Tunable optical frequency comb in a microresonator using amplitude and frequency modulation

Optical frequency combs are generated using cavity soliton in the microresonator comprising a vertical cavity surface emitting laser with graphene saturable absorber and coupled with frequency selective feedback. The ranges of the system parameters that support optical frequency comb have been identified. The effects of amplitude modulation and frequency modulation of the input beam on the optical frequency comb have been shown. Optical frequency comb is found to be tunable by controlling amplitude modulation and frequency modulation of the input beam as well as a few system parameters, like the line width parameters for both active and passive materials. All these theoretical results are obtained by numerically solving the governing equation, namely, a complex Ginzburg–Landau equation using the split-step Fourier method. The results can be used as a guideline for generating and tuning stable on-chip optical frequency comb.