Free-space optical transmission links with unprecedented receiver sensitivity (FREESPACE)

Research Project, 2018 – 2020

Free-space optical communication links provide higher capacity and smaller beam divergence than their radio-frequency counterpart, and are increasingly being used for relatively short links often established for temporary purposes (e.g. outdoor sporting and concert events). They are also explored for extremely long reaches (e.g. between satellites, to the moon and beyond). In both cases, the sensitivity is fundamentally limited by the effect of diffraction, which results in the divergence of a free-space beam as it travels from the transmitter to the receiver. As there are practical limits on the size of the aperture permitted at both the transmitter and receiver, the diffraction results in a signal loss that limits the capacity and reach of the link. Our approach, which is to implement a unique noiseless optical amplifier in the receiver, is expected to result in a 40% transmission reach extension, or for a given reach target, reduce the aperture size of the optics (significant cost reduction) and increase the capacity. Our technique will help enable the transition from radio-frequency links to lightwave based links as it add significant performance benefits to the latter approach. We wish to use our new knowledge and expertise from our recent ERC AdG project to demonstrate, verify, and explore the commercial prospects of FSO transmission using phase-sensitive amplifiers in the receiver to improve the sensitivity, thus maximizing the possible link power budget, beyond what is possible with today’s approaches. We will work on market evaluation, technology verification, and commercialization strategy with the support from the Chalmers innovation office on our campus which has expertize on commercialization in the early stage. A goal of this project is to reach an agreement with commercial and/or institutional entities to pursue a field test of the PSA-based FSO technology.