Coherent WDM technology offers higher bit-rates, greater degrees of flexibility, simpler DWDM line systems, and better optical performance.
Simplify Your DWDM Network
Coherent WDM technology helps streamline DWDM network planning and deployment, thanks to soft-decision Forward Error Correction (FEC), a method of encoding the original signal with additional error detection and correction overhead information to detect and correct errors that occur in the transmission path.
FEC provides more margin, allowing higher bit-rate signals to go farther distances with fewer regenerator points. This results in simpler photonic lines, less equipment, lower costs, as well as a significantly larger bandwidth in a DWDM network.
Maximize Fiber Capacity
Spectral shaping is also a common technique of coherent WDM technology when deploying a DWDM network. It is a way of applying dynamics processing across the frequency spectrum. Thus it can help bring balance to the sound of instruments and voices in a way that traditional compressors and equalizers have not been able to in the past.
Spectral shaping provides greater capacity across cascaded Reconfigurable Optical Add-Drop Multiplexers (ROADMs), enabling increased spectral efficiency for DWDM channels. As a critical technique in flexible WDM grid systems, it allows carriers to be squeezed closer together to maximize capacity.
Coherent WDM technology can be tailor-made for a wide variety of DWDM networks and DWDM applications. Coherent optical line cards can support multiple modulation formats and different baud rates, enabling operators to choose from a variety of line rates. Fully programmable coherent WDM transceivers provide a wide range of tunability options with fine granularity between incremental capacities. Network operators can make use of all available capacity and convert excess margin into revenue-generating services.
Strong Mitigation to Dispersion
When optical signals are transmitted across a fiber cable, there are inevitably fiber impairments such as chromatic dispersion (CD) and polarization mode dispersion (PMD). By mitigating dispersion effects, the advanced digital signal processors (DSPs) in coherent WDM technology take away the headaches of planning dispersion maps and budgeting for PMD. This also removes the cost and latency of dispersion compensation modules (DCMs).
In addition, coherent processors improve tolerances for Polarization-Dependent Loss (PDL) and track the State of Polarization (SOP) to avoid bit-errors due to cycle slips that would otherwise affect optical performance. As a result, operators can deploy line rates up to 400G per carrier across longer distances than ever. High bit-rate signals can even be deployed on old fiber that previously couldn’t support 10G.