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Understanding Crosstalk in Fiber Optic Networks

fiber optic crosstalk optical network wdm isolation

This page explains the concept of crosstalk in fiber optic networks.

The undesired coupling from one channel to another is referred to as crosstalk. This phenomenon is illustrated in Figure 1.

Crosstalk in fiber

Far End Crosstalk

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 isolated from port-1. Crosstalk is typically expressed in dB.

In WDM (Wavelength Division Multiplexing) systems, the signals in the two output ports will have different wavelengths. In this case, the term “isolation” is used instead of “far end crosstalk” to describe the separation between the signals.