What is the "external power supply" used for?

The "external power supply" is a DC power supply provided by the user; it is connected (via banana plugs) to the pulse driver LDD100 and is delivering the electrical power feeding the laser. Any standard laboratory power supply can be used, as long as it is ripple-free ($\leq$1%), voltage regulated, with variable voltage from 0V to at least 35V, and capable of delivering 1A DC for duty cycles up to 2%. For higher duty cycles, contact Alpes Lasers SA, since not all lasers are capable of working at more than 2%.