Theory and experiment of the parasitic-free frequency response measurement technique using facet-pumped optical modulation in semiconductor diode lasers

Abstract

The letter describes the theory and experiment of the newly developed parasitic-free frequency response measurement technique using facet-pumped optical modulation on diode lasers. It was found that the modulation damping rate depends on the relative position of the pump laser wavelength with respect to the Fabry–Perot resonance wavelength of the laser under study. This effect is fully explained in terms of the carrier-induced index change. For multilongitudinal mode lasers, it is shown experimentally and theoretically that the damping rate and frequency response measured by this technique give the intrinsic frequency response corresponding to direct current modulation only if the cavity lengths of pump and probed lasers are equal, and then only if the pump laser wavelength coincides with the Fabry–Perot transmission maximum or minimum of the probed laser.