A semi-analytical calculation method of bending loss for large-mode-area fibers with arbitrary refractive-index profile

Predicting mode-dependent bending loss is important for large-mode-area (LMA) fibers to strip out unwanted modes. In order to seek a reasonable calculation method, a new bending loss formula that allows for both mode field distortion and weaker mode confinement was derived in detail. Based on the formula, a semi-analytical method was introduced to calculate the mode bending loss for LMA fibers. By combining the applications of the finite element method, discrete Fourier transforms and numerical integral, the method is valid for LMA fibers with arbitrary refractive index profile. The obtained loss characteristics are basically consistent with the previous results. This accordance demonstrates the feasibility and generality of the semi-analytical method.

Research Highlights
► We derive a new bending loss formula in detail.
► We introduce a semi-analytical calculation method of mode-dependent bending loss for LMA fibers.
► The semi-analytical method integrates the applications of finite element method, discrete Fourier transforms and numerical integral.
► It is valid for the LMA fibers with arbitrary refractive index profile.