Evaluation of Aperture Diameter Variation on OFDM Inter–Satellite Optical Wireless Communication (Is–OWC)

Inter-satellite optical wireless communication (Is–OWC) is an inter-satellite communication system that uses a light source originating from a laser. This system increases the bandwidth and transmits data with high bit rates. Is-OWC communication uses a lens to focus light from transmitter to receiver. Therefore, the optical lens aperture diameter and the operated wavelength of the optical source may affect the performance of the long-distance communication system between satellites. The coherent optical orthogonal frequency division multiplexing (CO-OFDM) system is also used to minimize multipath fading effects during long-distance transmission and increase receiver sensitivity. The proposed research investigates the effect of the aperture diameter and operating wavelength on the performance of the Is-OWC system using OFDM and coherent detection techniques. The simulation results show that the received power using 850 nm is higher than that of using 1550 nm where the gain increases as an increase in the aperture diameter. At a distance of 1,500 km, using 850 nm can achieve the received power of more than −36 dBm and maximum −23 dBm for an aperture diameter of 10 and 30 cm, respectively. Regarding the detector sensitivity of −33 dBm, the maximum LEO transmission distance of 3,500 km satisfies the requirements using an aperture diameter of 20 to 25 cm. Meanwhile, MEO transmission in the range of 4,500 km can only be achieved using an aperture diameter of 30 cm.