Rapid thermal sensors with high resolution based on an adaptive dual-comb system

We report a high-resolution rapid thermal sensing based on adaptive dual comb spectroscopy interrogated with a phase-shifted fiber Bragg grating (PFBG). In comparison with traditional dual-comb systems, adaptive dual-comb spectroscopy is extremely simplified by removing the requirement of strict phase-locking feedback loops from the dual-comb configuration. Instead, two free-running fiber lasers are adopted as the light sources. Because of good compensation of fast instabilities with adaptive techniques, the optical response of the PFBG is precisely characterized through a fast Fourier transform of the interferograms in the time domain. Single-shot acquisition can be accomplished rapidly within tens of milliseconds at a spectral resolution of 0.1 pm, corresponding to a thermal measurement resolution of 0.01 °C. The optical spectral bandwidth of the measurement also exceeds 14 nm, which indicates a large dynamic temperature range. It shows great potential for thermal sensing in practical outdoor applications with a loose self-control scheme in the adaptive dual-comb system.