Analysis of Downlink Satellite Free Space Optical Communications Systems Using State-Space Method for the Rate Equations of the Semiconductor Laser Diode

摘要

Performance analysis of a single carrier satellite optical communication system using laser rate equations by employing state-space technique is carried out in this research. First, a DC analysis is performed in order to determine threshold current and operating region of the semiconductor laser to find a proper quiescent point. Afterward, small-signal characteristics of the laser are derived using a linearized version of the rate equations using the state space technique. Also, Gamma-Gamma distribution is used to model the atmospheric effect of the optical channel. Results demonstrates that the system performance degrades for higher modulation orders, lower bias points and higher zenith angles.