Ultra-compact Mach-Zehnder interferometer using hollow optical fiber for high temperature sensing

We have developed a compact and stable fiber optic Mach-Zehnder interferometer (MZI) using hollow optical fiber (HOF) spliced between standard single mode fibers. The use of a micro-sized air hole in HOF is to provide two optical guidance/propagation paths and temperature sensitivity of 52 pm/°C and dynamic range of 10 dB are obtained over the range of 25°C to 330°C at 1550 nm.