ABSTRACT:In this work, we present a novel interferometer based on liquid crystal and photonic crystal fiber technology. The objective of this project is the development of a tunable (switchable) modal (MachZehnder) interferometer for optical communications or sensing. This interferometer has been manufactured splicing a short portion (between 15 and 30 mm) of photonic crystal fiber with two single mode fiber pigtails. The study shows a high sensitivity of the interferometer to the polarization of the launching light..