Analysis of Internal Design Parameters to Minimize Geometrical Losses in Free-Space Optical Communication Link

During the last two decades, free-space optical links got considerable importance due to their benefits of higher data rates, license free-spectrum, easy and rapid deployment and mobility. Free-space optical links use carrier frequency in the range of 20 THz to 375 THz (in near infrared (IR) region and visible band in wavelengths) to establish a communication link for terrestrial communication, inter-satellite links, deep space links, ground-to-satellite and satellite-to-ground links. Free-space optical links are also useful for different military applications, disaster recovery and last mile access. However, despite of having all these advantages the performance of free-space optical links depends upon the atmospheric conditions and parameters of system design. Geometrical losses of free-space optical links are directly related to parameters of system design or internal parameters. In this paper we analyzed different parameters of system design to minimize the geometrical losses. We presented the analysis of internal design parameters like divergence angle, diameter of receiver aperture, diameter of transmitter aperture, link distance and suggested the suitable parameters of system design.