Optimization of multicore fiber for high-temperature sensing.

We demonstrate a novel high-temperature sensor using multicore fiber (MCF) spliced between two single-mode fibers. Launching light into such fiber chains creates a supermode interference pattern in the MCF that translates into a periodic modulation in the transmission spectrum. The spectrum shifts with changes in temperature and can be easily monitored in real time. This device is simple to fabricate and has been experimentally shown to operate at temperatures up to 1000°C in a very stable manner. Through simulation, we have optimized the multicore fiber design for sharp spectral features and high overall transmission in the optical communications window. Comparison between the experiment and the simulation has also allowed determination of the thermo-optic coefficient of the MCF as a function of temperature.