Step-index profile

About: Step-index profile is a research topic. Over the lifetime, 3104 publications have been published within this topic receiving 53199 citations.

Mach-Zehnder interferometric devices with composite fibers

Abstract: A Mach-Zehnder wavelength selective device is made using one or more composite optical fibers each incorporating a phase shift region having one effective refractive index spliced between coupling regions having a different effective refractive index. The optical path length difference or phase delay induced by each such composite fiber is a linear function of the length of the phase shift region.

Liquid Refractive Index Sensor Based on a Polarization-Maintaining Fiber Loop Mirror

Abstract: A liquid refractive index sensor based on a fiber loop mirror (FLM) combined with an etched polarization maintaining fiber (PMF) is proposed. As the etched section of the PMF is immersed in liquid with different refractive indices, the interference spectrum of the FLM presents high sensitivity to the surrounding-medium refractive index. High sensitivity of 25.29 nm/refractive index unit (RIU) and resolution of $7.91\times 10^{-4}$ RIU are achieved for the proposed refractive index sensor. This sensor is also capable of simultaneous measurement of refractive index and temperature.

Thermally induced optical effects in double-coated optical fibers by viscoelastic theory

Abstract: A viscoelastic theory is adopted to analyze the optical effects in double-coated polymeric optical fibers subjected to thermal loadings. A closed-form solution of the microbending loss and refractive index changes obtained by using the Laplace transformation method is presented. To obtain the solution, the compatibility conditions of displacement at interfaces and Lame's formula for the stress components are used. The results are initially identical to those obtained by the elastic analysis, and then decrease gradually as time progresses. To minimize the microbending loss, the polymeric coatings were suitably selected, so that the Young's moduli, Poisson's ratios, and viscosities of the primary and secondary coatings would decrease. Furthermore, selecting suitable primary and secondary coatings with lower Young's moduli, Poisson's ratios, and viscosities reduce the changes of refractive index in the glass fiber.

Theoretical and empirical comparison of coupling coefficient and refractive index estimation for coupled waveguide fiber

Abstract: Power transmission and coupling of coupled waveguide fibers are affected on the coupling coefficient. The coupling coefficients obtained in experimental results vary in widely. The coupling coefficients have a function of separation of fiber axis and refractive index of core and cladding. For the empirical formula, coupling coefficient is calculated from experimental result of coupling ratio distribution from 1% until 75%. Theoretically, the coupling coefficient has a dependence of some parameters resulting in a sinusoidal curve. Both empirical and theoretical formulae are compared to obtain new phenomena of the refractive index of fibers after fusion.