Accurate theoretical prediction for single-mode fiber macrobending loss and bending induced polarization dependent loss

For an all-fiber edge filter used in a rapid wavelength measurement system for optical sensing, a low polarization dependent loss (PDL) is required to ensure high measurement accuracy. The calculation of the bend loss for the TE and TM modes based on scalar approximations results in a discrepancy between the calculated PDLs and measured results. Here a full vectorial finite difference beam propagation method (FV FD-BPM) is used to compute the complex propagation constant and the field distributions of the TE and TM modes in the bending fiber, allowing the accurate calculation of the PDL of bending fiber.