Numerical simulation of mid-infrared optical frequency comb generation in chalcogenide As2S3 microbubble resonators

Abstract

Mid-infrared optical frequency comb generation in whispering gallery mode microresonators attracts significant interest. Chalcogenide glass microresonators are good candidates for operating in the mid-infrared range. We present the first theoretical analysis of optical frequency comb generation in As2S3 microbubble resonators in the 3-4 μm range. The regime of dissipative soliton plus dispersive wave generation is simulated numerically in the frame of the Lugiato-Lefever equation. Using microbubble geometry allows controlling of the zero-dispersion wavelength and the obtaining of anomalous dispersion needed for soliton generation at the pump wavelength of 3.5 μm, whereas the zero-dispersion wavelength of the analyzed As2S3 glass is ~4.8 μm. It is shown that, for the optimized characteristics of microbubble resonators, optical frequency combs with a spectral width of more than 700 nm (at the level of -30 dB) can be obtained with the low pump power of 10 mW.