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

A streak-mode optical sensor in standard 0.35- 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 nm. At 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.