Low Threshold Optical Bistability and Differential Amplification using a Fiber Amplifier in a Nonlinear Ring Resonator

Optical fiber ring resonators using directional couplers as signal tapping elements are called to play an important role in the future all-optical communication and sensor networks. The possibility of obtaining a wide range of strutures capable of performing wide-band signal processing operations in a guided-wave format has attracted the interest of several research groups. Initial effort focused on structures operating under linear regime showing and demonstrating potential applications as fiber sensors [1], all-fiber lasers [2], Fabry-Perot and Mach-Zehnder interferometers [3], [4], and optical filters for WDM and OFDM [5].