Electro-optic system controller and method of operation

An electro-optic drive control system having a preamplifier output coupled to a laser module system input, the laser module system having a laser bias input, a laser output, a temperature sensor output, and a monitoring photodiode sensor output, a method for calibrating the laser module system, comprising:

• connecting testing equipment used for laser calibration to the laser output;
• setting preamplifier gain to nominal;
• connecting input of preamplifier to ground;
• turning off the DC bias for laser;
• canceling the offset voltage of the preamplifier;
• recording the monitoring photodiode dark current;
• incrementing the DC bias to the laser;
• reading PL;
• computing dPL/dIL;
• setting the DC bias to threshold;
• recording PLTH;
• recording the photodiode current IPT;
• recording the temperature of laser module;
• connecting the preamplifier to provide a VREF input signal to the laser module input;
• incrementing preamplifier gain G1 while reading power output PL with instrument;
• determining the preamplifier gain GF needed to obtain full scale output of laser power (PLM);
• determining the corresponding photodiode current for above condition IPM;
• calculating the effective responsivity Reff of the module containing the laser and the photodiode;
• and
• storing the effective module responsivity Reff in memory.