Few-Mode Erbium-Doped Fiber Amplifier With High Gain and Low Differential Modal Gain for Mode-Division-Multiplexed Systems

The increasing development of information technology has led to a higher demand for communication capacity. Moreover, the mode division multiplexing (MDM) is considered one important technologies expand optical fiber transmission capacity, and few-mode erbium-doped amplifier (FM-EDFA) main device applied loss compensation under long-haul systems. This paper reports design characterization six-mode (6M-EDFA) MDM A center-depressed with trench-assisted structure, designed adjustment relevant parameters reduce splice between (6M-EDF) fiber. results show lowest theoretically 0.293 dB. By analyzing field distribution, two erbium ion doping regions are initially identified, ring region further layered, concentration three layers optimized achieve high gain low differential modal (DMG) using genetic algorithm (GA). In case core forward pumping LP 01 at 1480 nm, simulation that average 25.7 dB DMG 0.277 obtained 1550 nm considering coupling. 6-mode system built fully verify performance meet requirements system.