A unified materials approach to mitigating optical nonlinearities in optical fiber. II. B. The optical fiber, material additivity and the nonlinear coefficients

Abstract

The purpose of this paper, Part IIB in the trilogy [Int J Appl Glass Sci. 2018 (not available); Int J Appl Glass Sci. 2018 (not available); Int J Appl Glass Sci. 2018(not available)], is to describe the continuum models employed to deduce the effects of differential thermal expansion in the clad optical fiber in addition to the nonlinear optical behaviors at high intensities of light. In this continuation of Part IIA, more of the state-of-the-art in W-S-based continuum material models are reviewed here with specific examples provided based on canonical material systems suggested from the findings of Part I and treated in detail in Part III. Part IIB pays particular attention to the optical fiber and its nonlinearities. K E Y W O R D Slasers, optical fibers, optical glasses, optical properties

A unified materials approach to mitigating optical nonlinearities in optical fiber. III. Canonical examples and materials road map

“…For the SAL fiber, the measured Brillouin gain data fit best when the individual La 2 O 3 and Al 2 O 3 components, along with SiO 2 , were used. Based on the known properties of fused silica, along with previously additivity‐deduced properties of the Al 2 O 3 component from measurements on aluminosilicate glasses, contributions from the La 2 O 3 components also can be deduced and are shown in Table in Companion Paper IIB . Based on the p 12 < 0 values deduced for Al 2 O 3 and La 2 O 3 , the resultant (modeled) curve exhibits the p 12 = 0 minima.…”

“…Relative Brillouin gain coefficient, BGC (in decibels, dB ), relative to conventional, telecommunications single‐mode fiber ( SMF ‐28™) as a function of non‐silica concentration (in mole percent) for a variety of molten core‐derived optical fibers. The curves are modeled results based on the additivity approaches described in Companion Papers II and the open circles, color‐coded to match the glass systems associated with the model curves, are experimental results. Data on each fiber and specific compositions of the ternaries are provided in the associated References noted…”

“…In the lanthanum aluminosilicate fiber, a homogenous SAL glass rod was first made and then employed as the core phase in a rod‐in‐tube fiber draw arrangement. In conducting the modeling, per those methods outlined in Companion Paper IIB, the measured data fit both systems best when the properties of crystalline YAG were employed in the former case and the properties of a mixture of La 2 O 3 and Al 2 O 3 were used in the latter. Since homogeneous crystalline YAG possesses a small but positive p 12 value, when mixed with the p 12 > 0 SiO 2 ( p 12 = 0.226 at a wavelength of 1550 nm for fused silica), there is no composition where the resultant “YAG‐derived” silicate glass would show a BGC log → −∞ feature.…”

“…Companion Paper I provided a fundamental description of the thermodynamical and physical origins of each effect along with the general dependencies of each on material properties and parameters. Companion Papers II discussed simple macroscopic additivity models that have proved quite useful for estimating the relevant optical, acoustic, thermal, and physical properties of multicomponent glasses. The intent of this paper is to build from the fundamentals of Companion Paper I and describe the properties of specific glass families as they relate to the aforementioned performance‐limiting optical nonlinearities.…”

A unified materials approach to mitigating optical nonlinearities in optical fiber. I. Thermodynamics of optical scattering

“…The second paper in this trilogy, provided in two parts, treats macro‐scale additivity models that have been developed to compute or predict the material properties and gain coefficients for the nonlinearities discussed herein . With these models in hand, the third paper then uses the foundations of this first paper, along with the models from the second paper(s), coupled with existing results from the literature to define a series of practical glass families for use in high power and high energy fiber optic systems …”