Multi-element array antennas for free-space optical communication

In this paper we examine the feasibility of using 2-dimensional multiple element array antennas for free-space optical communications. Spatial diversity due to multiple antennas on 2-d arrays can increase aggregate link bandwidth. On the other hand, simultaneous transmissions between the elements on the arrays can cause inter-channel interference, reducing the effective bandwidth. We model this inter-channel interference as noise and find the probability of error due to such noise. Based on this error model, we then derive channel capacity estimations. We present design guidelines based on the link range, number of optical transceivers (elements) that can be packed on a given array, and the achievable aggregate bandwidth.