Tunable birefringent phase shift induced in fiber Bragg gratings by a shape memory alloy phase modulator

摘要

We propose a new method to induce low loss tunable birefringent phase shifts in fiber Bragg gratings (FBG) by applying mechanical stresses at precise locations along the FBG. A specially designed shape memory alloy (SMA) ferrule is used to transfer mechanical stress to the optical fiber. A piezoelectric actuator control the amount of stress delivered to the fiber by the SMA ferrule, thus allowing a precise and dynamic tuning of the amplitude of the phase shift induced in the FBG. A distributed feedback (DFB) fiber laser based on this phase modulator is also introduced.