Receiver noise includes thermal noise, dark current noise, and quantum noise. OSNR for each level and for complete signal can be defined The signal at the output of an optical amplifier in response to a noise free signal at the input is The following formulation accounts for all noise terms that can be treated as Gaussian noise due to the optical amplifier At the receiver. Optical receivers convert incident optical power P in into electric current through a photodiode. The relation Ip = R Pin assumes that such a conversion is noise free. The challenge is to find a way to determine the. The amount of noise present in a receiver will be the primary factor that determines the receiver's sensitivity. The noise sources that are commonly. Receiver sensitivity is a critical parameter in optical communication systems, determining the minimum optical power required to achieve a specified bit error rate (BER) or signal-to-noise ratio (SNR).
