Multi-point high temperature optical fiber sensor

The ability to perform spatially resolved measurement of extreme temperatures, the order of 1000°C and above, would yield enormous benefit to many heavy industrial processes. While optical fibers can provide spatial information along their length through distributed and multi-point sensing techniques, operation at such temperatures is an area of ongoing research and development. A challenge is that conventional optical fibers, fabricated with a chemically doped core, suffer dopant diffusion at these high temperatures, ultimately limiting their operating lifespan. We can overcome this limitation by using specialty pure silica glass fibers, such as microstructured optical fibers. In this work we demonstrate the ability to use such fibers in a significantly multiplexed configuration with twenty fiber Bragg grating sensing elements written via femtosecond laser ablation.