Patent ID: 7023887

Claim:
An apparatus for controlling optical wavelengths of control target lights outputted from N variable wavelength light sources, where N is an integer, the apparatus comprising: a periodic modulation signal generation unit for generating N periodic modulation signals in mutually different frequencies, according to which the control target lights are to be modulated; a wavelength scanning unit for scanning at a prescribed period the control target lights modulated at the mutually different frequencies and obtaining N optical pulses having phases respectively corresponding to the optical wavelengths of the control target lights; a control signal generation unit for generating N control signals respectively from the N periodic modulation signals and N reference signals having phases respectively corresponding to reference optical wavelengths for the N variable wavelength light sources; and a phase detection unit for detecting N phase differences between phases of respective ones of the N optical pulses and phases of respective ones of the N control signals, and controlling the N variable wavelength light sources by feeding back the N phase differences to the N variable wavelength light sources respectively such that the optical wavelengths of the control target lights are controlled by an optical frequency pulling with respect to the reference optical wavelengths according to the N phase differences respectively.