Free Space Optical Communication Through Dynamic Media
Abstract
Free Space Optical (FSO) Communication refers to wireless or unguided propagation of optical signals. FSO systems are used for high rate communication between fixed points over distances up to several kilometers. Despite the major advantages of FSO technology, its widespread use has been hampered by its rather disappointing link reliability particularly in long ranges due to atmospheric turbulence induced fading and sensitivity to weather conditions. The water ‘particles’ that form clouds or fog cause significant loss of received optical power. Even under ideal clear sky conditions, the absolute reliability of a laser communication link through the atmosphere is still physically limited by absorption of atmospheric constituents and the constantly present atmospheric turbulence. Ultrafast lasers provides an opportunity to reconsider laser transmission through dense clouds or fog with a fundamentally different approach: nonlinear propagation in the atmosphere and laser filamentation. A laser filament produces a shock wave that radially expels water droplets out of the beam path and its immediate surrounding. This creates a partially cleared channel significantly larger than the filament diameter, within clouds or fogs to allow unobstructed optical transmission through the atmosphere. The PI proposes to design and develop a hybrid laser system that simultaneously clears a path and transmits optical signals for an unobstructed FSO communication link. The hybrid laser system is composed of a femtosecond laser beam embedded in a donut shaped optical signal. The femtosecond laser pulses create the local cloudless transmission channel for the telecom beam to carry information unobstructed. The information carrying beam will be shaped and modulated using wavefront shaping methods that the PI has developed. This method when implemented, will have a great impact and lead to clear path optical transmission. The proposed study will also develop a method for the characterization of atmospheric turbulence as it impacts optical transmission paths. Further, the results from the study proposed can also be used as a catalyst to research full spectrum detection and characterization of plasma in space.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 28, 2020
- Source ID
- HM04762010012
Entities
People
- Moussa N Gom
Organizations
- National Geospatial-Intelligence Agency
- Rensselaer Polytechnic Institute