Collaborative Research: 3D Integrated Imaging Receivers for 10-Gb/s Free Space Optical MIMO

Tufts University, Medford MA

Investigators

Abstract

The objective of this research is to create a new class of power-efficient imaging photoreceivers to reach an aggregated data rate of 50 gigabits per second and beyond for broadband wireless optical communication. The approach is to develop a large array of planar tessellated photodetectors with a rate of 10 gigabits per second per pixel. The array includes diversity selection circuits, which are implemented using an optical multi-input/multi-output configuration. With respect to intellectual merit, this project addresses two well-known challenges in optical wireless communication, channel scintillation and optical beam alignment. The research explores power-efficient InGaAs metal-semiconductor-metal photodetectors that are integrated with silicon integrated circuits for multifunctional operation (decision, amplification, and computing), and the implementation of multi-input/multi-output architectures for signal processing of massive amounts of data. This research is expected to augment the body of knowledge on carrier drift characteristics in the photodetectors at low voltage bias and the physics of complex three-dimensional optoelectronic device structures. This research also explores heterogeneous integration of compound semiconductor device on silicon circuits using three-dimensional wafer bonding for photoreceiver applications. With respect to broader impacts, the research has the potential to benefit a variety of applications, including wireless networks with reduced security vulnerabilities, networks able to transfer high-resolution digital images in the midst of equipment sensitive to electromagnetic interference in healthcare settings; and optical interconnects in large-scale data centers. A cross-university curriculum is addressed, covering multi-disciplinary topics in information theory, system-level design, analog circuits, device physics, fabrication and integration. Various programs are used to recruit students from underrepresented groups. K-12 outreach efforts are coordinated through the Tufts Center for Engineering Educational Outreach.