Gain Equalization for Few-Mode Erbium-Doped Fiber Amplifiers via Strong Mode Coupling

Abstract

Few-mode erbium-doped fiber amplifiers (FM-EDFAs) are one of the most important optical subsystems for successful space division multiplexed transmission systems. In this paper, we propose a new FM-EDFA designed to achieve significantly reduced differential modal gain (DMG) via strong mode coupling. Using a new numerical model based on a fiber transfer matrix, the DMGs of FM-EDFAs are systematically investigated and two different types of six-mode fiber amplifiers are analyzed, as exemplar demonstrations. In a uniformly doped step-index fiber, the DMG can be reduced from 9.3 to 1.1 dB (i.e., 8.2 dB reduction) and further reduced to 0.5 dB in a dual-layer doping structure.

High-Speed Optical Fiber Communication in China

“…We will brief on the research contents of those major national projects. Projects of optical fiber transmission on ultrahigh-speed optical fiber communications include single-channel Tb/s 1000 km transmission, − P bit/s WDM signals 1000 km transmission, − 100 Tb/s 1000 km transmission, − few-mode multicore transmission systems, − 17-core three-mode transmission systems, − hollow fibers, − amplifiers for new bands, − and few-mode amplifiers. − The following will elaborate on several representative projects.…”