Nonlinear wave propagation in optical fiber is a rich and fascinating subject. From a purely-scientific point of view, fibers provide convenient and reproducible experimental settings for a broad range of nonlinear dynamical processes. Qualitatively new phenomena are still being discovered.
Gases-based nonlinear optics overcomes several challenges in solid-core fiber optics, as well as exhibiting interesting physical phenomena, due to its low nonlinearity and distinct physical properties from solids. There are thus a lot waiting to be discovered.
Mode-locked fiber lasers with Mamyshev mechanism and gain-managed nonlinear dynamics can generate sub-50 femtosecond pulses with record-high pulse energy. Gain-managed nonlinear amplifier (GMNA) reaches ~1 µJ pulse energy and sub-50 femtosecond pulses. Better performance fiber lasers and fiber amplifiers are still being developed.