A low-noise resonant input transimpedance amplified photodetector

We present the design and characterization of a low-noise, resonant input transimpedance amplified photodetector. The device operates at a resonance frequency of 90 MHz and exhibits an input referred current noise of 1.2 $pA/Hz$—marginally above the theoretical limit of 1.0 $pA/Hz$ set by the room temperature Johnson noise of the detector’s 16 kΩ transimpedance. As a result, the photodetector allows for shot-noise limited operation for input powers exceeding 14 µW at 461 nm corresponding to a noise equivalent power of 3.5 $pW/Hz$⁠. The key design feature which enables this performance is a low-noise, common-source junction gate field-effect transistor amplifier at the input which helps to reduce the input referred noise contribution of the following amplification stages.