Photonics Research, 2018, 6 (4): 04000238, Published Online: Mar. 22, 2019
Influences of multiphoton absorption and free-carrier effects on frequency-comb generation in normal dispersion silicon microresonators Download: 677次
Nonlinear optics, four-wave mixing Nonlinear optics, integrated optics Parametric oscillators and amplifiers Microcavities
Abstract
We investigate frequency-comb generation in normal dispersion silicon microresonators from the near-infrared to mid-infrared wavelength range in the presence of multiphoton absorption and free-carrier effects. It is found that parametric oscillation is inhibited in the telecom wavelength range resulting from strong two-photon absorption. On the contrary, beyond the wavelength of 2200 nm, where three- and four-photon absorption are less detrimental, a comb can be generated with moderate pump power, or free-carriers are swept out by a positive-intrinsic-negative structure. In the temporal domain, the generated combs correspond to flat-top pulses, and the pulse duration can be easily controlled by varying the laser detuning. The reported comb generation process shows a high conversion efficiency compared with anomalous dispersion regime, which can guide and promote comb formation in materials with normal dispersion. As the comb spectra cover the mid-infrared wavelength range, they can find applications in comb-based radiofrequency photonic filters and mid-infrared spectroscopy.
Mulong Liu, Leiran Wang, Qibing Sun, Siqi Li, Zhiqiang Ge, Zhizhou Lu, Weiqiang Wang, Guoxi Wang, Wenfu Zhang, Xiaohong Hu, Wei Zhao. Influences of multiphoton absorption and free-carrier effects on frequency-comb generation in normal dispersion silicon microresonators[J]. Photonics Research, 2018, 6(4): 04000238.