Analytical expression of core and cladding material losses effect in Bragg fibers using the perturbation theory

Abstract

We present an analytical expression of fiber loss caused by core and cladding material losses for the TE mode of hollow-core and nonhollow-core Bragg fibers using the perturbation theory. The fiber loss agrees well with previous numerical results. Under the quarter-wave stack (QWS) condition, the expression gives the explicit dependence of the fiber loss on the fiber structural parameters, the wavelength, and the mode. The combined effect of the material with the confinement losses is also studied. It is quantitatively revealed that the core material loss affects the fiber loss much more than the cladding material losses, depending on the optical power confinement factor. The position of the minimum fiber loss corresponds well to the condition satisfying a generalized QWS condition even in the nonhollow-core Bragg fibers.

Design and Analysis of Ultra-Wideband Highly-Birefringent Bragg Layered Photonic Bandgap Fiber With Concave-Index Cladding

“…Meanwhile, considering Bragg fibers and OmniGuide fibers [18,19], the fiber core is normally surrounded by a multilayer cladding that consists of alternating layers having high contrast indices of refraction, allowing the light propagation in UV and far-infrared regions. The high and low indices in these periodic coaxial claddings are generally realized by different materials, such SiN and metal, instead of silica, which would bring along fiber fabrication challenges and loss issues.…”