Dark Fiber - Optical fiber infrastructure (cabling and repeaters) that is currently in place but is not being used. Optical fiber conveys information in the form of light pulses so the "dark" means no light pulses are being sent.
DWDM - Dense Wavelength Division Multiplexing - an optical technology used to increase bandwidth over existing fiber optic backbones.
Gigabite - Gb - 1,024 megabits or 1 billion bits of information.
Latency - the amount of time it takes for a data packet (unit of data) to move across a network connection. It is one of the factors that determines the speed of your network connection. Bandwidth is the other.
Optical Fiber - long strands of glass, thinner than a human hair, which propagate a lightwave signal for use in broadband communications.