OPTICAL SIGNAL DEMODULATION DEVICE, OPTICAL SIGNAL DEMODULATION METHOD, OPTICAL SIGNAL DEMODULATION PROGRAM, AND OPTICAL BRANCH INSERTION DEVICE

摘要

PROBLEM TO BE SOLVED: To enhance demodulation accuracy of a second signal, in an optical signal generated by superposing the second signal on a first signal by frequency modulation.SOLUTION: A wavelength variable filter 11 sweeps a transmission wavelength band on a wavelength axis by control of its center wavelength by a wavelength controller 12 to perform filtering of an optical signal. An intensity detector 13 detects an intensity of transmitted light of the wavelength variable filter 11. A power spectrum acquisition part 15 measures and acquires power spectrum of the optical signal from the intensity of the transmitted light. A peak identification part 16 identifies a peak wavelength that is a wavelength corresponding to a peak position of the power spectrum. A wavelength determination part 17 determines a demodulation target wavelength by using the peak wavelength as a reference. A demodulator 18 demodulates the second signal at a demodulation target wavelength of the optical signal.