High Speed Electronic Wavefront Error Correction for Free-Space Optical Systems

Abstract

Researchers at UCF have developed a new solution that replaces the slow and costly deformable mirror loop with a detector array and digital signal processing (DSP) chip. Free-space optical communication has become an alternative to fiber-based technologies and is implemented when physical connectivity is impractical (for example, satellite communication).

Unfortunately, transmission of light through the atmosphere induces devastating wavefront distortions that ruin the signal's content. Therefore, the inclusion of signal corrective technologies is required. Currently, adaptive optics techniques are used to perform this correction, and consist of feedback loops with deformable mirrors that sample and iteratively correct the signal. While this technology has allowed free-space communication to become successful, physical correction of the optical signal is both costly and slow.

Technical Details
The invention samples an incoming signal (whether for communication or imaging) through a detector array that references against a local oscillator source generating an interference pattern from which the atmospheric wavefront distortion is calculated. These readings are subtracted from the incoming signal as a correction. Performance of this technique approaches a system free of wavefront distortion and could be used to greatly increase the capabilities of any system that suffers from random media wavefront distortion.

Benefit

Market Application

Publications

Electronic wavefront correction for PSK free-space optical communications, Electronics Letters, Vol. 43, Issue 20,  (27 Sept. 2007): 1108-1109.