Laser emitter + receiver for Arduino (Arduino to Arduino communication)
Any idea how high a baud rate we will be able to achieve using the transmitter and receiver?


Looks like the receiver module has a low-pass filter. That could reduce the baud-rate depending on the RC-factor (10 Kohm * 10 nF gives a cut-off frequency of 1.6 kHz). I would recommend checking the actual components. The above is a guesstimate. 

Cheers!