Performance analysis of a free-space terrestrial optical system in the presence of absorption, scattering, and pointing error

Performance analysis has been carried out to evaluate the performance of a free-space optical terrestrial system using on-off keying in the presence of scattering and absorption due to atmospheric gas molecules and aerosols, and pointing error phenomenon due to the link missalignment. It is found that in order to achieve a bit error rate (BER) of 10(-9) at a visibility of 1.9 km, a 13.2 dB power penalty is incurred for atmospheric channel in haze condition and for atmospheric channel in rain condition, a heavy rainfall rate of 25 mm/h produces a high atmospheric attenuation coefficient alpha, and thus almost 18 dB power penalty is induced to achieve a BER of 10(-9). However, for the atmospheric channel in a fog condition, the visibility can reach 1.1 km and induces a power penalty of 25 dB to maintain the BER of 10(-9). The power penalty increases when the visibility is reduced, rainfall intensity increased, and an additional power penalty of more than 25 dB is incurred in the presence of pointing error for atmospheric channel of 1.3 km visibility in a light fog condition compared to clear weather condition. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3602880]