Broadband low-noise photodetector for Pound-Drever-Hall laser stabilization

TL;DR

This paper introduces a simple, high-performance photodetector design for laser stabilization that achieves shot-noise-limited sensitivity at low optical powers, suitable for Pound-Drever-Hall techniques.

Contribution

The authors present a novel photodetector design using a transformer and low-noise RF amplifiers, achieving high gain and low noise for laser stabilization.

Findings

50 MHz bandwidth operation

Gain greater than 10^5 V/A

Input current noise less than 4 pA/√Hz

Abstract

The Pound-Drever-Hall laser stabilization technique requires a fast, low-noise photodetector. We present a simple photodetector design that uses a transformer as an intermediary between a photodiode and cascaded low-noise radio-frequency amplifiers. Our implementation using a silicon photodiode yields a detector with 50 MHz bandwidth, gain $> 10^5$ V/A, and input current noise $< 4$ pA/$\sqrt{\mathrm{Hz}}$, allowing us to obtain shot-noise-limited performance with low optical power.