A delay differential eqution NOLM-NALM mode-locked laser model

TL;DR

This paper develops a delay differential equation model for a NOLM-NALM mode-locked laser, incorporating gain medium relaxation and beam asymmetry, revealing stability conditions and pulse regimes through analysis and simulations.

Contribution

It introduces a novel delay differential equation model for NOLM-NALM lasers that includes gain relaxation and asymmetry effects, providing insights into stability and pulse dynamics.

Findings

Stability analysis shows flip instability can be suppressed by modulational instability.

Model exhibits large parameter windows for stable fundamental and harmonic mode-locking.

Numerical simulations reveal regimes with single and multiple pulses per cavity round trip.

Abstract

Delay differential equation model of a NOLM-NALM mode-locked laser is developed that takes into account finite relaxation rate of the gain medium and asymmetric beam splitting at the entrance of the nonlinear mirror loop. Asymptotic linear stability analysis of the continuous wave solutions performed in the limit of large delay indicates that in a class-B laser flip instability leading to a period doubling cascade and development of square-wave patterns can be suppressed by a short wavelength modulational instability. Numerically it is shown that the model can demonstrate large windows of regular fundamental and harmonic mode-locked regimes with single and multiple pulses per cavity round trip time separated by domains of irregular pulsing.