High-temperature sensing using surface relief fiber Bragg gratings

We present a new type of fiber Bragg grating (FBG) that can be used in high-temperature sensing applications. We use the flat side of a D-shaped optical fiber as a platform to etch the grating into the surface of the fiber. Because the grating becomes a physical feature of the fiber, it is not erased at high temperatures as are standard FBGs. These surface relief fiber Bragg gratings will operate up to high temperatures. We provide a brief explanation of the fabrication process and present our results for operation up to 1100/spl deg/C.