The LaserKraftwerk is obtained in the London Nautica during the Resistance's attack to get Prototype Stealth Helicopters. It can be upgraded as follows.

Strobe: When firing, a blinding light flashes and temporarily disorients nearby targets.
Tesla: Alters the beam's frequency to affect mechanical targets close to its path.
Targeting Scope: Allows it to track, target and fire at several enemies simultaneously at the cost of depleting its battery power.
Generator: Slowly regenerates battery power. Obtained in the Da'at Yichud vault.
Reflector: Laser beams can reflect off a surface, but do less damage.
Automatic: Allows full-automatic firing.
Final upgrade: Increases ammunition capacity by 25 rounds.