Experimental Study on Photodiode Array Sensor Aided MEMS Fine Steering Mirror Control for Laser Communication Platforms

Line-of-sight laser communication application scenarios are numerous including land, mobile, maritime, airborne and space platforms for conventional and tactical utilization. However, beam pointing and stabilization are complicated in dynamic systems such as orbiting satellite to ground receiver, drones, aircrafts and metropolitan free-space optical links vulnerable to natural and artificial disturbances. Small Satellite platforms such as CubeSats are even more challenging due to their limited size and on-board resources. This paper presents an experimental study on a feedback photodiode array sensor assisted control of a one-axis micro-electromechanical (MEMS) fine steering mirror stabilizing a laser communication link on an optical bench in the laboratory. Disturbance profiles similar to vibrations on dynamic platforms are induced into the setup using an electrodynamic vibration machine to test the efficacy of the MEMS fine steering control mechanism. The Photodiode Array (PDA) sensor collocated with an Avalanche Photodiode at the receiving section provides sustained information about the transmitter's movements and beam displacements while the received optical signal strength is continuously monitored. The feedback signals are transmitted to the FSM controller via a radio link. We demonstrate the capacity to stabilize a laser beam transmission in the presence of external disturbances and platform movements using a PDA sensor assisted control.