PIN Photodiode Optoelectronic Integrated Receiver Used for 3-Gb/s Free-Space Optical Communication

In this paper, an optoelectronic integrated receiver chip including five PIN photodiodes will be presented. A large 200-μm diameter photodiode connected to a high-speed transimpedance amplifier works as a 3-Gb/s receiver for optical wireless communication. Four surrounding photodiodes allow for the adjustment of the incoming laser ray. The complete chip was realized in a silicon 0.35-μm BiCMOS technology to benefit from the available intrinsic zone in this technology. Due to this intrinsic zone and an antireflection coating, the responsivity reaches a value of more than 0.5 A/W for wavelengths from 630 to 760 nm. Furthermore, the capacitance of the center photodiode is less than 0.6 pF for reverse bias voltages larger than 3 V. For proof of concept, a steerable and adjustable light source was built based on a micro-electro-mechanical system mirror, on a focusing unit, and on a direct modulated vertical cavity surface emitting laser with a wavelength of 680 nm. The complete system is capable of establishing a 3-Gb/s data transfer over a distance of 19 m at a BER of <;10^-9, and over a distance of 18 m at a BER of <;10^-12.