Time-delay signatures in chaotic semiconductor ring lasers with cross mutual injection

The time-delay (TD) signatures of chaos in semiconductor ring lasers with cross mutual injection are investigated numerically. The TD signature is quantified via auto-correlation function. The injection parameter regions contributing to successful TD concealment are identified. It is shown that, higher injection strengths can be utilized for larger frequency detuning to achieve TD concealment, and the region contributing TD concealment exhibits V type in the parameter space. The chaotic SRL with TD signature suppression is highly desirable for chaotic communication systems and high speed random number generators integrated on photonic integrated circuit.