Beam Pointing Systems
GA-Synopta develops and produces Beam Pointing and Stabilisation Systems that are used, for instance, for laser communications in space and in Optical Ground Stations.
The Coarse Pointing Assemblies (CPAs) cover a hemispherical angular pointing range with very high pointing accuracies; depending on the type of device, the pointing errors can be smaller than 30 µrad at beam diameters of up to 270 mm. The devices are designed for the visual spectral range but are also available optimized for 1’064 nm and/or 1’550 nm. The wavefront quality of the optical beam is hardly affected: the induced wavefront error stays typically below 25 nm rms.
An additional CPA type for space applications supporting smaller beam diameters, the CPA70 is currently in a space qualification program and will be delivered for launch on a low-earth orbit satellite in 2022.
The CPA 270 (for optical beams of up to Ø 270 mm) is designed for ground-based applications under harsh environmental conditions.
The CPA 135 (for optical beams of up to Ø 135 mm) is qualified for space applications and is used today as part of Laser Communication Terminals (LCTs) embarked on geostationary and low-orbiting Earth observation satellites. This CPA type is in series production for space applications.
An additional CPA type for space applications supporting smaller beam diameters (CPA 70) is currently under development.
The Fine Pointing Assemblies (FPAs) for beam stabilisation have a smaller angular range (typically ± 2.5° mechanically) but a very high pointing dynamics (typically 1’000 Hz). Those devices use a two-axes gimballed mirror. The useful beam diameter is about 25 mm, the pointing errors are below 10 µrad. The devices are available for the visual spectral range or can be offered optimized for 1’064 nm and/or 1’550 nm. The induced wavefront error is typically below 15 nm rms.