Free space optical communications (FSOC) is a method by which one transmits a modulated beam of light through the atmosphere for broadband applications. Fundamental limitations of FSOC arise from the environment through which light propagates. This work addresses transmitted light beam dispersion (spatial, angular, and temporal dispersion) in FSOC operating as a ground-to-air link when clouds exist along the communications channel. Light signals (photons) transmitted through clouds will interact with the cloud particles. Photon–particle interaction causes dispersion of light signals, which has significant effects on signal attenuation and pulse spread. The correlation between spatial and angular dispersion is investigated as well, which plays an important role on the receiver design. Moreover, the paper indicates that temporal dispersion (pulse spread) and energy loss strongly depend on the aperture size of the receiver, the field-of-view (FOV), and the position of the receiver relative to the optical axis of the transmitter.
© 2008 Optical Society of America
Fiber Optics and Optical Communications
Original Manuscript: January 24, 2008
Revised Manuscript: March 29, 2008
Manuscript Accepted: April 20, 2008
Published: June 4, 2008
Binbin Wu, Zeinab Hajjarian, and Mohsen Kavehrad, "Free space optical communications through clouds: analysis of signal characteristics," Appl. Opt. 47, 3168-3176 (2008)