Overcoming Resolution and Bandwidth limIT in radio-frequency Signal digitisation (ORBITS)

Analogue-to-digital converters (ADCs) are the essential links between physical world in which all signals are 'analogue' (e.g., electric current generated by a microphone or a picture captured by a mobile phone camera) and the digital world of '0s' and '1s', where we store, transmit and process signals and information. ADCs enable (digital) computers to process signals from the (analogue) physical world. This capability has revolutionised our entire society, making computers (desk-tops, lap-tops, or smartphones) ubiquitous. In recent years, we have witnessed a dramatic increase of the amount of information that is generated, stored, transmitted, and processed, driven by increased demand of our society on data and information and newly emerging applications such as virtual and augmented reality. All this information needs to be processed by ADCs, which can address the abovementioned need only when performing with better accuracy, affordable power consumption, in real-time (with low latency), and for increasingly broader bandwidth (faster) signals. This is extremely challenging with currently-existing technologies and is being vigorously pursued by both academia and industry. Most of these approaches are based on strategies like the use of application-specific integrated circuits (ASICs), photonic time stretch, or time interleaving. Unfortunately, all of these approaches seem to have formidable challenges. A clearly realisable route to next-generation ADCs that could support information growth in the next decade and beyond is currently lacking.

ORBITS aims to provide a radically novel and future-growth-proof solution to ADCs using optical assisted means. Specifically, it will exploit unique features of recently-emerged optical and photonics technologies, including optical frequency combs, coherent optical processing, and precise optical phase control. Optics offers three orders of magnitude larger bandwidth than microwave electronics used for ADCs today and has the advantages of ultrafast (femtosecond level) responses. The optical frequency comb technologies, in conjunction with coherent optical processing and phase control, enables dividing signal with high accuracy in the optical domain, which overcomes the fundamental limits such as timing jitter (time uncertainty) in conventional approaches, opening up a scalable and integratable technology for large bandwidth high resolution ADCs.

For practical (low-cost when volume-manufactured, compact, and low-power-consuming) implementation, ORBITS will investigate optical and electronic integration, which permit to harness merits across different photonics integration platforms, through collaborations and open foundries. Besides next-generation ADCs, ORBITS will study applications in future-proof high capacity optical and wireless communications. It assembles complementary expertise from top research groups in Universities and companies, aiming for a wide academic impact and a straightforward knowledge transfer to industry.