Fully On-Chip Integrated Photodetector Front-End Dedicated to Real-Time Portable Optical Brain Imaging

• 作者: Ehsan Kamrani Frederic Lesage Mohamad Sawan
• 来源期刊: 光学与光子学期刊(英文)
• 学科: 医学
• 关键词: BIOCHIP Analog CMOS INTEGRATED Circuit Trans-Impedance Amplifier FNIRS Brain IMAGING Medical IMAGING OPTICAL Sensors
• 年，卷（期）: 2012,（4）
• 页码范围: 300-313
• 页数: 14页
• 分类号: R73

摘要

Optical brain imaging using functional near infra-red spectroscopy (fNIRS) offers a portable and noninvasive tool for monitoring of blood oxygenation. In this paper we have introduced a new miniaturized photodetector front-end on achip to be applied in a portable fNIRS system. It includes silicon avalanche photodiodes (SiAPD), Transimpedance amplifier (TIA) front-end and Quench-Reset circuitry to operate in both linear and Geiger modes. So it can be applied for both continuous-wave fNIRS (CW-fNIRS) and also single-photon counting. Proposed SiAPD exhibits high-avalanche gain (>100), low-breakdown voltage ( V) and high photon detection efficiency accompanying with low dark count rates. The proposed TIA front-end offer a low power consumption ( mW), high-transimpedance gain (up to 250 MV/A), tunable bandwidth (1 kHz - 1 GHz) and very low input and output noise (~few fA/√Hz and few μV/√Hz). The Geiger-mode photon counting front-end also exhibits a controllable hold-off and rest time with an ultra fast quench-reset time (few ns). This integrated system has been implemented using submicron (0.35 μm) standard CMOS technology.