OWC using a monolithically integrated 200 µm APD OEIC in 0.35 µm BiCMOS technology

Area of Science:

• Optoelectronics
• Optical Wireless Communication
• Integrated Circuits

Background:

• Optical wireless communication (OWC) systems require efficient and robust receivers for high-speed data transmission.
• Integrating components like photodiodes and amplifiers onto a single chip can reduce system complexity and cost.
• Achieving reliable indoor OWC necessitates immunity to ambient light and precise alignment with the transmitter.

Purpose of the Study:

• To develop and demonstrate a lens-less receiver for high-speed indoor OWC.
• To integrate an avalanche photodiode (APD) and transimpedance amplifiers (TIAs) monolithically on a BiCMOS chip.
• To evaluate the receiver's performance in terms of data rate, communication distance, receiving angle, and immunity to background light.

Main Methods:

• Fabrication of a receiver chip using 0.35 µm BiCMOS technology, featuring a monolithically integrated avalanche photodiode (APD).
• Integration of four additional PIN photodiodes coupled with differential nonlinear transimpedance amplifiers (TIAs) for beam position sensing.
• Experimental setup for 2 Gb/s OWC testing over a 6.5 m distance with a 22° receiving angle, including controlled background light conditions.

Main Results:

• Successful establishment of a 2 Gb/s indoor OWC link over 6.5 meters with a 22° receiving angle.
• Demonstrated immunity of the lens-less APD receiver to background light up to 6000 lux.
• Effective utilization of the integrated PIN photodiodes and TIAs for accurate centering of the transmitter beam.

Conclusions:

• The developed lens-less receiver with an integrated APD is a viable solution for high-speed indoor OWC systems.
• Monolithic integration in BiCMOS technology offers a pathway to compact, efficient, and cost-effective OWC receivers.
• The system's robustness against ambient light and its beam-centering capability are crucial for practical OWC deployment.