Monolithic Quantum Dot Mode-Locked Laser for Arbitrary Waveform Generation

In the past, passively mode-locked semiconductor laser sources, which require no synchronization by external driver circuits, were greatly preferred for their simplicity, but were plagued with large timing jitter, > 10 ps that restricted their usefulness as short pulse devices. These passive devices also had limited power output in the pulses due to mode competition above threshold and non-linear gain effects. With the introduction of the quantum dot gain media to semiconductor lasers, the ability to tailor the active region to the passively mode-locked laser cavity and thereby produce a low threshold, low noise condition, has lead to superior performance and to a re-evaluation of the monolithic passively mode-locked semiconductor laser as an ultrashort pulse optical source. The challenges, however, for quantum dot mode-locked lasers are to identify fundamental limitations to the pulse width such as non-linear gain and dispersion and to make the operation more robust. In this Phase I SBIR, we will develop the tools required to move toward optimization of key device parameters. The ultimate goal is to develop the quantum dot mode-locked laser technology to the level where it is useable for an ultrashort pulse optical source for arbitrary waveform generation.