Abstract
A twin-core photonic crystal fiber sensor is proposed for measuring liquid refractive index (RI) and temperature simultaneously. The air holes of the sensor are arranged in a hexagonal pattern, and two planes are introduced by polishing in the cladding. On one side of the plane, the gold film is deposited for RI measurement, and on the other side, the gold film and polydimethylsiloxane (PDMS) are deposited for temperature measurement. We analyzed its sensing characteristics by using finite element method. The numerical results show that the two channels for measuring RI and temperature have no mutual interference. It reduces the complexity of the sensing measurement. The maximum spectral sensitivity of the sensor is 20000 nm/RIU and 9.2 nm/℃, respectively, when the liquid RI is in the range of 1.36-1.42 and the temperature is in the range of 0-50 ℃. The results also show the sensing accuracy was not very sensitive to the change of structural parameters. It hence makes the sensor be easy to fabricate. Our work is very helpful for implementation of a high sensitivity, easy fabrication and real-time multi-parameter SPR sensor.
Carbon-nanotube-deposited photonic crystal fiber for refractive index sensing
