Low‐Power and Fast‐Scan Reconstructive Spectrometer Chip with pm Resolution on Thin‐Film Lithium Niobate

The demand for wearable devices, chemical sensing, and medical diagnostics has driven rapid development of miniaturized spectrometers. Reconstructive spectrometers can achieve spectral measurements with a high‐resolution and wide bandwidth by utilizing complex mapping of spectra in time or spatial domains. However, achieving reconstruction with a high bandwidth‐to‐resolution ratio still requires long calibration time and large power consumption. Here, an integrated single‐drive reconstructive spectrometer chip is proposed and demonstrated on the thin film lithium niobate platform using hybrid spatial and time speckles. By utilizing long and ultra‐low loss electro‐optic tunable spiral waveguides, 5pm high resolution and 95 nm wide bandwidth for spectral recovery around 1550 nm wavelength are achieved under a voltage scanning of ±50 V. A record‐low peak power of 5.1 µW and energy consumption of 0.252 µJ at a scan rate of 10 Hz is also achieved. Combined with neural network algorithms, the device can perform ultrafast spectral classification within 12.6 µs under driving voltage of only ±3 V, which has great potential in real‐time and low‐power spectral analyses.