Polarization maintaining fiber interferometer based on superimposed Mach-Zehnder and Sagnac interferences and its application

摘要

A novel polarization maintaining fiber interferometer based on superimposed Mach-Zehnder and Sagnac interferences is presented. Higher order cladding modes are effectively excited to construct a Mach-Zehnder interference with the low order linear polarized modes in the Sagnac interferometer when fusing the single mode fiber and polarization maintaining fiber with a peanut structure. We also demonstrate its strain and temperature tunability. The Mach-Zehnder resonance peak is strain insensitive while the Sagnac resonance dip is highly sensitive to strain, and the Mach-Zehnder resonance peak exhibits an opposite thermal response compared to the Sagnac resonance dip. This can be applied for dual parameter measurement with high resolutions.