Improvements in and relating to free-space optical communications

A multi-aperture free-space optical communications receiver comprises a plurality of telescopes each having a clear objective aperture with a diameter between 50 mm and 250 mm and arranged for receiving light collectively from an optical communications light source. A coherent combiner unit is configured for coherently combining the collectively received light to produce a combined optical signal therewith. Each telescope is arranged in association with, respectively, a wavefront detector to determine a wavefront of said received light directed to it by the respective telescope, a steerable reflector unit including a deformable mirror controllable to deform according to said determined wavefront such that said received light is reflected by the deformable mirror with a modified wavefront, and an optical signal receiver comprising a single-mode optical fibre. The steerable reflector unit is steerable to input received light with modified wavefront into the single-mode optical fibre for reception by the optical signal receiver.