavelength filter 120, a signal whose frequency and phase are both the same as those of the first discriminating signal can be generated. In such a way, it is unnecessary to transmit the first discriminating signal which is brought to frequency modulation at every wavelength, from the wavelength multiplexing circuit 100, and the center wavelength of the wavelength filter 120 can be tuned to prescribed wavelength.