CW frequency comb generated by four-wave mixing and cascaded FWM

In order to solve the problem of generating optical frequency comb by mode-locked laser seed source, a new method to generate optical frequency comb by continuous light source was presented and the problem of phase mismatch in four-wave mixing and cascaded four-wave mixing with wide spectral range was solved by using dispersion-flattened highly nonlinear optical fiber. We experimentally demonstrated efficient generation of an equalized optical comb with nearly 40 nm bandwidth. The comb was generated by low-power, low-cost, continuous-wave seeds(FP-LDs) without needing for pulsed laser sources. The CW frequency comb were generated by four-wave mixing(FWM) and cascaded FWM whose bandwidth of the spectrum was expanded by nearly 10 times and the linewidth of the frequency comb was 4.3 MHz with 420 m zero-slope dispersion dispersion-flattened HNLF.