Abstract

Long-wavelength MQW lasers have achieved modulation bandwidths for of 25 GHz for Fabry-Perot devices and 22.5 GHz for DFBs.^1,2 These results are achieved by increasing the intrinsic frequency response of the laser diodes through an increase in the differential gain. The differential gain increase can also lead to reduced wavelength chirping, from a reduction in the linewidth enhancement factor. In this work we have carried out extensive characterization of below threshold gain spectra of the Fabry-Perot lasers in ref. 1, coupled with measurements to calculate carrier density versus bias current. These measurements then provide contours of gain and differential gain versus wavelength and carrier density, which allow device optimization for high speed or low chirp. Resonance measurements on the same devices are used to calculate an independent value of differential gain to verify the gain measurements.

© 1994 Optical Society of America