Patent attributes
The present invention provides a software-based electro-optic modulator bias control system resident in an optical transceiver including an electro-optic modulator that includes an optical-to-electrical converter including a transimpedance amplifier, an analog-to-digital converter, and a software algorithm, wherein the software algorithm is operable for determining an optimum bias voltage applied to the electro-optic modulator by discovering a maximum average optical power transmitted by the electro-optic modulator, or quadrature point, wherein the quadrature point is discovered by determining at what bias voltage the slope of an average optical power transmitted by the electro-optic modulator, defined as an optical power change given an incremental bias voltage change, is equal to zero. The software-based electro-optic modulator bias control system also includes a control loop operable for determining if a radio frequency port of the electro-optic modulator is driven to a peak-to-peak voltage that is greater than (over-driven) or less than (under-driven) the peak-to-trough voltage of a response curve of the electro-optic modulator.
