| We studied, experimentally and theoretically, the nonlinear and chaotic dynamics of a bidirectional class-B ring, laser operating in a single-mode in each direction, when the pump intensity is modulated by a square-wave signal. The equations of motion for the electric field amplitudes and population inversion Fourier components are derived using a semi-classical model. In addition to the coupling of modes via the gain medium, the model includes coupling of the two oppositely directed modes via backscattering. These equations are solved numerically and the dependence of various dynamical features on the depth and frequency of modulation is investigated. We find that the system is capable of exhibiting periodic, quasi periodic and chaotic behaviors as the depth and frequency of modulation are varied.; Two maps for the dynamical behavior of the system, as reflected in the mode intensities, as functions of the frequency and depth of modulation were constructed. In one map we recorded whether the dynamical behavior is periodic, quasi-periodic, or chaotic. In the other map we recorded the state of synchronization of the two counter-propagating signals.; Lyapunov exponent spectrum was computed using the Jacobian method and the variation of the maximal Lyapunov exponent with modulation depth and modulation frequency was studied.; The model system was investigated experimentally using a diode laser pumped Nd-Yag ring laser system. Experimental results confirm the non-linear dynamical features predicted by the theoretical model presented in the thesis. A detailed comparison of the experimental and theoretical results shows reasonable agreement in most cases. Certain discrepancies between the two in the chaotic regime are attributed to spontaneous emission noise which is not included in the model.; Suggestions for further work inspired by the results of this thesis conclude this work. |
