Dense Wavelength Division Multiplexing (DWDM) and Fiber Optic Technology.

Essay by BriangUniversity, Master'sA+, September 2003

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Dense Wavelength Division Multiplexing

The increased demands on fiber optic networks toward the end of the twentieth century spurred a concern of fiber exhaust. The backbone communications companies such as AT&T, Sprint, and WorldCom, sought an economical alternative to installing new fiber which resulted in the emergence of a new transmission technology called Dense Wavelength Division Multiplexing (DWDM). The development of this new technology enabled companies to meet the macro capacity demands placed on existing networks by increasing data throughput from 2 Gbps to 40 Gbps and increasable to 200Gbps. This provides a widely scalable solution to companies seeking to alleviate their nearly exhausted fiber networks.

The information services that have permeated our society have become a product that we take for granted. The need for high availability and faster network response times has pushed the telecommunications backbone to its limits. As seen in Figure A, the internet did not become very popular until mid-1999.

These companies chose to implement high capacity SONET networks to alleviate their bandwidth limitations. By using Time Division Multiplexing (TDM), the SONET technology of that time allowed for the transfer of data at bit rates of 2.5 Gbps. Unfortunately, they were unable to foresee the immense augmentation in the data transfer rate in the future (refer to Figure A). While improvements on SONET allowed for the theoretical transfer of 10 Gbps over single-mode fiber, it was "16 times more likely to be affected by chromatic dispersion than" at 2.5Gbps. In addition, these higher bit-rates required transmission power which affected the waveform quality. It was at this time, long haul providers realized that their current TDM system proved to be too expensive and inefficient for national and worldwide (long-haul) data transfers.

Another problem that these backbone providers faced was the emergence of competing carriers. These carriers...