Polarization-maintaining photonic crystal fiber modal interferometer

Abstract

The paper presents an entirely fiber optic Mach-Zehnder interferometer formed in a polarization maintaining photonic crystal fiber (PM PCF). It uses the interference between the polarization modes and the cladding modes. The method of collapsing the air holes in a single segment of the PM PCF was applied to excite the cladding mode from the polarization modes of the PM PCF and create the coupling region of these modes. Measurements of the wavelength spectra of the produced interferometers were performed. The influence of the interferometer length on the period of the wavelength spectrum was investigated experimentally. On the basis of these measurements the difference of the group refractive indices of the polarization modes and the cladding mode was determined. The dependence of the strain sensitivity coefficient of the produced interferometers on the wavelength was determined experimentally. The possibilities of application of the constructed interferometer for sensors are presented.