Systems and methods for using a dispersion compensation circuit to directly modulate a laser. Techniques include calibrating a varactor bias point in a dispersion compensation circuit during manufacturing, but positioning the dispersion compensation circuit between a first attenuator and a second attenuator. Each attenuator, capable of reducing power of an input signal, may be adjustable so that the attenuation provided by each attenuator may be adjusted. The ratio of attenuation between attenuators may be adjusted based on either chirp of a laser or fiber length, and a varactor bias point may be adjusted by the other one of the chirp of the laser or fiber length. Thus, both chirp and fiber length may serve as a basis for adjusting attenuation between attenuators having a dispersion compensation circuit positioned between them.