Semiconductor light sources for 40-Gb/s transmission systems

The status and prospects of semiconductor light sources for 40-Gb/s transmission systems are reviewed in regard to the following three topics: direct modulation, external modulation, and pulse sources for return-to-zero format. Included are discussions on direct modulation of a 1.3-/spl mu/m distributed feedback laser for 40-Gb/s very-short-reach optical links, progress made in developing external modulators based on electroabsorption of multiple quantum wells, and mode-locked lasers for carrier-suppressed return-to-zero modulation format.