Fast-scanning dispersion-adjustable reference delay for OCT using fiber Bragg gratings

We report on the use of two matched linearly chirped fiber Bragg grating (FBG) in the reference arm of a Michelson interferometer as a means to achieve variable optical delay. We demonstrate that the properties of a linearly chirped FBG can be exploited to achieve millimeters of optical delay with physical stretches of the FBG on the order of tens of microns; this allows for optical delay line configurations that are easily driven by piezo-electric actuators.