Measurement of high-speed and wide range spectral dynamics based on a self-calibrated ultrafast swept laser

Blazed-grating-based tunable filters often struggle to achieve both narrow bandwidth and high optical throughput during high-speed wavelength sweeping. Furthermore, existing characterization methods are mostly suited for static or low-speed conditions and lack the calibration mechanisms needed to accurately capture spectral dynamics on the nanosecond scale, which limits further improvements in dynamic performance. This paper presents a high-speed, widely tunable optical filter based on a Littrow-configured blazed grating, featuring flat amplitude response and narrowband filtering. By incorporating an asymmetric cat’s-eye lens collimation system, the inherent trade-off between filtering bandwidth and light collection efficiency is effectively resolved. Leveraging wavelength-time mapping of an ultrafast swept laser and a resampling calibration algorithm, real-time characterization of the filter’s spectral dynamics over a range exceeding 100 nm is achieved. The filter demonstrates an insertion loss below 6 dB across a continuous tuning range of 216 nm, with a stable 3 dB bandwidth of approximately 1.94 nm. Even at sweeping speeds as high as 2.84×10 6 nm /s, it maintains excellent tuning linearity ( R 2 >0.99996) and bandwidth stability. This work provides a solution and dynamic characterization methodology for high-speed optical sweeping devices, paving the way for applications in high-speed optical sensing, swept-source optical coherence tomography, and ultrafast spectral measurements.