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.
Crystalline whispering-gallery-mode disk resonators are finding an increasing number of applications in photonics. Their exceptional energy storage capacity is of great interest in the area of ultrastable oscillators for aerospace and communication engineerings as well as for sensing applications. Here, we investigate the physical properties of some unconventional crystalline materials. We show that these resonators can display quality factors higher than ten million at 1550 nm and we discuss their potential for various applications.
We investigate the phase noise performance of an optoelectronic oscillator based on a calcium fluoride high quality
factor whispering gallery mode optical resonator (WGMR). In the oscillator setup, a particular attention is given to the
stabilization of the laser lightwave onto an optical resonance of the WGMR. Once the laser is stabilized, different
resonant optical modes are characterized in the microwave domain. Afterwards, phase noise spectra of different
oscillations at different modes of the WGMR are measured. Phase noise levels below -93 dBc/Hz and around
-90 dBc/Hz at 10 kHz offset frequency from 6.35 GHz and 12.7 GHz carriers are respectively obtained.
The theoretical understanding of Kerr combs has been the object of extensive efforts worldwide in the last ten years. Several insights have been provided since then into this problem and have enabled significant progress for the optimization and tailoring of these combs. Here, we investigate the formation of dissipative structures in crystalline whispering-gallery mode disk resonators that are pumped in different dispersion regimes. In the Fourier domain, these dissipative structures correspond to specific types of mode-locked Kerr optical frequency combs. Depending on the sign of the second-order chromatic dispersion and on the pumping conditions, we show that either bright or dark cavity solitons can emerge, and we show these two regimes are associated with characteristic spectral signatures that can be discriminated experimentally. We use the Lugiato-Lefever spatiotemporal formalism to investigate the temporal dynamics leading to the formation of these azimuthal solitons, as well as the emergence of Turing patterns. The theoretical results are in excellent agreement with experimental measurements that are obtained using calcium and magnesium fluoride disk resonators pumped near 1550 nm.
In this work, we present experimental results on an optoelectronic resonator (OEO) based on intensity modulation and a high-Q disk resonator. In our configuration, the crystalline whispering-gallery-mode resonator acts both as a frequency filter, selecting the microwave oscillating frequency, and as an optical storage element. In such a system, the oscillating frequency corresponds to the free spectral range of the resonator (between 10 GHz and 11 GHz), and therefore no delayinduced spurious peaks are present in the spectrum, in contrast to the case of the classical optoelectronic oscillator where the storage element consists of an optical fiber delay line. An other advantage of our system resides in its compactness allowing for efficient control of the temperature.
Based on a modal description of the evolution of the mode's amplitude in a whispering-gallery mode resonator, we numerically study the generation of Kerr combs. We show that a stable primary comb appear for pump power slightly above threshold, enabling potential applications in metrology. For high input power however, chaotic signals are observed.
Based on a modal description of the evolution Kerr combs in a whispering-gallery mode resonator, we numerically investigate the phase bhavior of the different spectral lines of the spectrum. We show that a stable phase relation exists between adjacent modes in primary combs. This result is of great interest for metrological applications where one phase noise is an issue. For high input power however, chaotic signals are observed.