This thesis studies, both practical and theoretical, aspects of the synchronisation locking process of two external-cavity semiconductor lasers, optically coupled in a Master- Slave configuration. Such configurations have been the subject of a significant number of numerical and experimental investigations, mainly motivated by the desire to develop a secure communications scheme.
This thesis investigates the robustness of the chaos synchronisation process to parameter mismatch with regard to both experimentally adjustable parameters ((optical injection ramping time between 0.4 ps and 10 ns, and optical injection strength between 3 and 164 ns-¹ ), and a range of intrinsic laser diode parameters (carrier lifetime between 2 and 4 ns, and linewidth enhancement factor between 4.0 and 6.5). A multiple averaging approach was adopted as a means of ascertaining the global effect these parameters have on the locking process. The dynamics induced by an introduced optical chopper to the injection arm were investigated for the first time and a previously unreported switching processes observed.
The spectral and temporal dynamics of both the TE-TM emission were investigated in an external-cavity laser diode configuration where the optical feedback was sufficient to induce chaotic oscillations. Specifically, the TM mode was observed to lase at various levels of feedback. Three possible explanations of the instabilities seen in the recorded spectra and the corresponding L-1 curves were provided.