基于侧边耦合一维光子晶体微腔的高分辨率光子温度计

Aiming at in-line coupled one-dimensional photonic crystal (1D PhC) microcavity with high quality factor (Q) but extremely low transmittance, a side-coupled 1D PhC thermometer with high resolution, signal to noise ratio and dynamic range was proposed. Through modulating reflection coefficient of photonic crystal units and overlap of mode field between the microcavity and coupling waveguide, the Q and transmittance of the PhC device were improved. The total Q-factor, sensitivity, extinction ratio, and mode spacing between fundamental and secondary mode of the fabricated PhC device were 2.7×10⁴, 65.6 pm/℃, 0.45 and 18.5 nm, respectively. By adopting a sweep frequency measurement technique, the resolution of the proposed photonic thermometer reaches millikelvin and the sensing range is over 280 ℃.