MEMS control system gain normalization

An optical system comprising:

• a MEMS structure movable between a first position in which light is redirected from a first input port to an output port and a second position in which light is redirected from a second input port to the output port, the first input port spatially separated from the second input port;
• a MEMS actuator for moving the MEMS structure between the first and second positions, and for dithering an orientation of the MEMS structure about the first and second positions;
• a detector optically coupled to the output port for monitoring an intensity of the dithered light and for providing a feedback signal in dependence upon the monitored intensity;
• and
• a controller for receiving the feedback signal from the detector, for determining a control loop gain used in active alignment of the MEMS structure, for applying a first normalization function to the control loop gain, and for applying a second normalization function to a dither magnitude,
• wherein the first normalization function is selected in dependence on the second normalization function,
• wherein the first input port transmits light from a first laser in a laser array, and the second input port transmits light from a second laser in the laser array,
• wherein the output port transmits light into an input waveguide of an optical modulator, and
• wherein the feedback signal is shared between four separate control loops, a first control loop for actively aligning the MEMS structure in a first dimension, a second control loop for actively aligning the MEMS structure in a second other dimension, a third control loop for controlling the bias of the optical modulator, and a fourth control loop for controlling a driver voltage of the optical modulator, the control loop gain corresponding to a gain provided in the first control loop.