Experimental Investigation of Nonlinear Dynamics in Single Mode SemiconductorLaser Diodes with Phase Conjugate Feedback

摘要

The semiconductor laser diode offers a unique system to investigate nonlineardynamics when optical feedback is applied. Although there is extensive research of laser diodes with optical feedback from normal dielectric mirrors, very little has been done experimentally to analyze the effects of degenerate phase conjugate feedback from a BaTiO3 crystal. This research experimentally investigated the dynamics of a single-mode laser diode with weak phase conjugate feedback using both the self-pumped and double phase conjugate geometries. The experimental results validated a mathematical model which numerically evaluates the Lang-Kobayahsi coupled differential equations. The model simulated the nonlinear behavior of a laser diode subject to phase conjugate feedback and produced simulated RF and Fabry-Perot spectra of the laser Output. Model and experimental results showed frequency locking between the relaxation oscillation and external cavity frequencies and changes in the relaxation oscillation as a function of cavity length. Resonant behavior in the feedback strength necessary to undamp the relaxation oscillation frequency as a function of the cavity length was also captured experimentally an numerically. Validation of the model and experimental results presented in this research significantly contribute to the understanding of the nonlinear behavior of a laser diode subject to optical feedback.