Patent ID: 6909731

Claim:
An automatic power control system for simultaneously adjusting an output power and an extinction ration of a laser diode comprising: a bias current determination unit including: a first difference determination unit for determining an average power difference between a current measurement of an output power of the laser diode and a reference average output power, and a first integrator communicatively coupled to receive the determined average power difference from the first difference determination unit, the first integrator summing the determined average power difference with a determined average power difference based on at least one previous measurement by the first difference determination unit resulting in a bias current output signal; and a modulation current determination unit including: a nonlinear processing block for determining an absolute value of the current measurement adjusted by a nonlinear estimation reference constant, a second difference determination unit communicatively coupled to the nonlinear processing block for determining a power variance difference between the determined absolute value and a reference power output variance proportional to an extinction ratio P 1 /P 0 for reference power levels P 1 and P 0 wherein P 1 represents a digital one value and P 0 represents a digital zero value, and a second integrator, communicatively coupled to receive the determined power variance difference from the second difference determination unit, the second integrator summing the determined power variance difference with a determined power variance difference based on at least one previous measurement by the second difference determination unit resulting in a modulation current output signal.