Optical Services over Middle-Mile Networks

Many carriers and last-mile providers may be interested in purchasing out-of-the-box “lit” services from a middle-mile network, like a Virtual Private Network (VPN) or connectivity to cloud providers or the global Internet. If they wish to configure a custom service, they might choose to lease a pair of fiber-optic strands via a dark fiber IRU (a long-term lease) and light the fiber themselves, but there are other options on the Optical Layer between dark fiber and lit services: Optical Services. Optical Services mean purchasing one or more “slices” of the total spectrum of light carried by a fiber pair: a defined amount of bandwidth on either side of a central wavelength. The capacities that a carrier or last-mile provider can obtain through such services typically run into the hundreds of gigabits per second, making Optical Services equivalent to a dedicated high-performance fiber path. Optical services operate in 3 steps:

1. Customer Data Handoff: At the Optical Layer, data signals from the last-mile provider are not modified in any way but turned directly into light pulses of a specific color (wavelength).
2. Transit Along Fiber Backbone: These light pulses are then sent down the fiber and then turned back into customer data signals when they reach the node at the other end
3. Data Arrives At Destination: Depending on the transponder and the width of the spectrum band, one “slice” of the spectrum can support different data throughputs.

Future-facing middle-mile networks feature the ability to provide a customer’s desired capacity on a pair of fiber strands with spectrum services: combining multiple much smaller “slices” (currently 6.25 or 12.5 GHz wide) into one composite “slice” of flexible size. This composite “slice” is treated as a single signal by one pair of Next-Generation Internet (NGI) transponders, which can enable considerably higher data throughputs thanks to recent innovations.