Aurélien Coillet

Phase steps and resonator detuning measurements in microresonator frequency combs

Experiments and theoretical modelling yielded significant progress toward understanding of Kerr-effect induced optical frequency comb generation in microresonators. However, the simultaneous Kerr-mediated interaction of hundreds or thousands of optical comb frequencies with the same number of resonator modes leads to complicated nonlinear dynamics that are far from fully understood. An important prerequisite for modelling the comb formation process is the knowledge of phase and amplitude of the comb modes as well as the detuning from their respective microresonator modes. Here, we present comprehensive measurements that fully characterize optical microcomb states. We introduce a way of measuring resonator dispersion and detuning of comb modes in a hot resonator while generating an optical frequency comb. The presented phase measurements show unpredicted comb states with discrete π and π/2 steps in the comb phases that are not observed in conventional optical frequency combs.

Electronic synthesis of light

We report on bidirectional frequency conversion between the microwave and optical domains using electro-optics. Advances in communications, time keeping, and quantum sensing have all come to depend upon the coherent interoperation of light wave and microwave signals. To connect these domains, which are separated by a factor of 10,000 in frequency, requires specialized technology that has until now only been achieved by ultrafast mode-locked lasers. In contrast, electro-optic modulation (EOM) combs arise deterministically by imposing microwave-rate oscillations on a continuous-wave laser. Here we demonstrate electro-optic generation of a 160xa0THz bandwidth supercontinuum and realize f-2f self-referencing. Coherence of the supercontinuum is achieved through optical filtering of electronic noise on the seed EOM comb. The mode frequencies of the supercontinuum are derived from the electronic oscillator and they achieve <5×10−14 fractional accuracy and stability, which opens a novel regime for tunable combs with wide mode spacing apart from the requirements of mode locking.

Analysis of Phase-Locking in Narrow-Band Optoelectronic Oscillators With Intermediate Frequency

In this paper, we investigate the phenomenon of phase-locking in laser-based optoelectronic oscillators from the point of view of nonlinear dynamics. We provide a theoretical and experimental analysis of the phase dynamics of these oscillators when driven by an external voltage in the intermediate frequency range. This configuration leads to phase-locking phenomena that can be theoretically analyzed from the viewpoint of Arnold tongues theory. Our research permits to determine analytically the range of parameters where the amplitude and the frequency of the driving source induce phase-locking.

A microrod-resonator Brillouin laser with 240 Hz absolute linewidth

We demonstrate an ultralow-noise microrod-resonator based laser that oscillates on the gain supplied by the stimulated Brillouin scattering optical nonlinearity. Microresonator Brillouin lasers are known to offer an outstanding frequency noise floor, which is limited by fundamental thermal fluctuations. Here, we show experimental evidence that thermal effects also dominate the close-to-carrier frequency fluctuations. The 6 mm diameter microrod resonator used in our experiments has a large optical mode area of ~100 μm2, and hence its 10 ms thermal time constant filters the close-to-carrier optical frequency noise. The result is an absolute laser linewidth of 240 Hz with a corresponding white-frequency noise floor of 0.1 Hz2 Hz−1. We explain the steady-state performance of this laser by measurements of its operation state and of its mode detuning and lineshape. Our results highlight a mechanism for noise that is common to many microresonator devices due to the inherent coupling between intracavity power and mode frequency. We demonstrate the ability to reduce this noise through a feedback loop that stabilizes the intracavity power.

Phase Noise Performance of Optoelectronic Oscillators Based on Whispering-Gallery Mode Resonators

Optoelectronic oscillators based on whispering-gallery mode resonators (WGMRs) are efficient oscillators for ultra-stable microwave generation, in which the energy can be stored in an ultra-high Q-factor resonator instead of the usual long delay line. In this paper, we derive a stochastic model for the calculation of the phase noise performance in these systems considering three different configurations, namely, the case where the energy is stored in high-Q disk-shaped WGMR, the case where energy is stored in an optical delay-line only, and the case for which the energy is stored simultaneously by the resonator and the delay line. Our investigations explain how the WGMR can be optimally used for spurious peak rejection in optoelectronic oscillators. Our experimental measurements are found to be in excellent agreement with analytical and simulation results.

Corrigendum: Phase steps and resonator detuning measurements in microresonator frequency combs

Corrigendum: Phase steps and resonator detuning measurements in microresonator frequency combs

Optical Kerr frequency combs: Modelling and applications

Whispering gallery mode resonators have generated a broad interest in recent years. From a fundamental point of view, they enable to investigate various phenomena related light-matter interactions, as well as the dynamics of photons confined in nonlinear media, from both the classical and quantum perspectives. From the applied viewpoint, WGM resonators are considered as a core photonic component in the emerging discipline of microwave photonics. They are considered as promising central elements for optical filtering, add-drop systems, miniature solid-state lasers, efficient light modulators, and so on. Both aerospace and communication engineering are expected to be the areas where the impact of WGM technology will be the strongest. We provide in this communication an overview of the field as well as of the various perspectives on the challenges that will have to be met in this new discipline.

Measuring optical phases of Kerr frequency combs

We present two methods for measuring the optical phases of the spectral lines of microresonator-based frequency combs, and use these phase sensitive measurements to study novel phase-locked comb states.

Stable Mode Locking of Micro Resonator Frequency Combs

We present recent progress in obtaining phase-stable optical frequency combs in microresonators. Measurements of the phases of individual comb modes show distinct steps of π and π/2 in different sections of the comb spectra