Lit Fiber — Metro WDM

Wavelength Division Multiplexing (WDM) optical networking technology transports multiple data streams, protocols and applications over a single pair of fibers. Wavelengths provide end users the flexibility, scalability and security of dark fiber without having to purchase or manage the electronics.

WDM services are great for customers who require multiple circuit types and plenty of room for growth.  Depending on what equipment the carrier uses, the end user can get up to 40 Waves which translates into 40 circuits.  Once the initial circuit is provisioned, the add-on or incremental circuits are very economical.

Wave division multi-plexing offers service in a number of varieties of OCx, 1 gigabit, 2.5 gigabit and 10 Gigabit.   One of the most common applications for WDM services is connecting HQ and datacenter/carrier PoP locations within a metro or datacenter/carrier.  WDM offers reliability, plenty of room for growth, the ability to handle multiple circuit types and an economy of scale for add-on circuits.

While there are several contenders for the protocol and architecture standards (e.g. ATM), what is clear is the need for faster physical layer technology, to 1 Gbps and beyond. One key difficulty is that the most commonly installed fiber in local area networks does not support this bandwidth over distances of 500 meters due to modal dispersion, which limits the effective bandwidth distance product.

WDM offers an attractive solution to increasing LAN bandwidth without disturbing the existing embedded fiber, which populates most buildings and campuses, and continue to be the cable of choice for the near future. By multiplexing several relatively coarsely spaced wavelengths over a single, installed multimode network, the aggregate bandwidth can be increased by the multiplexing factor. The reason behind the use of multichannel optical systems is the amazing bandwidth available in optical fiber. As such, a single high-speed channel takes advantage of an extremely small portion of the available fiber bandwidth.