Pretty sure only his attorneys would have access to that info, not him, though generally defendants have a legal right to all of their attorney's notes/discovery. I'd bet there's a restraining order that prevents him from contacting any witnesses, though, and all calls and mail in and out of prisons is monitored and recorded.
Messed up as it is for the victim, part of the trial process includes the defendant having the right to confront any accuser, and that can include witnesses who identify them in certain instances.