Intracavity spectral shaping in external cavity mode-locked semiconductor diode lasers

Intracavity spectral shaping techniques have been employed to artificially shape and broaden the optical spectrum of external cavity mode-locked semiconductor lasers. Using an intracavity spectrometer and intensity Fourier-plane filtering, active mode-locked output spectra with a multiplicity of independently tunable wavelengths have been generated, while an adjustable intracavity etalon has been employed to generate an 18-nm spectral width. Furthermore, hybrid mode-locking with a multiple-quantum-well (MQW) saturable absorber combined with the intracavity etalon, followed by dispersion compensation has led to the generation of optical pulses of 330 fs in duration.