Stability evaluation of a ridge-integrated laser modulator based on a butt-coupling approach

Ridge integrated laser modulator (ILM) devices were fabricated using a butt-coupling technology based on two-gas-source molecular-beam epitaxy. A complete stability evaluation was undertaken, including a reliability study on discrete lasers, discrete modulators, and integrated devices. High temperature, high current, and high voltage were applied for over 1900 h without significant evolution of the electrooptical characteristics. A functional aging test at the current corresponding to a 2-mW output power and the modulator bias necessary to reach the maximum extinction ratio was performed for more than 1500 h. The butt-coupling region does not affect the reliability of the integrated devices.