A Linear Closed Loop Feedback System for Beam Wander Correction in Medium-Range Optical Link

Free Space Optical Communication (FSOC) is gaining popularity as a viable solution in various applications due to the advantages it offers in terms of bandwidth, EMI immunity, security, cost and deployment time. Being a Line-of-Sight (LoS) technology, it is of utmost importance that the alignment between the transmitter and the receiver is maintained. After the optical link is attained, the laser beam displacement due to the beam wander has to be mitigated. A laser beam stabilisation system, employing a Fast Steering Mirror (FSM), a position sensor and a controller to form a linear closed loop feedback system to correct the positional error in real time is presented in this paper.