Laser pointer types are not really very good as laser diodes which emit visible light are generally much slower than IR types and cannot be modulated very quickly.Mind you having designed a similar system using ordinary IR diodes rather than laser types,themain problem is that the reciever amplifier needs to be very carefully designed.There are a lot a gottchas for sounds like a simple design problem.The maths for calculating bit error rates for a given reciever sensitivity and noise figure is very nasty.
Jez