Characterization of C-band laser transmitter through atmosphere in littoral environment

Abstract

Optical link prediction capabilities are important for planning and operating a free-space, optical communication link outdoors. The impact of the atmospheric channel on the optical link is dependent on factors like geographic location and local atmospheric conditions. Currently, link predication and analysis tools, like the Navy Atmospheric Vertical Surface Layer Model (NAVSLAM) and the Path Characterization System (PCS), are used to predict the atmospheric characteristics and received power. Additionally, the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) is a model that has recently been integrated into PCS and needs to have its prediction of refractive index structure parameter (Cn2) validated from outdoor range data. The bit error rate is a measure of error probability and when combined with baud rate, can be used to predicted the data transmission rate. In this experiment, the characterization of a one-way laser communication link was conducted outdoors on a 1 km range in a littoral environment. During communication, the bit error rate and received power were measured on the receiver side of the link. Additionally, the local atmospheric conditions were measured and utilized by link analysis tools, including the NAVSLaM, COAMPS, and PCS. These tools have been used to quantify the turbulence and path losses and evaluated against range measurements. The bit error rate and received power were also computed and compared with the measurements on the range to evaluate link predictive capabilities.