Photonics-Driven Sub-Millimeter Interconnect

The skyrocketing demand for data traffic and machine-to-machine communications will lead to an overwhelming global data volume of 200 Zettabytes within the next years. The information factories, as host for the vast computational powers that enable many of today’s applications, demand already more than 20 nuclear power plants to satisfy their thirst for energy. Unsurprisingly, this consumption shows an alarmingly strong tendency to increase in near future and is likely to reach a high share of more than 20% in global CO2 emissions by the end of the decade. However, there is a key enabling technology which offers a solution: Photonics stands for high throughput in various ICT applications, which is paired with an outstanding energy efficiency. Towards this direction, industry and academia have been working on promising opto-electronic approaches over the past decade. Nonetheless, copper-based solutions have remained dominant in various very-short reach segments, such as server backplanes or on-board communications, as cost is still the driving factor.

Delivering data rates of up to


fronthauled optically at


and carriered through RF at more than


PHIDELITI aims to eliminate power-hungry copper in very-short reach communications. As a multi-disciplinary project that spans over the key enablers photonics and microelectronics, it proposes to tackle this challenge through blending opto-electronics and sub-millimeter wave communications. By doing so, it will reap the best performance of both worlds: high energy efficiency over longer reach, and low cost over very short reach, while addressing its mission to place the high-speed data interface closer to the processor – without facing an energy and performance brick wall as it applies to copper.

Driven by and capitalizing on its innovative SiGe integrated circuit technology, PHIDELITI will develop hybrid coherent optical/sub-millimeter circuits with high functional density, including high-bandwidth transimpedance amplifiers and modulator drivers for 25 GHz per-lane rates, sub-millimeter wave modems and power / low-noise amplifiers operating at 145 GHz, which are paired with an analogue coherent homodyne transceiver engine realized in heterogeneous SiGe-BiCMOS/InP technology.

System-wise, the low-complexity coherent optical feed, together with high-speed sub-millimeter wave data delivery over polymer rather than copper waveguides, using carrier frequencies beyond 100 GHz and broadband modulation without the need for equalization or digital signal processing, will not only reduce the costly chip real-estate required to realize all functions, but will also lead to an energy efficiency that outpaces that of copper-based solutions by a factor of 12. At the same time, the use of SiGe technology, which is considered a sweet spot for high speed applications combining radio frequency performance with low cost, will ensure that the required cost credentials are met to ultimately eliminate copper-based wired communications in very-short reach links.

Given the imperative for speed, PHIDELITI will evaluate its technology under the challenging datacom scenario with up to 100 Gb/s per-lane data rates on printed circuit boards for server backplanes, but will also investigate the power of its technology in consumer-oriented setting such as in-vehicle networks.