Light in the Bucket (RET Project)

In modern communication systems, fast data transmission sometimes is achieved through free space optically. So-called point-to-point laser communication systems use directed laser beams to encode and receive information. The free-space atmosphere the transmission has turbulent variations of refractive index, aberrating the beam and reducing data rates. Adaptive optics uses a wavefront measurement device and a correction device (a deformable mirror) to compensate for aberrations through closed loop control. BU is a world leader in making and controlling deformable mirrors.

The project involves making a physical system that can simulate atmospheric aberrations. The RET will design, build and test a system that can produce aberrations with the temporal and spatial characteristics of real atmospheric turbulence. One approach could be to develop a spinning transparent disk that has, on its surface, topography variations comparable to those encountered in outdoor horizontal beam paths. But the design could take many different forms. Ultimately, the performance of the simulated control system will be measured by the strength of the laser beam arriving at the receiver, which is called “Light in the bucket.”