Ultra-high resolution and large range on-chip Fano-enhanced thermometer based on spectral analysis

摘要: Temperature detection is essential for evaluating the working condition of various physical, biological, and chemical systems. Optical temperature sensing tools, particularly resonator-based thermometers, have garnered significant attention due to their exceptional performance in selectivity, sensitivity and anti-electromagnetic interference. Recently developed thermometers based on optical whispering-gallery mode barcodes of the microbubble resonator achieve a large temperature range measurement and direct temperature readout. However, the large temperature variation may potentially result in inaccurate results due to similarities in spectra and inadequate precision caused by nonlinear collective shift. In this work, we have developed a novel and directly readable on-chip silicon-based Fano-enhanced thermometer utilizing a Mach-Zehnder interferometer configuration. The device comprises a fishbone waveguide and a curved strip waveguide coupled with an ultra-high Q racetrack microring resonator. The spectrum patterns of the thermometer are uniquely determined by the temperature and exhibit ultra-high slope ratio Fano resonances of over 2.0 ×104 dB/nm. Simultaneously, we have proposed a spectral analysis method to accurately derive actual temperatures, which enables an ultra-high detection resolution of 6.1×10–4 ℃ and a large measurement range of 65 ℃ by leveraging a temperature database. These advancements support precise and extensive temperature sensing applications.