TY - JOUR TI - Delay differential equations enriched with nonlinear gain compression for passively mode-locked semiconductor lasers AU - Simos, C. AU - Simos, I. AU - Georgiou, G. JO - Optical and Quantum Electronics PY - 2021 VL - 53 TODO - 1 SP - null PB - Springer-Verlag SN - 0306-8919 TODO - 10.1007/s11082-020-02688-9 TODO - Differential equations; Fabry-Perot interferometers; Mode-locked fiber lasers; Passive mode locking; Semiconductor lasers; Ultrafast lasers, Delay differential equations; Fabry-Perot cavity; Gain/absorption; Nonlinear gains; Original model; Passively mode-locked; Short pulse generation; Travelling waves, Nonlinear equations TODO - Non-linear gain compression is well-known to play an important role in the dynamics of short-pulse generation and propagation in semiconductor lasers. Here, a previously reported delay differential equation model for passively mode-locked semiconductor lasers is enhanced with nonlinear gain compression terms in gain and absorber sections. We report the modified model equations and show the impact in gain/absorption dynamics with respect to the original model. In addition, we perform an extended comparison between the enriched delay differential equation model applied on a ring cavity and a travelling wave model applied on an equivalent Fabry-Perot cavity, highlighting the limits of quantitative and qualitative agreement between the two approaches. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature. ER -