Liquid Lenses for Aerospace Beam Steering and Communications: MOSAIC

Laser communications (lasercom) can enable more efficient and higher bandwidth communications than conventional radio frequency (RF) systems, but requires more sophisticated pointing and tracking (PAT) systems to acquire and maintain links. Liquid lens arrays can provide compact, nonmechanical beam steering as an alternative to fast-steering mirrors and mechanical gimbals. An array of two liquid lenses offset in perpendicular axes along with a third on-axis lens in the array are used for beam steering and divergence control, respectively. The Miniature Optical Steered Antenna for Intersatellite Communications (MOSAIC) project applies liquid lens technology to create a transceiver for laser communications on spacecraft to enable wide field-of-view communications. This work provides analytical models of beam steering in order to inform subsystem sizing, and uses simulation studies along with previous work on space environment evaluation of liquid lenses to produce representative link budgets for a liquid lens based lasercom transceiver. A 25 Mbps link with 4 W transmit power at 1550 nm (optical C band) and 16-ary pulse position modulation (16-PPM) can be maintained up to 300 km separation with 3 dB margin, using larger pressure-actuated liquid lenses from Optotune arranged for hemispherical steering.