Abstract
The level of security in a chaotic optical communication system depends upon the degree of chaos which is measured by the value of positive Lyapunov Exponent (LE) spectrum. A comparative investigation to question the degree of chaos acquired in different schemes of Erbium Doped Fiber Ring Laser (EDFRL) and semiconductor laser is presented. The analysis based on the statistical average of various simulation results reveals that semiconductor laser with optoelectronic feedback produces highest degree of chaos as compared to EDFRL schemes. Furthermore, pulsed chaos is better than non-pulsed chaos in terms of unpredictability as dictated by the measure of LE.