GEOSWIFTS - Application of an Optically Integrated Spectrometer to Strain Measurement Using Bragg Sensors

We have developed and tested a new strainmeter using a low power, field oriented and optically integrated spectrometer coupled to optical fiber Bragg sensors. Different configuration of Bragg sensors may be used, from single Bragg reflector, Fabry-Perot Bragg resonator to Michelson interferometer. The sensitivity of the instrument scale according its length. A 2 cm Fabry-Perot can record down to 50 nanostrain while a 20m Michelson can go down to a few picostrain. We show examples of record obtained with a 3cm Fabry-Perot and a 20m