Programmable Microwave Photonic Signal Processors

The world today is connected by fiber-optic communication links and wireless RF connections. Both communication paradigms operate in a distinct domain, but as our communication infrastructure expands, the conversion between these domains becomes increasingly costly, because it requires not only electro-optic conversions and back, but also expensive conversion between the analog and digital signal domain. As bandwidth and datarates increase, RF electronics becomes more power-hungry, and the concept of processing signals in the optical domain becomes more attractive.

In this PhD project we want to explore the capabilities of programmable or configurable photonic chips for so-called microwave photonic applications. In microwave photonics, high-speed RF signals are converted into the optical domain, where they can be amplified, filters or converted between frequency bands. This can be done on the surface of a photonic chip. By adding electronic tuning and monitoring capabilities to these photonic chips, the functions can be configured and multiple functions can be combined, making these circuits more versatile. For microwave photonics, such circuits could combine widely tunable filters (tunable passband and frequency over > 1 decade), true-time-delay for beamsteering, and frequency conversion. IMEC is a leader in this field of complex photonic chips and microwave functions.

Starting from existing configurable and programmable photonic chips made in IMEC, the research will explore the capabilities of these chips for microwave signal processing. This will also expose the limitations, and the need for improved driver electronics and packaging. That is why this PhD is a collaboration between two IMEC labs in Ghent: The Photonics Research Group and IDlab, each bringing in their respective expertise in photonics and high-speed electronics.

The programmability of these photonic chips should make them useful for a variety of use cases: there are many possible applications for microwave photonics: wireless communications, sensing, radar, … One of the goa2025ls is to assess where these chips can add value, and where their limitations are. This can then lead to next-generation designs (that will be fabricated and tested) to address these limitations. For instance, standard programmable photonics might not provide a sufficiently granular set of delays for microwave beam steering, and a chip design with fractional delays could overcome this.

This project will comprise a combination of design and simulation, basic fabrication and packaging, and testing the chip performance both in the optical and the microwave domain.