METHOD FOR DRIVING A SEMICONDUCTOR LIGHT SOURCE DEVICE FOR TRANSMITTING A SIGNAL WHILE SUPPRESSING DYNAMIC WAVELENGTH VARIATION DURING FAST MODULATIONS, SEMICONDUCTOR LIGHT SOURCE DEVICE, AND OPTICAL COMMUNICATION METHOD AND SYSTEM USING THE SAME

摘要

In a driving method or apparatus for driving a semiconductor laser as a light source for optical transmission, oscillation light of the semiconductor laser can be switched between two different polarization modes by modulating a current injected into a portion of a waveguide of the laser. The laser has characteristics that light in both modes is emitted within a polarization-mode switching range of the current and that intensities of the light in both modes respectively vary in accordance with an amount of the current within the polarization-mode switching range. The current injected into the portion of the waveguide is urged to a bias point current in the switching range, and a modulation signal current is superimposed on the bias point current such that the emitted light in at least one of the modes is intensity-modulated in accordance of an amount of the modulation signal current.