Analysis of a lensed coreless fiber by a hybrid technique combining FD-BPM and FD-TDM

A technique connecting a scalar wide-angle finite-difference beam-propagation method (FD-BPM) with a scalar finite-difference time-domain method (FD-TDM) is systematically described and used to analyze a lensed coreless fiber. The propagating field and its phase distribution are calculated to demonstrate the phase adjustment effect of the lens. The power concentration due to the lens is evaluated by the directive gain used in the antenna engineering. The effect of an antireflection coating on the reflected power is also evaluated.