Dynamic Reconfiguration of Differential Pixel Output for CMOS Imager Dedicated to WDM-SDM Indoor Optical Wireless LAN

A dedicated complementary metal-oxide-semiconductor (CMOS) imager with parallel photoreceivers has been deployed for new indoor wireless local area network systems where images and communications are mixed to offer location awareness and an extended data transfer bandwidth with wavelength- and space-division multiplexing for the downlink and uplink, respectively. To realize data acquisition while capturing images, dynamic reconfiguration of differential pixel output with a small area overhead is proposed for suppressing signal contamination at the sensitive photoreceiver circuitry by common mode noise from the image readout digital circuitry. A prototype CMOS imager with 64 times 64 pixels and four parallel photoreceiver channels was fabricated in a standard 0.35-mum CMOS process, and concurrent scene image capturing and multipoint data acquisition at 10-Mb/s/channel were demonstrated. The measured signal-to-crosstalk ratio was around 18 dB.