Coherent comb generation with continuous sweep of repetition rate over one-octave

We proposed and demonstrated a coherent optical frequency comb generation with broadband continuous sweep of repetition rate based on cascaded phase and intensity modulators. Broadband phase matching between electrical drive signals applied on the cascaded phase and intensity modulators is achieved by compensating propagation delay skew between optical signal path and electrical signal path. Therefore, phase mismatch induced flatness deterioration is effectively suppressed. A flat-top 19-line optical frequency comb with repetition rate continuously sweeping over one-octave from 8.5 to 19 GHz is obtained, where the overall power deviation is.