A Comparison of APD- and SPAD-Based Receivers for Visible Light Communications

Abstract

Visible light communications (VLC) is an alternative method of indoor wireless communications that requires sensitive receivers. Ideally, single photon avalanche detectors (S PADs) could be used to create more sensitive receivers. However, the dead-time, finite output pulse width and photon detection efficiency of existing S PAD arrays limits their sensitivity and bandwidth. In this paper an accurate equation for the impact of dead-time on the sensitivity of a S PAD array is presented. In addition the impact of the width of the output pulses on the on-off keying (OOK) data rate is investigated. Finally, a comparison between receivers containing an APD and a large array of S PADs shows that although the receiver containing the S PAD is more sensitive in the dark the APD-based receiver is more sensitive in normal operating condition. However, the models that predict the performance of both receivers suggest that newer S PAD arrays will enable significant improvements in receiver sensitivity.

Distortion losses of high-speed single-photon avalanche diode optical receivers approaching quantum sensitivity

“…With 230 pJ/b at best performance, we prove the highest power efficiency of SPAD RXs published to-date [6,10,11]. Although the RX energy per bit is not lower than PD/APD RXs (ranging from 86 pJ/b in [1] to 129 pJ/b [3]), these do not include an ADC function, which is inherently realized by this SPAD RX architecture.…”

Underwater Optical Wireless Communications: Overview

“…The great advantage of SPADs is that their detectors do not need to a trans-conductance amplifier. This intrinsically leads to the fact that optical communications implemented with this kind of diodes can provide high detection, high accuracy and low noise measurements [119][120][121][122][123][124][125][126][127][128][129][130][131][132]. RX sensors based on SPADs still require further in-depth studies.…”

Adaptive Software Defined Equalization Techniques for Indoor Visible Light Communication

“…Apart from different concentrators, a fly-eye receiver can be used [53] or even an advanced form of an angle diversity receiver, which is often combined with beam steering technology [54,55]. Zhang et al [56] compared APD and single photon avalanche diode (SPAD)based receivers, which are also often used in experiments. APD showed promising results, but it tends to be pricy for mass deployment.…”