Abstract
All optical fibers, including single-mode, multimode, and multicore fibers, exhibit some degree of birefringence, either purposely, such as in polarization-maintaining fibers, or inadvertently due to material or fabrication imperfections. Finding a low-complexity method to accurately calculate the modal characteristics of elliptical fibers has been a long-standing problem. We present a novel accurate perturbative method that avoids the difficulties associated with the traditional Mathieu function treatment. The method is also applicable to a broader class of oscillating systems with elliptical geometry.
Highlights
The accurate determination of transverse modes of elliptical waveguides is important for both deliberately elliptical waveguides, such as polarization-maintaining fibers, and in the context of circular fibers due to core shape fluctuations caused by manufacturing imperfections [1]
The angular Mathieu functions are expressed as Fourier series and the radial functions as series of products of Bessel functions, and the coefficients for the terms are obtained by calculating the eigenvectors of an infinite matrix
The determination of transverse modes of step-index waveguides requires the matching of tangential fields at the core
Summary
The accurate determination of transverse modes of elliptical waveguides is important for both deliberately elliptical waveguides, such as polarization-maintaining fibers, and in the context of circular fibers due to core shape fluctuations caused by manufacturing imperfections [1]. The deviations of the field profile F from the circular case are given by the higher order terms F n obtained by solving Eq (5), which is a driven Helmholtz equation. Note that for δ ≠ 0 the zeroth-order term F 0 is already different from the circular waveguide modes as it has been scaled in the x dimension.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
