High-performance temperature sensing using a selectively filled solid-core photonic crystal fiber with a central air-bore.

A high-performance temperature sensor based on mode-coupling principle is proposed using a selectively filled, solid-core photonic crystal fiber with a central air-bore. The fibers are fabricated using the "stack-and-draw" method, with a micro scale central bore deliberately kept during the drawing procedure. The addition of the central air-bore enhances the mode-coupling efficiency between the fundamental core mode and modes in the high-index liquid-filled holes in the fiber cladding, therefore, the fiber can be used for a novel sensing architecture, when cladding holes are selectively filled with temperature sensitive liquids. Based on this concept, numerical analyses are accomplished using finite element method, showing that this fiber-based temperature sensor possesses high sensitivity of -6.02 nm/°C, with a resolution of 3.32 × 10^-3 °C, in the temperature range from -80 to 90 °C. The selective hole-filling is verified by a multi-step infiltration technique. A particularly designed probe with improved sensitivity and manipulation is also proposed for this system.