Patent ID: 8494318
Filing Date: 2013-07-23
Classification: G02B,H04J

Abstract:
1. A method for filtering an optical signal comprising a plurality of channels lying on a grid of optical frequencies equally spaced by a frequency spacing and occupying an optical bandwidth, the method comprising: operating an optical filter comprising resonators, each resonator having a respective free spectral range, wherein a first resonator is optically coupled to the optical signal and the remaining one or more resonators are optically coupled in series to the first resonator, so that a respective resonance of each one of the resonators falls within a first frequency band having bandwidth less than or equal to 15 GHz; first tuning at least one resonator with respect to at least another resonator to obtain a separation between any resonance of at least one resonator falling within the optical bandwidth with respect to a resonance of at least another resonator nearest to the any resonance, the separation being greater than or equal to 150 GHz and no more than 1 THz; second tuning all the resonators of the optical filter so as to move all respective resonances of the resonators by a respective frequency interval greater than the frequency spacing while maintaining a distance between the any resonance of the at least one resonator with respect to the nearest resonance of the at least another resonator not less than 150 GHz and no more than 1 THz; and third tuning the at least one resonator and the at least another resonator such that a further respective resonance of each one of the resonators falls within a second frequency band, different from the first frequency band, having bandwidth less than or equal to 15 GHz.