Open AccessSpatiotemporal analysis of an all-fiber multimode interference-based saturable absorber via a mode-resolved nonlinear Schrodinger equation
Author(s) -
Guohao Fu,
Jiading Tian,
Tiancheng Qi,
Yulun Wu,
Ying Zhao,
Qirong Xiao,
Dan Li,
Munan Gong,
Ping Yan
Publication year - 2022
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.471143
Subject(s) - multi mode optical fiber , optics , nonlinear schrödinger equation , ultrashort pulse , fiber laser , saturable absorption , mode volume , single mode optical fiber , interference (communication) , materials science , fiber , optical fiber , nonlinear system , physics , laser , plastic optical fiber , telecommunications , computer science , quantum mechanics , channel (broadcasting) , composite material
This paper presents an approach that combines the generalized multimode nonlinear Schrodinger equation with a transmission model to analyze spatiotemporal characteristics of multimode interference in single mode/large mode area fiber-graded-index multimode fiber-single mode fiber (SMF/LMA-GIMF-SMF) structures for the first time. Approximated self-imaging (ASIM) behavior in GIMF and the study of the latter structure used in spatiotemporal mode-locked fiber lasers are first demonstrated. Simulations show that these structures can work as saturable absorbers enabling high-energy pulse output due to nonlinear intermodal interactions and intensity-dependent multimode interference. Otherwise, underlying ASIM is proven that it can perturb the transmission of SMF/LMA-GIMF-SMF, causing instability of their saturable-absorption characteristics. This paper provides a theoretical guide for many applications, such as beam shaping, mode conversion, and high-energy ultrafast fiber laser.