High-sensitivity broadband micro-Michelson-interferometer based on an end-sphered hollow-core fiber

We demonstrate a high-sensitivity broadband micro-Michelson fiber interferometer using a singlemode fiber end-spliced with a short (43.9μm) hollow-core end-collapsed lensed fiber. The extinction ratio can be above 25 dB over the 1250-1650 nm wavelength range.