ABSTRACT
When operators or service providers look to deploy coherent optics into their access networks, they are typically faced with two options: deploy coherent optics on the existing 10G system or build a new coherent-only connection. The ideal network for deploying such coherent systems would be a greenfield deployment on fibers without any compensation devices, such as dispersion compensation modules and other wavelength channels. The commercial coherent 100G transmission systems are showing excellent receiver sensitivity, robustness, and tolerance for channel impairments, such as chromatic dispersion (CD) and polarization mode dispersion (PMD). Full-duplex coherent optics can employ wavelength-division multiplexing (WDM) to support operation with other transceivers simultaneously. Unlike backbone and metropolitan coherent optical networks, access networks don’t require multiple directional optical amplifiers in a cascade optical link. In the case of the hybrid fiber-coaxial (HFC) networks, coherent transceivers may reside in aluminum clamshell enclosures that are network powered.
