Graded index multimode fibre as saturable absorber induced by nonlinear multimodal interference for ultrafast photonics

Abstract

Abstract Graded index multimode fibre (GIMF) has emerged as a promising platform for two- and three-dimensional nonlinear optics. Based on the nonlinear multimodal interference technique, GIMF has demonstrated the saturable absorption effect and applied for fibre-based-laser short pulse generation as versatile, wideband ultrafast optical switches. Herein, this review presents the basic principles and the optical properties of the GIMF-based saturable absorber (SA). With this proposed GIMF-based SA device, mode-locking fibre lasers in the wavelength range of 1, 1.55, and 2 μ m are realized. Particular focus is on the tunable and multi-wavelength mode-locked fibre lasers, various kinds of soliton generation and large energy soliton generation and a detailed summary of the current advances are given.