Tunable fiber Bragg grating phase shift by simple pressure packaging

An accurate fiber Bragg grating (FBG) phase-shift tuning system is proposed and demonstrated. It depends on a localized pressure applied to a specially packaged FBG filter using an accurate micrometer single-axis stage. Continuous range of phase shift from 0 to ππ is achieved with linear relation to the stage position. An acceptable degree of repeatability of the process is noticed in the experiment.