Pulse code modulation of a gain-switched LD and its application to a high-speed electrooptical time multiplexer

This paper describes the direct pulse code modulation (PCM) method of a gain-switched LD and its application to a high-speed electrooptical time division multiplexer. The method can effectively remove the PCM pattern effect. An experimental modulation is demonstrated at a repetition rate of 1 GHz. Also discussed is a 4 × 1 electrooptical time division multiplexer operating in the multigigabit region. Gain-switched LD´S are used as electrooptic and lower-to-higher-speed conversion devices. The multiplexer is found to be suitable for future high-speed optical communications and optical signal processing.