Broadband Chaos generation using three-stages-cascaded semiconductor lasers in a ring topology

Chi-Hong Tu^1*, Yu-Han Hung¹

¹Department of Photonics, National Sun Yat-sen University, Kaohsiung city, Taiwan

* Presenter:Chi-Hong Tu, email:baseball08090809@gmail.com

We investigate a three-stage cascaded optical injection system configured in a ring topology in this work. Since the dynamic behavior of semiconductor lasers can be manipulated by various injection parameters, such as detuning frequency and injection intensity, each injected semiconductor laser in the cascaded system can be operated independently with different nonlinear dynamics. By adjusting the detuning frequency and injection intensity at each stage, we observe strong nonlinear interactions that drive the system from stable oscillation into broadband chaotic dynamics. As will be shown, the chaotic output exhibits a continuous spectrum that extends beyond 125 GHz, which is approximately 1.4 times broader than the spectrum of semiconductor lasers with a single-stage optical feedback scheme. This setup offers a simple and flexible approach to studying high-dimensional nonlinear dynamics, and the resulting broadband chaos can be beneficial for fast random number generation and secure photonic communication systems.

Keywords: DFB laser, Cascaded system, Broadband Chaos, Microwave photonics