Conference Agenda

Brillouin scattering has found extensive applications in advanced photonics functions, including microwave photonics, signal processing, sensing, and lasing. More recently, it has been employed in micro- and nano-photonic waveguides. Tapered optical fibers, due to their small transverse dimensions, exhibit a range of optical and mechanical properties that render them highly attractive for both fundamental physics research and technological applications. By employing a heat brushing technique, we can create suspended subwavelength silica rods over several centimeters with minimal loss. In contrast to standard telecom fibers, where Brillouin scattering is characterized by a single Lorentzian resonance centered at 10.86 GHz (@ 1550 nm), tapered silica fibers exhibit multiple Brillouin resonances at various frequencies ranging from 5 GHz to 10 GHz, originating from surface, shear, and compression elastic waves. Surface acoustic waves are sensitive to their environment, while compression waves efficiently convert light. Recently, we demonstrate that a large evanescent optical field surrounding the nanofiber, exibit an efficient Brillouin scattering in gas. We show drastic Brillouin scattering enhancement by increasing the gas pressure (CO2, 47 Bar) with a maximum Brillouin gain which is 79 times larger than in a SMF.

In this paper, we have presented a novel and compact bicolor Bessel beams (bi-BBs) generator based on a single-mode fiber integrated with an axicon-like microstructure (AM). The proposed design utilized two Bessel beams manifested as pump beam of circular distribution at λ=405 nm and STED beam of donut distribution at λ=532 nm. Through numerical simulations, a type of AMs has been found to support STED system light source. The influence of the AM size variance on the characteristics of bi-BBs was also investigated. With optimized AM, the bi-BBs emitted from a single-mode fiber greatly reduces the coaxial alignment difficulty of the free space STED systems and may also provide a new way to achieve mirrorless STED super-resolution systems.

We present the design of composite optical nanofibers coated with different nonlinear materials (PMMA and TiO2) for the realization of new all-solid Raman wavelength converters. Two coating processes, multilayer dip-coating and atomic layer deposition, have been successfully developed and optimized for the functionalization, inducing only relatively low losses comprised between 0.5 dB and 1.76 dB on 2 cm. Encapsulation has also been demonstrated. The Raman modal gain coefficients have been calculated to lie between 0.3 and 0.4 m-1W-1. Based on our previous results obtained with nanofibers immersed in different liquids, Raman threshold in the ns second regime should be obtained with few cm long nanofibers. This work opens the way to a new family of composite nanofibers for different applications in nonlinear optics.

We explore fiber Fabry-Pérot (FFP) resonators, a new platform for frequency comb generation We experimentally identified mirror diffraction losses dependent on the effective area of the fiber and simulated them via Fourier optics. In the nonlinear regime, a linear stability analysis of a generalized Lugiato-Lefever equation revealed optimization of reflectivity and detuning, leading to a significant reduction in the required power threshold for comb generation compared to linear regime, and to improved energy frugality. Furthermore, controlled or exploited birefringence in various experimental settings enabled the generation of Kerr frequency combs and stimulated Brillouin lasers. In this communication we propose an overview of the practical characteristics related to the fabrication and use of these resonators.

An innovative integration method was recently proposed to integrate miniaturized optical sources on the facet of an optical fiber in a monolithic fashion. Recent advancements concerning the coupling efficiency improvement will be presented.