In the context of wavelength-division multiplexing, an alien wavelength is a "colored" optical signal that is originated from equipment not under the direct control of the transmission network operator. This technique was first mentioned in 2009.[1]
Alien Wave transport involves transparent transmission of colored optical channels over pre-existing third-party physical infrastructure. In other words, Alien Wave transport implies an innovative spectrum utilization arrangement between an optical infrastructure owner and a bandwidth crippled customer. The fact that multiple providers co-exist and utilize the common fiber and optical layer infrastructure turns out to be a viable and cost-effective way to scale-up network capacity through minimal capital and operational investments.
A practical example of an Alien Wave implementation is one where network resources owned by one carrier are being utilized to transport optical channels that are in the control of a secondary carrier. The possibility of Alien Wave insertion without any impact to existing services has resulted in a rapid acceptance of this technology by the telecom service provider community.