Influence of amplified luminescence, recombination nonlinearities and temperature on high-speed modulation and chaotic properties of long-wavelength laser diodes

The high-speed response of long-wavelength laser diodes to harmonic modulation of the injection current has been investigated and modeled. It is shown that intrinsic nonlinearities of gain, recombination processes, and amplified luminescence significantly affect the high-speed laser dynamics. The description of amplified luminescence is based on a space distribution model. Increase in the amplitude of current modulation results in a non-harmonic output response whose form is greatly dependent on the value of the modulation frequency. For a certain frequency region the laser diode output displays harmonic-like response, and the higher the mean current the faster the distortion of harmonic response. It has been shown that temperature increase distorts the modulation characteristics of the lasers. Hence, intrinsic nonlinearities and temperature of long-wavelength laser diodes may create and govern complex regimes of laser dynamics including those used in encoding-decoding laser systems.