Multiplexing dual-parameter sensor using photonic crystal multimode nanobeam cavities

In this paper, we theoretically propose an ultra-compact low crosstalk photonic crystal dual-channel sensor (DCS) for multiplexing dual-parameter sensing. To begin with, a photonic crystal (PhC) elliptical holes multimode nanobeam cavity (EMNC) is designed. By applying three-dimensional finite-difference time-domain (3D-FDTD) simulations, high Q-factors above 1×106 of 0th-order mode and 1×105 of 1st-order mode can be simultaneously achieved. Next, a well-designed equal power splitter, a power combiner and two EMNCs are introduced to form a PhC dual-channel sensor. Based on a sensing matrix, each channel of DCS (EMNC-1 and EMNC-2) can be used in simultaneous detection of refractive index (RI) and temperature independently. Particularly, the total footprint is only about 26.5μm×6.2μm ×0.22μm (length × width × high), which is potentially a promising platform for complex optical multi-sensing network in large scale.