A robust 2×2 CMOS receiver array for meter-scale point-to-point OOK VLC links

This paper presents a fully integrated 2×2 optical receiver array for Point-to-Point (P2P) On-Off-Keying (OOK) visible-light communication (VLC) links. The 2×2 PD-array design constraints and cross-talk issues are discussed. Each receiver exhibits a low input referred noise density of 5 pA/VHz to meet the sensitivity requirements of free-space optical wireless links in the visible spectrum. The VLC receiver is tested as a part of an optical setup at 2.7 m and 6.7 m distances from a 680-nm laser-diode source. A measured 2.3 Gb/s per-channel data-rate with a VLC-compliant bit-error-rate is achieved through the use of high bandwidth circuit design techniques and a programmable integrated equalizer function. The receiver is implemented in AMS 0.35 μm technology. Each single receiver draws 65 mA from a 3.3 V DC voltage supply. The complete array size is 2.0 mm × 1.6 mm.