Multiple Axis Strain Sensing Using Fiber Gratings Written onto Birefringent Single Mode Optical Fiber

Dual overlaid fiber gratings were written onto polarization preserving fiber and used to measure two axes of transverse strain by measuring peak to peak spectral separation between fiber gratings along each of the birefringent axes. This paper summaries transverse sensing results and describes extensions to allow measurement of longitudinal strain and temperature to for a single point three axis strain and temperature sensor.