Quantum Cascade Laser Subject to Filtered-phase-Conjugate Feedback: Stability, Root Locus Analysis, and Particle Swarm Optimization

Quantum cascade lasers (qcls) are sources in mid-infrared and terahertz (thz) regions used in the sensing domain and quality control. this paper investigates qcls subject to filtered phase-conjugate feedback (fpcf). instabilities can be detected using the graphical method of pole analysis and the particle swarm optimization algorithm, which allows us to identify and characterize the limitation and critical relations between the laser operating parameters. there is good agreement between the two methods to stability boundaries. the effects of fpcf in comparison with conventional optical feedback (cof), phase-conjugate feedback (pcf), and tilted optical feedback (tof) show that the penetration time factor has a significant and greater influence on the stability of qcl subject to fpcf. these results are in perfect agreement with previous experimental and analytical studies.