Sub-500-ps Temporal Resolution Streak-Mode Optical Sensor

A streak-mode optical sensor in standard 0.35-μm SiGe BiCMOS technology is presented. The circuit consists of a column of 64 photodetectors coupled to a linear array of transimpedance amplifiers and a 128-deep analog sampling and storage unit. The sweep speed of the sensor is continuously adjustable from 125 ps/pixel to 1 ns/pixel through a closed-loop delay generator. The sensor reaches a total sampling rate of 512 GS/s and a vertical dynamic range of 59 dB. The measured temporal resolution is 465 ps at λ = 400 nm. At λ = 800 nm, this figure is degraded down to 600 ps due to the increased penetration depth of the incident radiation. In a post-processing phase, the frequency response of the system was equalized, allowing the sensor to exhibit sub-500-ps temporal resolution over the entire visible spectrum. The reported streak-mode optical imager is thus suitable for the recording of nanosecond-order transients over a large range of wavelengths and can be used in applications, such as fluorescence metrology, time-resolved spectroscopy, and optical tomography.