Abstract
A detailed dynamical analysis of erbium-doped fiber ring laser cavity loss configuration for the chaos message masking scheme is carried out to optimize the generation of high quality chaos. A threefold increase in Lyapunov exponent implying higher security, and a significant increase in chaos bandwidth is achieved, both ideal for secure optical communication and nonlinear chaotic applications. The pulsed chaos is chaotic in a pulse time interval in addition to the amplitude resulting in better concealment of data pulses in a time domain. The chaos spectrum is a flat broadband and rich in spikes making spectral detection of a message more difficult. The range of five key parameters for which erbium-doped fiber ring laser retains its chaotic behaviour is also increased significantly reducing the effectiveness of a brute force attack to guess the erbium-doped fiber ring laser parameters. The chaos message masking scheme provides a higher security in comparison with additive chaos modulation scheme for implementation of chaotic optical communication using erbium-doped fiber ring laser. The security of a complete end-to-end chaotic optical communication system is tested by launching a spectral attack to estimate the message signal. The message signal clearly hides in a stronger chaotic signal and its spectral contents are not discernible.