Optical Amplifiers……….its Payback or Trade-off.

Amplifier noise is a severe problem in system design. A figure of merit here is the optical signal-to-noise ratio (OSNR) requirement of the system. The OSNR specifies the ratio of the net signal power to the net noise power. It is a ratio of two powers; therefore, if a signal and noise are both amplified, system OSNR still tells the quality of the signal by calculating this ratio. System design based on OSNR is an important fundamental design tool.

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OSNR is not just limited to optical amplifier-based networks. Other active and passive devices can also add noise and create an OSNR-limited system design problem. Active devices such as lasers and amplifiers add noise. Passive devices such as taps and the fiber can add components of noise. In the calculation of system design, optical amplifier noise is considered the predominant source for OSNR penalty and degradation. That does not imply unimportance to other sources of OSNR penalty.

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