Hello NITHIN
Welcome to optisystem forum,Since you are working on OWC i would recommend you to read the paper i have attached,beacause these paper consists of the work on OWC link using MIMO,Multiple Tx Rx and DWDM ISOWC.
http://www.ijert.org/view-pdf/287/performance-improvement-of-intersatellite-optical-wireless-communication-with-multiple-transmitter-and-receivers
http://www.ripublication.com/aeee/027%20%20pp%20%20847-852.pdf
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6400458&filter%3DAND%28p_IS_Number%3A6400452%29
https://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB8QFjAA&url=http%3A%2F%2Fwww.scipublish.com%2Fjournals%2FSTSP%2Fpapers%2Fdownload%2F3309-1062.pdf&ei=zX2LVYmNKcnJuATLq4OQDw&usg=AFQjCNHxw81HxLUzi9alLClVb4AGBq9UjA&sig2=6WlWHAujQSlax-C2emmrmw&bvm=bv.96782255,d.c2E
Regards