A multiple input, multiple output (MIMO) diffiuse optical communications link is implemented and evaluated using a 2 X 2 Alamouti-type, space-time coding scheme to increase link performance beyond that of single input, single output (SISO) and multiple input, single output (MISO) systems. We present a representative profile of received power versus distance, and comparative bit-error probability performance. (c) 2006 Wiley Periodicals, Inc.