- 80 dBm I pretty low. you wil need to RF amplify the signal BEFORE you use it to drive a laser diode, maybe up to the -10 0r 20 dBm level, in order to keep your signal to noise ratio good.
he RF signal is coupled to the laser diode thru a DC blocking capacitor. The laser diode has DC bias applied so that it is on partially, and the AC coupled RF modulates the intensity up and down. If you put too little RF signal on it, your amplitude modulation of the light is very little % wise.