Optical Networks

Following the emergence of lasers and optical fibers, optical networking made its beginning in the 1970s with high-speed LANs/MANs. In the 1980s, when the bandwidth of intercity microwave links turned out to be inadequate for digital telephony, the technology for single-wavelength optical communications using SONET/SDH arrived as a saviour to replace the microwave links. However, single-wavelength links couldn't utilize the huge bandwidth (25 THz) of optical fibers, while the bandwidth dema...