Design of Mode-Dependent-Loss Controller Using Long Period Fiber Grating with Coating Material for 2LP-Mode Transmission System

We designed a mode equalizer to handle mode-dependent loss (MDL) in mode division multiplexing systems. The proposed equalizer is based on a step-index long-period fiber grating (LPFG) and designed to attenuate the LP 01 core mode while providing high transmission of the LP 11 core mode. For a practical fiber design, we assumed a coating material with a higher refractive index than the cladding. Consequently, numerous leaky cladding modes should be analyzed. This study focuses on identifying the optimal core parameters to efficiently equalize MDL.