Carrier and transport slang for one wavelength carrying its own signal, especially on a WDM system where many wavelengths share a fiber pair. A lambda can be sold as a service, so customers lease a 10G or 100G lambda without buying dark fiber. Ops staff talk about turning up, moving or protecting a lambda the way they would talk about a circuit.
We've got two lambdas left on the DWDM between the data centers, so the new 100G turn-up has to wait for the shelf upgrade.
Also heard as
- wavelength
- wave
Do not mix it up with
- Window: A window is a broad low-loss band; a lambda is one channel inside it.
Related terms
WDM
Wavelength Division Multiplexing: sending several signals on different wavelengths over the same fiber.
Window
A wavelength region where fiber loss is low enough to run links, such as 850, 1310 or 1550 nm.
Dark fiber
Installed fiber with no transmission equipment attached, either spare or leased bare to a customer who lights it.
Lit
Describes a fiber that is carrying live traffic from active equipment, as opposed to dark.