Transverse-Stress Fiber Bragg Grating Sensor With High Spatial Resolution and Temperature Stability

We demonstrate a new method for measuring transverse stress with 10.2-mum spatial resolution in a fiber Bragg grating sensor, without the use of polarization-maintaining fiber, by combining a four-state polarization analysis with a layer-peeling algorithm. Measurements of the externally induced birefringence agree well with predicted values. We also demonstrate that our measurement is insensitive to temperature changes and spatial gradients, making it ideal for nonisothermal applications.