The undesired coupling from one channel to another is referred to as crosstalk. This phenomenon is illustrated in Figure 1. Far End Crosstalk is defined as the ratio of optical power from output port-1 to output port-2, assuming both ports operate at the same wavelength. Normally, port-2 is. In optical fiber systems, crosstalk (also known as optical coupling) occurs when light from one fiber leaks into another fiber, resulting in interference that can degrade the signal quality. This is especially problematic in systems where multiple fibers are bundled together, such as fiber-optic. WDM systems allow the transmission of various optical signals through a single fiber optic cable. The crosstalk in optical networks incorporating WDM transmission can be either intra-channel. Crosstalk is a type of noise signal that corrupts the actual signal while transmission through the communication medium. It mainly occurs in communication. The optical technology provides the possibility of significantly increase the transmission capacity and, by the use of wavelength division multiplexing technique, also allows switching and routing functions to be accomplished directly in the optical domain, without the need to convert the high. In multichannel communication systems, crosstalk between channels is a problem that must be considered. Typically, the crosstalk should be less than --20 dB.
