Optical tank circuits used for all-optical timing recovery

A novel all-optical timing-recovery scheme that uses an optical tank circuit is presented. An optical clock synchronized to an incoming data stream is generated by extracting line spectral components in the incoming data stream using an optical resonator whose free spectral range is equal to the incoming data bit rate. The principle of operation is demonstrated using a confocal Fabry-Perot-type optical tank circuit and a fiber-ring-type optical tank circuit at 2 Gb/s and 324 Mb/s, respectively. Quality factor in the baseband domain is measured and shown to agree well with the theoretical value. A workable data bit rate, required source linewidth, and stability are discussed