Orthogonally Polarized Kerr Frequency Combs
Abstract
Kerr optical frequency combs with multi-gigahertz spacing have previously been demonstrated in chip-scale microresonators, with potential applications in coherent communication, spectroscopy, arbitrary waveform generation, and radio frequency photonic oscillators. In general, the harmonics of a frequency comb are identically polarized in a single microresonator. In this work, we report that one comb in one polarization is generated by an orthogonally polarized soliton comb and two low-noise, orthogonally polarized combs interact with each other and exist simultaneously in a single microresonator. The second comb generation is attributed to the strong cross-phase modulation with the orthogonally polarized soliton comb and the high peak power of the intracavity soliton pulse. Experimental results show that a second frequency comb is excited even when a continuous wave light as a "seed"-with power as low as 0.1 mW-is input, while its own power level is below the threshold of comb generation. Moreover, the second comb has a concave envelope, which is different from the sech2 envelope of the soliton comb. This is due to the frequency mismatch between the harmonics and the resonant frequency. We also find that the repetition rates of these two combs coincide, although two orthogonal resonant modes are characterized by different free spectral ranges.
Cite
@article{arxiv.1705.05045,
title = {Orthogonally Polarized Kerr Frequency Combs},
author = {Changjing Bao and Peicheng Liao and Arne Kordts and Lin Zhang and Andrey Matsko and Maxim Karpov and Martin H. P. Pfeiffer and Guodong Xie and Yinwen Cao and Yan Yan and Ahmed Almaiman and Zhe Zhao and Amirhossein Mohajerin-Ariaei and Ahmad Fallahpour and Fatemeh Alishahi and Moshe Tur and Lute Maleki and Tobias J. Kippenberg and Alan E. Willner},
journal= {arXiv preprint arXiv:1705.05045},
year = {2017}
}