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.

Optical filter and optical apparatus

Abstract: Regarding an optical filter comprising a light-transmitting substrate, a gradient refractive index thin film with a refractive index change in the film thickness direction formed on the substrate and an anti-reflection structure formed on the gradient refractive index thin film, the gradient refractive index thin film is formed so as to have light absorbing characteristic and a refractive index characteristic such that the refractive index change comprising plural changing points with increases and decreases of the refractive index has a tendency to reduce from the side of the substrate toward the side of the anti-reflection structure. The optical filter has excellent environmental resistance and low reflection. The optical filter can be suitably used in an imaging optical system of an optical apparatus or a display of an electronic device.

Full-vectorial analysis of complex refractive index photonic crystal fibers

Abstract: We investigated the modal properties of complex refractive-index core photonic crystal fibers (PCFs) with the supercell model. The validity of the approach is shown when we compare our results with those reported earlier on a step complex refractive-index profile. The imaginary part of the electric field results in wave-front distortion in the complex refractive-index profile PCFs, which means that the power flows out or into the doped region according to the sign of the imaginary part of the refractive index. A simple formula is proposed for calculating the gain or loss coefficients of these fibers. The numerical results obtained by the approximation formula agree well with the full-vectorial results.

Oxide Glass Hollow Fiber For CO 2 Laser Radiation Transmission

Abstract: The feasibility study of a new type of hollow-core waveguide for CO2 laser radiation guidance is described. This kind of fiber has an air core surrounded by an oxide-glass cladding which for Ary10.6 μm exibis a complex refractive index with real part <1. Curves of the measured reflectivity and real and immaginary part of the refractive index for glass samples with different PbO percentage are shown, along with attenuation measurements performed on fiber drawn from such glasses.

Characterisation of single-mode fibres by near-field measurement

Abstract: A new technique for the determination of the refractive-index profile of single-mode optical fibres from a simple near-field measurement is proposed. This permits one to deduce accurately all the important parameters of the fibre.

Mode-field expansion and reduction in dispersive fibers by local heat treatments

Abstract: A novel method is proposed to make the mode-field expander and reducer using dispersive fibers which are fabricated from optical glasses with different transformation temperatures and index reductions caused by rapid cooling. The dispersive fibers are heated locally at low or high temperatures, and the index difference is decreased or increased at the heated part. The mode-field is confined weakly or strongly in the core owing to the reduced or raised index difference, and is expanded or reduced partially.