Stabilizing electro-absorption modulators (EAM's) performance by maintaining constant absorption with the use of integrated tap couplers

A tunable electroabsorption modulator (EAM) system, comprising:

• a monolithic stabilized EAM, including;
• a substrate;
• a waveguide layer coupled to the substrate and including;
• an output optical tap section defined by an output tap electrode;
• and
• a modulation section defined by a modulation electrode;
• a semiconductor layer coupled to the waveguide layer;
• a temperature control element coupled to the substrate;
• and
• a temperature sensor coupled to the substrate;
• a tap current monitor electrically coupled to the output tap electrode of the monolithic stabilized EAM to measure the tap current;
• extinction ratio calculation circuitry coupled to the tap current monitor and adapted to determine a bias voltage of the output optical tap section and the modulation section of the monolithic stabilized EAM and an operating temperature of the monolithic stabilized EAM based on the output tap current;
• a bias controller coupled to the extinction ratio calculation circuitry and electrically coupled to the output tap electrode and the modulator electrode of the monolithic stabilized EAM to supply the bias voltage determined by the extinction ratio calculation circuitry to the output optical tap section and the modulation section of the monolithic stabilized EAM;
• and
• a temperature controller coupled to the extinction ratio calculation circuitry and the temperature control element and the temperature sensor of the monolithic stabilized EAM to control the temperature of the monolithic stabilized EAM at the operating temperature determined by the extinction ratio calculation circuitry.