In this communication, present some of our latest results related to Kerr optical frequency comb generation. We investigate the conditions under which the energy conversion from the lightwave to the microwave spectral ranges is optimized. Our main finding is that the optimal regime features a pump-to-sidemode ratio smaller than 4 dB, corresponding to a conversion efficiency better than 40 %.
Whispering gallery mode resonators have been the focus of many research works in recent years. They allow to study the light-matter interactions induced by the confinement of photons in nonlinear media. In particular, Brillouin Raman and Kerr nonlinearities excite the resonator at the lattice, molecular and electronic scale. This difference in spatial scales give to whispering gallery-mode resonators the potential to be central photonic components in microwave photonics, quantum optics and optoelectronics. We discuss in this communication some of the key challenges that have to be met for the understanding of Kerr, Raman and Brillouin interactions that can take place in these resonators.
We report an investigation on optoelectronic oscillators based on a combination of a fiber delay line and a whispering gallery mode resonator. We analyze the dynamical processes which are key for the understanding of the spectral purity of these oscillators. We therefore show how combining both optical elements leads to significant improvement of the spectral purity of the oscillator, as it leads to a spurious rejection rate higher than 50 dB.
We report and discuss some of the latest advances in Kerr optical frequency comb generation. We principally focus on widely tunable primary combs, and on the role played by the eigenmode family of the modes of interest. Our work shows that there is a giant dispersion shift between the various radial families of modes, and that we can use them to generate primary combs with significantly different intermodal spacings.
We theoretically and experimentally investigate some effects related to the Kerr optical frequency comb generation, using a millimeter-size magnesium fluoride ultrahigh quality disk resonator. We show that the Kerr comb tunability can be extremely wide in the Turing pattern (or primary comb) regime, with an intermodal frequency that can be tuned from 4 to 229 multiple free spectral ranges (corresponding to a frequency spacing ranging from 24 GHz to 1.35 THz). We also discuss the role played by thermal locking while pumping the resonator, as well as the effect of modal crossing when broadband combs are generated.