Highly Sensitive SPAD-Based Receiver for Dimming Control in LiFi Networks

Area of Science:

• Optical Communications
• Wireless Networking
• Photonics

Background:

• Visible Light Communication (VLC) systems offer integrated illumination and data transmission.
• Dimming control in VLC necessitates sensitive receivers, particularly for low-light conditions.
• Single-Photon Avalanche Diodes (SPADs) enhance receiver sensitivity but suffer performance degradation due to dead-time effects at higher light intensities.

Purpose of the Study:

• To propose and evaluate an adaptive SPAD receiver for reliable VLC operation under diverse dimming levels.
• To mitigate the non-linear effects of SPAD dead time in VLC systems.
• To assess the receiver's performance with different modulation schemes, including OOK and OFDM.

Main Methods:

• An adaptive receiver design incorporating a Variable Optical Attenuator (VOA) to regulate incident photon rates.
• Integration of the VOA to maintain SPAD operation within optimal conditions.
• Performance evaluation using Binary On-Off Keying (OOK) and Orthogonal Frequency Division Multiplexing (OFDM) modulation schemes, including DCO- and ACO-OFDM.

Main Results:

• The adaptive SPAD receiver demonstrates superior performance compared to conventional PIN PD and SPAD array receivers.
• Significant improvements in Bit Error Rate (BER) and achievable data rates were observed.
• The receiver ensures reliable operation across various dimming levels and modulation techniques.

Conclusions:

• The proposed adaptive SPAD receiver effectively addresses the challenges of dimming control in VLC systems.
• Adaptive optical attenuation is crucial for optimizing SPAD performance in dynamic light environments.
• The adaptive receiver offers a robust solution for enhancing VLC system reliability and data throughput.