EFFECTS OF CARRIER-INDUCED MODAL INTERMODULATION ON DYNAMIC SPECTRAL CHARACTERISTICS OF MULTIMODE FABRY-PEROT LASERS

The physical mechanism attributed to producing 'rabbit-ears' on the ch irped multimode optical spectra of gain-switched Fabry-Perot semicondu ctor lasers is investigated thoroughly. It has been observed experimen tally that the short-wavelength rabbit-ears are dominant in the short- wavelength longitudinal modes. However, the long-wavelength rabbit-ear s are dominant in the modes near the lasing wavelength, while the shor t-wavelength rabbit-ears are again dominant in the longest-wavelength modes. In this paper, the unequal rabbit-ears of each mode and the asy mmetric chirped spectrum are shown to be a result of the dynamic power transfer between the modes during the gain-switched optical pulse due to carrier-induced modal intermodulation. Such an understanding, and the ability to model accurately this characteristic, is also shown to be essential for designing Fabry-Perot laser systems, for short-haul a pplications such as fibre-to-the-home.