PURPOSE: To embody a demultiplexing characteristic controller of an array waveguide diffraction grating type optical demultiplexer which is usable in actual use environment and is capable of meeting the deterioration of demultiplexing characteristics with lapse of time.
CONSTITUTION: This demultiplexing characteristic controller is composed of a light source 2, a reference signal generating means 3 which generates the reference signal indicating the result of demultiplexing in accordance with the input wavelength of the array waveguide diffraction grating type optical demultiplexer 1, an error signal generating means 4 which generates an error signal by comparing the reference signal and the demultiplexer output, an orthogonal signal generating means 6 which generates a prescribed orthogonal signal, a time correlation means 5 which obtains the time correlation of the error signal and the orthogonal signal, an integrating means 7 which accumulates the output of the time correlation means 5 and an optical path length control means 8 which independently controls the respective optical path lengths of plural channel waveguides by the signal formed by superposing the orthogonal signal on the output of the integrating means 7.
ITO FUMIHIKO
IWASHITA KATSU
