Co-Designed Interfaces Between Photonic, Electronic, and Free-Space Domains with Applications for Transmitters and Receivers

Author: ORCID icon
Shen, Xiaochuan, Electrical Engineering - School of Engineering and Applied Science, University of Virginia
Bowers, Steven, EN-Elec & Comp Engr Dept, University of Virginia

In recent decades, the increasing demand for high data rates has been the driving force behind the evolution of communication systems from one generation to the next. In order to meet the requirements for high data transmission, the 5G new radio standard aims to extend the carrier frequency up to 70 GHz in the millimeter-wave (mm-wave) range. The generation of millimeter-wave carriers can be achieved through electronic means or opto-electronic techniques. Compare with electronic systems, opto-electronic systems hold promise and affordability in constructing wideband and long-range mm-wave communication links due to their capability of transporting mm-wave carriers over substantial distances in the optical domain with minimal signal attenuation. Moreover, the advancement of heterogeneous integration techniques enables the realization of compact circuit sizes and high-level integration for opto-electronic systems. Furthermore, heterogeneous integration enables the selection and integration of best-performing devices based on different substrates, thereby enhancing the overall performance of the system. This research presents the generation and locking of mm-wave signals in an opto-electronic approach. Mm-wave carriers up to 220 GHz are generated by the proposed integrated photonically-driven emitters with peak effective isotropic radiated power (EIRP) of 20 dBm through the integration of high-speed photodiode and wideband antenna. Moreover, the generated mm-wave carrier can be locked and cleaned by the proposed optical phase locked loop by heterogeneous integrating a photonic chip with a CMOS chip.
Modern communication standards, such as 5G, not only aim to develop high-speed communication links but also emphasize massive machine-type communications. Internet-of-thing (IoT) devices have gained popularity due to their wide range of applications in areas such as healthcare, agriculture, manufacturing, transportation and smart cities. However, the widespread deployment of IoT devices in outdoor environments presents several challenges including power consumption, sensitivity, and robustness. In order to facilitate long-range communications, it is crucial to achieve high sensitivity. The adoption of event-driven and low-power design approaches becomes essential to extend the battery life of IoT nodes, thereby reducing the cost associated with battery replacements. Furthermore, ensuring robustness against temperature variations, supply fluctuations, and interference is of important to guarantee the normal operation of IoT devices in uncontrolled environments. This research presents an antenna co-designed ultra-low-lower Wake-up receiver (WuRx) that enables event-driven mode for IoT nodes, effectively conserving power. The proposed antenna has a designable output impedance that directly matches the WuRx chip. The co-design between the antenna and the WuRx chip improves system sensitivity and interference robustness, while simultaneously reducing the packaging size by eliminating the need for lossy and bulky matching networks. Additionally, low-power design techniques are implemented to achieve nanowatt-level power consumption. To enhance the robustness against temperature and supply variations, on-chip references are integrated. Collectively, these efforts enable the WuRx to function reliably in uncontrolled environments for extended periods, powered by a single battery.

PHD (Doctor of Philosophy)
photonic integrated circuits, RF integrated circuits, optical phase locked loop, photonically driven emitter, wake-up receiver
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