Coupled-cavity resonant passive mode-locked Ti:sapphire laser

We use a nonlinear quantum-well reflective sample in a coupled-cavity configuration for resonant passive mode locking of a Ti:sapphire laser, producing tunable pulses as short as 2 psec. Pulses of less than 10-psec duration are observed over a 50-nm wavelength tuning range using a single-quantum-well reflector, over approximately 2 mm of external cavity length detuning. Stable mode-locked pulse trains are obtained without active cavity length control; however, the optical spectrum depends on the phase. We generate up to the sixth harmonic of the fundamental repetition rate, at 1.2 GHz, by simply decreasing the external cavity length.