Demonstration of phase correlation in multiwavelength mode-locked semiconductor diode lasers

Wideband spectral phase correlation is demonstrated from a multiwavelength mode-locked semiconductor laser. By use of frequency-resolved optical gatin g techniques, significant phase correlation was observed between multiple i ntracavity oscillating wavelengths, with wavelength separations of similar to 1 nm. The resultant temporal characteristics show a substantial modulati on owing to the spectral coupling induced by intracavity-generated four-wav e mixing. This result may lead to novel methods for directly generating ult rafast subpicosecond optical pulse sequences with spectrally tailored ampli tude and phase characteristics from actively mode-locked semiconductor lase rs. (C) 1999 Optical Society of America. OCIS codes: 140.4050, 140.5960, 19 0.4380, 250.5980, 320.7120.