Fiber-chirped grating Fabry-Perot sensor with multiple-wavelength-addressable free-spectral ranges

We report the demonstration of a fiber-chirped grating Fabry-Perot (FP) sensor with large dynamic range and high resolution surpassing that of a conventional FP sensor. The chirped grating FP sensor functions as an array of collocated FP cavities with different wavelength addressable cavity lengths or free-spectral ranges. This sensor design allows large dynamic range and high resolution to be achieved in a single compact sensor head. Free-spectral range from 0.04 to 1.3 nm has been achieved. Using this device as a strain sensor, unambiguous (without fringe counting) strain measurements from 3/spl plusmn/1 μstrain (limited by probe source resolution) to 1300 μstrain have been measured.