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

DOI: 10.4236/opj.2012.24037   PDF   HTML     5,784 Downloads   12,483 Views   Citations

Abstract

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 (<12 V) and high photon detection efficiency accompanying with low dark count rates. The proposed TIA front-end offer a low power consumption (<1 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.

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E. Kamrani, F. Lesage and M. Sawan, "Fully On-Chip Integrated Photodetector Front-End Dedicated to Real-Time Portable Optical Brain Imaging," Optics and Photonics Journal, Vol. 2 No. 4, 2012, pp. 300-313. doi: 10.4236/opj.2012.24037.

Conflicts of Interest

The authors declare no conflicts of interest.

  
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