Implementation and Evaluation of SiPM-Based Photon Counting Receiver for IoT Applications

TL;DR

This paper presents an FPGA-based real-time photon counting receiver using SiPMs, achieving high data rates with low error, suitable for IoT and VLC applications, and analyzes the amplifier bandwidth and power trade-offs.

Contribution

Developed a real-time FPGA system for SiPM-based photon counting, demonstrating high data rates and analyzing amplifier bandwidth requirements for IoT optical communication.

Findings

Achieved data rates from 10 kbps to 1 Mbps with BER below 1E-3.

Lower dark count rate or higher data rate reduces power penalty.

Minimum GBP of 120 MHz is needed to approach the Poisson limit.

Abstract

Silicon Photomultipliers (SiPMs) are photon-counting detectors with great potential to improve the sensitivity of optical receivers. Recent studies of SiPMs in communication focus on the speed rather than the power consumption of the receiver. The gain bandwidth product (GBP) of the amplifiers in these post-SiPM readout circuits is significantly higher than the target data rate. Additionally, the SiPM experiments for optical communication are performed using an offline method which uses instruments including oscilloscopes and personal computers to process chunks of the transmitted data. In this work, we have developed an embedded real-time field-programmable gate array (FPGA) based system to evaluate a commercially available 1 mm-sq SiPM. The implemented real-time system achieves data rates from 10 kbps to 1 Mbps with a bit error rate (BER) below 1E-3 approaching the Poisson limit. Results showed that reducing either the dark count rate or increasing the data rate leads to lower dark counts per bit time, hence less power penalty to maintain a probability of error (PE) of 1E-3. The numerically simulated results indicated that to maintain the Poisson limit, the minimum GBP of the amplifier in the post-SiPM readout circuit is 120 MHz based on the proposed setup within the tested data rates. This GBP limitation is determined by the noise floor of the read-out circuit. The analysis of the minimum GBP and electrical power consumption of the receiver in photon counting and BER enables the potential future adoption of this receiver technology when high optical sensitivity is required, such as visible light communications (VLC) for low data rate Internet of Things (IoT) applications.