Asymmetrically infiltrated twin core photonic crystal fiber for dual-parameter sensing

• The asymmetric infiltration twin core PCF structure is novel.
• The sensor has a high temperature sensitivity of 1.23 nm/°C.
• The sensor is capable of measuring temperature and strain simultaneously.
• Sensor structure is compact.

We demonstrate a fiber-optic dual parameter sensor based on a water filled Mach–Zehnder interferometer. Such a sensor is fabricated by asymmetrically infiltrating a twin core photonic crystal fiber with water, and splicing it between single mode fibers. Two sets of interference fringes which result from multi-mode interference are obtained by such a structure. By measuring the wavelength shift of the small fringe and the big envelop of the spectrum, strain and temperature can be determined simultaneously.