Q Factor is a measure of the quality of the optical signal, taking into account the OSNR and BER. The most commonly used metrics for this purpose are the Optical Signal-to-Noise Ratio (OSNR), Bit Error Rate (BER), and Q Factor. Optical. the atmosphere as its propagation medium and Optical Fiber uses silica as its propagation medium. Therefore, in receiving end to provide. In telecommunication, a method for working dispersion that combines two or more types of single mode fiber to create the preferred dispersion over the whole link span has been offered. In the formula, Pi represents the signal power on channel i; Bm represents the equivalent noise.