Robustness of spatial-coherence multiplexing under receiver misalignment.

It has been shown previously that the spatial coherence of a source can be modulated and demodulated; hence it can be used as the basis for a new dimension of multiplexing in high-speed optical communication links. We address the sensitivity of such a system to misalignments of the receiver with respect to the beam and examine how changing transverse modes affect the spatial coherence in the lateral direction. Specifically, we show that such a system is surprisingly robust for both lateral offsets, in which the receiver is not properly aligned on the beam center, and rotational offsets, in which the receiver is tilted with respect to the plane of the spatial coherence modulation. The presence of higher-order transverse modes or changes in the transverse-mode structure are also shown to have little effect on the system operation.