raw_multi-wavelength_PPG

In this paper, a new photoplethysmography (PPG) bio-sensing system is demonstrated to process higher-quality PPG signals. The proposed bio-sensing system contains four light-emitting diodes (LEDs) in wavelengths of 940, 850, 645, and 523 nm and two photodiodes (PDs). The enhanced biosensing performance is analyzed and designed by optical simulation based on Beer-Lambert law and optimized for maximizing the performance by prudent floor-planning of light transmitter and receiver. The proposed PPG bio-sensing system could significantly improve the key performance parameters such as the pulsatile amplitude(AC) as well as perfusion index(PI) compared with prior arts. The proposed PPG system achieved 2.6, 3.8, and 12.2 times higher PI performance improvement in the multi-wavelength spectrum.