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.

Hollow-Core Photonic Crystal Fibre

Abstract: A hollow core photonic crystal fibre (HCPCF) having a wavelength of operation, the HCPCF comprising: a core region having a first refractive index; a cladding region surrounding the core region and comprising a plurality of microcapillaries arranged in a transverse structure having a pitch, the pitch of the structure being at least five times larger than the wavelength of operation, the cladding region having a second refractive index higher than the first refractive index.

Analysis of Straight Periodic Segmented Waveguide Using the 2-D Finite Element Method

Abstract: A numerical analysis of periodic segmented waveguides (PSWs) using the 2-D finite element method (2D-FEM) in the frequency domain is presented. This method has significantly lower computational cost when compared with 3-D methods that have been used to model PSWs, and can also model back reflected signals. Unlike photonic crystal waveguides, light confinement in a PSW is due to total internal reflection as in a continuous waveguide (CWG). We show that the dispersion relation of the guided modes in PSW is strongly influenced by the dielectric periodicity along the waveguide. We calculate the mode profile of a PSW in a region far away from the bandgap and we showed that it is comparable to the mode profile of the equivalent CWG even for relatively high values of averaged refractive index contrast.

Fiber optic coupler exhibiting low nonadiabatic loss

Abstract: A fiber optic coupler comprising a plurality of single-mode optical fibers, each of which is tapered to form a small diameter sections that extends in contiguous relationship with the small diameter sections of the other fibers to form a coupling region. Each of the fibers has a core surrounded by a cladding of refractive index lower than that of the core. At least one of the fibers has a refractive index pedestal of refractive index ni between said core and cladding, wherein n1>ni>n2, n1 and n2 being the refractive indices of the core and cladding, respectively.

Optical fiber with built-in grating and optical fiber for forming grating therein

Abstract: The present invention provides an optical fiber equipped with a grating that functions as a narrow-band loss filter. The optical fiber has a core, an inner cladding, an intermediate cladding, and an outer cladding, which have refractive indexes n0, n1, n2, and n3, respectively, the refractive indexes having a relationship of n0>n3≧n1n2. At least a part of the inner cladding has a grating. The refractive index of the intermediate cladding is lower than the refractive indexes of the inner cladding and the outer cladding such that a recession is formed in the refractive index profile of the clad. The grating is provided on the inner side relative to the recession.