Design of tunable optical frequency comb generation based on electro-optic modulator

An optical frequency comb having 24 channels with 1.1 dB maximum power deviation and tunable channel spacing is demonstrated by controlling the amplitude of a periodic Gaussian-shaped radiofrequency signal applied to the two cascaded intensity modulators followed by a phase modulator. The channel spacing and frequency of the comb generator can be tuned by tuning the RF signal oscillating frequency and frequency of the laser source, respectively. Furthermore, the comb spectrum flatness is achieved by controlling the pulse profile of periodic optical signal, which is controlled by the amplitude of a radiofrequency signal. The proposed optical frequency comb would be beneficial as a multichannel source in super-capacity and high-performance optical transport networks.