The optical power regulator is a module that maintains a constant output power, regardless of the input fluctuations. This is achieved by using a detector to tap a small amount of light from the output and feed into a close-loop circuit to control a MEMS variable fiber optical attenuator connected between light input and output. The regulation output power range is set by the two pots on the board and can be preset according to customer spec. The module can also compensate slow polarization dependent loss changes and fast optical power surges. The optical power regulator provides an ultimate solution for optical power stabilizing and limiting. device is designed for over 20 years continuous operation. The unit comes with a wall-plug 12V power supply.