Patent ID: 7061944

Claim:
A wavelength-locked loop servo-control circuit that enables real time mutual alignment of an electromagnetic signal having a peaked spectrum function including a center wavelength and a wavelength selective means for implementing a peaked passband function including a center wavelength, in a system employing electromagnetic waves, said circuit comprising: means for applying a dither modulation signal at a dither modulation frequency to said electromagnetic signal to generate a dither modulated electromagnetic signal, and inputting said dither modulated electromagnetic signal to said wavelength selective means; means for converting a portion of said dither modulated electromagnetic signal to an electric feedback signal; means for generating an error signal comprising a vector cross product of said feedback signal and said dither modulation signal; and means for adjusting the peak spectrum function of said electromagnetic signal according to said error signal, wherein said center wavelength of said electromagnetic signal becomes aligned with said center wavelength of said wavelength selective means when a frequency characteristic of said feedback signal is two times said dither modulation frequency.