DWDM, or Dense Wavelength Division Multiplexing, has been a key technology evolution, as it allows multiple signals to run over a single strand of fibre, thus dramatically increasing the bandwidth potential of an individual network link.
Today, multiple high-bandwidth services running at 10Gb/s, 40 Gb/s, and 100 Gb/s can be multiplexed onto a wavelength, and delivered over a single strand of fibre. Dark fibre networks represent an excellent way to ensure future capacity demands can be met.
Without DWDM most of the Web 2.0 and cloud-computing solutions in use today would not be possible.