A system and method for calibrating laser designator and rangefinder test sets. The system includes a high speed detector module which receives a laser input signal, and outputs a laser output signal and an electrical pulse shaped output. A variable attenuator module receives the laser output signal and includes a rotating waveplate which rotates a polarization of the received laser output signal and a Glan laser polarizing beam splitter which receives the rotated laser output signal. The polarizing beam splitter passes only vertically polarized portions of the rotated laser output signal. An energy detector module receives the vertically polarized portions of the rotated laser output signal and includes a beam splitter which splits the vertically polarized portions of the rotated laser output signal into a first path pulse and a second path pulse. The second path pulse and the electrical pulse shaped output are used to calibrate a laser designator/rangefinder test set.