Coherent WDM technology refers to advanced optical techniques that use modulation of the amplitude and phase of the light, as well as transmission across two polarizations, so that significantly more information can be transported through a fiber optic cable. Using digital signal processing at both the transmitter and receiver, coherent WDM technology delivers cost-effective and highly reliable optical transport in DWDM networks.
When WDM was first introduced in the mid-1990s, the typical wavelength data rate was 2.5G. The move to 10G wavelengths was enabled by high-speed optical modulators and better chromatic dispersion management.
The advent of coherent WDM technology enables 100GbE transport over backbone optical networks and a 10X scaling of network or fiber capacity without any change in DWDM channel spacing or DWDM common equipment design.