OTDM: Present and Future Prospects

With the ever-increasing demand for higher speeds and larger capacity brought about by rapid data growth on the Internet, interest in optical time division multiplexing has been growing rapidly in recent years due to its high speed and ability to overcome the “electronic bottleneck” offered by today’s electronic components. In contrast to WDM where multiplexing occurs in the frequency domain, OTDM transmits multiple data channels in the form of ultra-short duration optical pulses which are interleaved into a single high-speed data stream by accurate control of their relative delay in the time domain. At the receiving end, an optical gate is used to extract one base rate tributary from the aggregate data stream for subsequent processing. The operating principle of OTDM is illustrated in Fig .2.1.