Improved Multicarriers Generation by Using Multifrequency Shifting Recirculating Loop

We propose and experimentally demonstrate a novel scheme to generate optical frequency-locked multicarriers, by using recirculating frequency shifter loop based on multifrequency shifting single-sideband (MFS-SSB) modulation with improved tone to noise ratio (TNR) performance. By using MFS-SSB modulation, we can generate N subcarriers during each round trip without interference, and the recirculation times are reduced to 1/N of the regular scheme based on single-frequency shifting SSB modulation (SFS-SSB). Finally, the double-frequency shifting SSB modulation is carried out for demonstration in our experiment with a double-carriers source. Using this scheme, we successfully generate 95 frequency-locked subcarriers with 15 GHz frequency spacing covering from 1553.81 to 1565.26 nm with TNR larger than 23.3 dB. Compared with the results of the regular SFS-SSB scheme, more subcarriers with improved TNR (8 dB for the 95th subcarrier) are obtained.