Optical Signal-to-Noise Ratio in Amplified Systems

This lecture covers the concept of amplifier noise in optical systems, explaining how all amplifiers add noise due to spontaneously emitted photons with random characteristics. The optical Signal-to-Noise Ratio (OSNR) is defined and its measurement with an optical spectrum analyzer is discussed. The lecture delves into EDFA noise, specifically amplified spontaneous emission (ASE), and how it affects OSNR. The impact of amplifier spacing on OSNR is explored, along with an example calculation for determining the maximum transmission distance based on system requirements. The importance of amplifier spacing in achieving high OSNR at the receiver and reducing system cost is highlighted.