Lasers on Kris's ships

Kris got this question from someone with a hotmail account that we couldn't reply to because of some sort of security thing.

"I've found references to Pulse Lasers, Burst Lasers, and some form of Laser referred to as a "long pop gun" in the various books. What are the differences between the various forms of laser other then pulse lasers usually being a lot bigger then the other. (14 to 24 inch pulse lasers with the others usually around 5 or 6 inches.) Also how do Pulse Lasers work? Mutineer ...