Maxime Cavillon

Brillouin Properties of a Novel Strontium Aluminosilicate Glass Optical Fiber

Presented here are the selected optical, physical, and Brillouin-related properties of a novel silica-clad, strontium aluminosilicate (SrAlSi) glass optical fiber produced using the molten core method. The Brillouin gain coefficient was found to be 0.11 × 10-11 m/W, which is about 20 × lower than conventional silica glass optical fibers. The SrAlSi core fiber also has a near-zero temperature coefficient of Brillouin frequency shift (-0.064 MHz/K) and can be considered athermal for all intents and purposes. Additional physical and Brillouin properties of the individual glass components are deduced through the use of an additive model. As a highlight, strontia (SrO) is found to have a large negative Pockels photoelastic coefficient of p12 = - 0.245. Various other bulk properties, such as the acoustic velocity, refractive index, mass density, thermo-optic, and thermo-acoustic, as well as strain-optic and strain-acoustic coefficients are provided.

Single- and few-moded lithium aluminosilicate optical fiber for athermal Brillouin strain sensing.

Results are presented toward realizing a true single-mode fiber whose Brillouin frequency shift is independent of temperature, while its dependence on strain is comparable to conventional high-silica-content single-mode fibers. Demonstrated here is a fiber with a negative thermal sensitivity dν/dT of -0.26  MHz/K and a strain sensitivity of +406  MHz/%. The suppression of the Brillouin thermal response is enabled by the large thermal expansion coefficient of the group I oxide-containing silica glass network.

Additivity of the coefficient of thermal expansion in silicate optical fibers

A model that predicts the material additivity of the thermal expansion coefficient in the binary silicate glasses most commonly used for present (GeO2-SiO2, P2O5-SiO2, B2O3-SiO2, and Al2O3-SiO2) and emerging (BaO-SiO2) optical fibers is proposed. This model is based on a derivation of the expression for the coefficient of thermal expansion in isotropic solids, and gives direct insight on the parameters that govern its additivity in silicate glasses. Furthermore, a consideration of the local structural environment of the glass system is necessary to fully describe its additivity behavior in the investigated systems. This Letter is important for better characterizing and understanding of the impact of temperature and internal stresses on the behavior of optical fibers.

On the thermo-optic coefficient of P 2 O 5 in SiO 2

Measurements of the thermo-optic coefficient (dn/dT) are made on a binary phosphosilicate core glass optical fiber. Using these results, dn/dT for the P2O5 constituent is found to be −13.3 × 10−6 ± 8.0% K−1, a value much lower in magnitude than reported in the literature for this system. Its accurate elucidation is especially useful in guiding the design of low- or negative-thermo-optic glasses and optical fibers. The phosphosilicate core also has a coefficient of thermal expansion that is higher than that of the pure silica cladding. As a result, the clad fiber geometry slightly lessens the effectiveness of the negative-valued contribution to dn/dT by P2O5 relative to bulk glass.

A unified materials approach to mitigating optical nonlinearities in fiber laser

This paper provides a road-map for the development of simple core/clad optical fibers whose enhanced performance - in particular, marked reductions in optical nonlinearities - is achieved materially and not through the more conventional present routes of geometrically complex fiber design. More specifically, the material properties that give rise to Brillouin, Raman, and Rayleigh scattering, transverse mode instabilities (TMI), and n2-mediated nonlinear effects are compiled and results on a wide range of optical fibers are discussed with a focus on trends in performance with glass composition. Further, optical power scaling estimations as well as binary and ternary property diagrams associated with Rayleigh scattering, the Brillouin gain coefficient (BGC) and the thermo-optic coefficient (dn/dT) are developed and employed to graphically represent general trends with composition along with compositional targets for a single intrinsically low nonlinearity, silica-based optical fiber that can achieve the powerscaling goals of future high energy fiber laser applications.

Materials for optical fiber lasers: A review

Over the past two decades, fiber laser technologies have matured to such an extent that they have captured a large portion of the commercial laser marketplace. Yet, there still is a seemingly unquenchable thirst for ever greater optical power to levels where certain deleterious light-matter interactions that limit continued power scaling become significant. In the past decade or so, the industry has focused mainly on waveguide engineering to overcome many of these hurdles. However, there is an emerging body of work emphasizing the enabling role of the material. In an effort to underpin these developments, this paper reviews the relevance of the material in high power fiber laser technologies. As the durable material-of-choice for the application, the discussion will mainly be limited to silicate host glasses. The discussion presented herein follows an outward path, starting with the trivalent rare earth ions and their spectroscopic properties. The ion then is placed into a host, whose impact on the spectroscopy is reviewed. Finally, adverse interactions between the laser lightwave and the host are discussed, and novel composition glass fiber design and fabrication methodologies are presented. With deference to the symbiosis required between material and waveguide engineering in active fiber development, this review will emphasize the former. Specifically, where appropriate, materials-based paths to the enhancement of laser performance will be underscored.

Low nonlinearity Yb-doped fluorosilicate optical fiber with ultra-flat absorption spectrum

We report on new Yb-doped fluorosilicate optical fibers with reduced strength of Brillouin, Raman, and thermal Rayleigh scattering. Yb3+ absorption spectra strongly resemble borate glasses, with ultra-flat absorption in the 940nm region.

Yb-Doped Fluorosilicate Optical Fiber Development For Laser Cooling and Radiation Balancing Applications

With F content greater than about 5at%, Yb doped fluorosilicate fibers exhibit the short average emission wavelengths and long lifetimes characteristic of the fluoride glasses used in cooling applications. Evidence of cooling behavior is presented.