Generation of stable and high-quality frequency-locked carriers based on improved re-circulating frequency shifter

An optical multicarrier generator based on the improved re-circulating frequency shifter (RFS) to generate a larger number of frequency-locked carriers with high-quality has been studied. By eliminating the third-order crosstalk components, the output carrier's number and optical signal-to-noise-ratio (OSNR) of the generator have been improved significantly. In addition, the maximum output OSNR and optimal radio-frequency drive voltages in the cases of different desired carrier numbers have been obtained. Using the improved configuration, 130-tone with high-quality (tone-to-noise ratio ∼20 dB and superior flatness <3 dB) where the drive voltage is only around 0.5Vπ can be achieved. The simulation results show a good agreement with the theoretical analysis. The multicarrier generator based on the improved RFS has the potential application in the terabit superchannel optical transmission.