Nonlinear optical effects are by default weak but they can be enhanced by sculpting the resulting spectrally periodic pulses from a fibre laser into an optimal shape.
A monolithic chip-scale ring laser gyroscope based on both Brillouin and Sagnac effects provides a sensitivity sufficient to measure sinusoidal rotations with an amplitude as small as 5 degrees per ...hour, thus enabling the first on-chip Earth rotation measurement.
Abstract
Understanding dynamical complexity is one of the most important challenges in science. Significant progress has recently been made in optics through the study of dissipative soliton laser ...systems, where dynamics are governed by a complex balance between nonlinearity, dispersion, and energy exchange. A particularly complex regime of such systems is associated with noise-like pulse multiscale instabilities, where sub-picosecond pulses with random characteristics evolve chaotically underneath a much longer envelope. However, although observed for decades in experiments, the physics of this regime remains poorly understood, especially for highly-nonlinear cavities generating broadband spectra. Here, we address this question directly with a combined numerical and experimental study that reveals the physical origin of instability as nonlinear soliton dynamics and supercontinuum turbulence. Real-time characterisation reveals intracavity extreme events satisfying statistical rogue wave criteria, and both real-time and time-averaged measurements are in quantitative agreement with modelling.
Modulation instability is a fundamental process of nonlinear science, leading to the unstable breakup of a constant amplitude solution of a physical system. There has been particular interest in ...studying modulation instability in the cubic nonlinear Schrödinger equation, a generic model for a host of nonlinear systems including superfluids, fibre optics, plasmas and Bose-Einstein condensates. Modulation instability is also a significant area of study in the context of understanding the emergence of high amplitude events that satisfy rogue wave statistical criteria. Here, exploiting advances in ultrafast optical metrology, we perform real-time measurements in an optical fibre system of the unstable breakup of a continuous wave field, simultaneously characterizing emergent modulation instability breather pulses and their associated statistics. Our results allow quantitative comparison between experiment, modelling and theory, and are expected to open new perspectives on studies of instability dynamics in physics.
In this study, we report the generation of multi-wavelength light sources through enhanced four-wave-mixing processes using a straightforward and adaptable dual-frequency Brillouin fiber laser. This ...passive optical and nonreciprocal cavity is first tested and analyzed with long fiber lengths up to 1 km in the 1.55 μm telecommunication C band and then in the 2-μm waveband. In the latter case, we demonstrate that our fiber cavity enables efficient multiple four-wave mixings, in the continuous-wave regime, which are commonly inaccessible in long silica-fibers due to increased losses. We also report on the tunable repetition rate from tens of GHz to hundreds of GHz, by simply changing the frequency spacing between the two continuous-wave pumps. The coherence limitations of our all-fiber system are discussed, along with the impact of the dispersion regime of the nonlinear fiber that forms the cavity.
We demonstrate an athermal Brillouin strain sensor using heavily GeO2-doped optical fibers. We also report nonlinear evolution of Brillouin temperature sensitivity as a function of wavelength and ...strong Brillouin gain in these fibers.
Spin-orbit interactions (SOI), describing the transfer of a spin degree of freedom to an orbital angular momentum (OAM), have been widely explored in recent opto-acoustic studies for applications ...mainly in spintronics and for topological insulators 1. We report the observation of SOI by Brillouin scattering in an optical nanofiber. Specifically, we describe the transfer of a spin degree of freedom from light incident to the nanofiber to an acoustic vortex with a topological charge of order 2 in the form of OAM. Coupled with the phase matching condition for the energy conservation during Brillouin scattering, it results in a backscattered wave with a spin opposite to the incident wave. This observation allows considering applications of opto-acoustic Brillouin memory based on polarization conversion through a SOI 2.
The science of the interaction of sound and light, including acousto-optics and opto-acoustics, has recently witnessed the emergence of new topics and directions that lead to a renewed understanding ...of fundamental effects and to novel applications ...
Optical nanofibers (ONFs) represent versatile nanophotonic platforms for important photonic applications such as optical sensing and quantum and nonlinear optics. The attractiveness of ONFs arises ...from the tight optical confinement, their wide evanescent field in the subwavelength limit, their surface acoustic properties, and their high tensile strength. Here we investigate Brillouin light scattering in silica-glass ONFs under high tensile strain and show that the fundamental properties of elastic waves dramatically change due to elastic anisotropy and nonlinear elasticity for strain larger than 2%. This yields to unexpected Brillouin strain coefficients for all Brillouin resonances including surface and hybrid waves, followed by a nonlinear evolution at high tensile strength. We further provide a complete theoretical analysis based on third-order nonlinear elasticity of silica that agrees well with our experimental data. These new regimes open the way to the development of compact tensile strain optical sensors based on nanofibers.
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