Transmitter Aperture Diameter Effect in 40 Gb/s Inter-Satellite Optical Wireless Communication System

Optical wireless communication systems have turned into a state-of-the-art technology because of their superior performance uniqueness and innumerable characteristics, as compared to radio frequency. One optical wireless communication application is Inter-Satellite Optical Wireless Communication. Inter-Satellite Optical Wireless Communication systems can be improved by using, for example, advanced modulation formats and adjusting the aperture diameters. We demonstrate an analysis based on the aperture diameter effect in the transmission of a single channel using a 40 Gb/s Inter-Satellite Optical Wireless Communication system and three different modulation methods, specifically differential phase-shift keying with a duty ratio of 66% or 33% and duobinary. These three modulations were chosen among various modulation formats due to the advantages they provide, i.e., the differential phase-shift keying provides stronger robustness to fiber nonlinearity and duobinary provides higher chromatic dispersion tolerance to mitigate the system requirements for dispersion compensation. The results show the effect of different transmitter aperture diameters (from 2 to 20 cm) at a constant distance (200 km) in terms of the quality factor and minimum Bit Error Rate. We conclude there is a great loss in the small aperture diameter, even in the presence of the best modulation format; therefore, as the aperture diameter increases the Q-factor increases, but some of the increased rise is linear and some changes from linear to non-linear at a fixed Q-factor point equal to 5.63.