Dark Fiber: No Longer in the Dark
Filed Under: Dark Fiber Info
Written by Joy Milkowski
What could you do with more bandwidth, higher speeds and increased security? Find out for yourself by exploring the benefits of a dark fiber network. Enterprise customers everywhere are turning to a dark fiber solution and gaining performance and control without incurring additional cost.
Dark fiber is optical fiber, dedicated to a single customer, where the customer is responsible for attaching the telecommunications equipment and lasers to "light" the fiber. Traditionally optical fiber networks have been built by carriers where they take on the responsibility of lighting the fiber and provide a managed service to the customer.
In the dot-com bubble, a large number of telephone companies built optical fiber networks, each with the plan of cornering the market in telecommunications by providing a network with sufficient capacity to take all existing and forecast traffic for the entire region served. This was based on the assumption that telecom traffic, particularly data traffic, would continue to grow exponentially for the foreseeable future.
Unfortunately for them, the collapse of the dot-com boom left a flood of fiber, greatly exceeding demand of even the least optimistic forecasts by a factor of up to 30 in many areas. In fact, industry estimates suggest that over 85% of the city-to-city fiber in the United States and Europe has never been utilized or even equipped with networking hardware.
Present day reality is that there are vast numbers of fiber-optic channels in the ground, as of yet, unlit by lasers and network protocol encoders. The availability of wavelength division multiplexing further reduced the demand for fiber by increasing the capacity that could be placed on a single fiber by as much as a factor of 100. IT pros everywhere are keen to cheaper prices, faster speeds, unlimited bandwidth and more control over their networks. For them, dark fiber is a resource that offers high return on their communications investment.
The supply of fiber-optic bandwidth that’s already installed all over the US vastly exceeds demand at today’s prices. One of the basic economic laws suggests that prices decrease when supply exceeds demand. However, this applies when potential buyers recognize the surplus exists and when sellers accept the need to adjust their prices. With an excess supply of dark fiber in many areas, as well as a raised awareness to its existence, companies are starting to see a golden opportunity.
Other advancements are further driving down dark fiber prices, such as CWDM (Course Wavelength Division Multiplexing). CWDM, in contrast to conventional WDM and DWDM, uses increased channel spacing to allow less sophisticated and thus cheaper transceiver designs. CWDM places a relatively small number of channels on a fiber pair, typically four to eight, as compared to DWDM ("D" for dense) technology, which uses a tighter spectral packing (that is, more nearly similar colors of light). DWDM uses 16 to 64 colors per pair.
With few sites exceeding the capacity of eight-channel CWDM on a single fiber pair, today’s abundance of glass in the ground definitely shifts the balance in favor of endpoint simplicity. However, when fiber pairs are scarce, the tighter tolerances of DWDM’s cheek-to-cheek channel packing are cost-effective.
With the help of the late-2003 standardization of CWDM wavelengths, CWDM costs continue to go down. These wavelength agreements give buyers greater flexibility and confidence in the cross functionality of CWDM and DWDM hardware on a single cable plant. For enterprises with growing bandwidth needs, mixed signal freedom makes CWDM a more attractive entry point, as well as an option for expanding established installations.
