Compensating spectral loss variations in EDFA amplifiers for different modulation formats

In this paper, we investigate the performance of the optical system consisting of chain of EDFA amplifiers for different data formats such as non-return-to-zero (NRZ), return to zero (RZ) and Manchester. Their effect on the spectral loss variations produced in fiber output is analyzed. We show that when the RZ raised cosine and Manchester raised cosine modulation formats are used, the non-linear ties are produced in power spectrum plots which severely distort the signals obtained at the output of the chain of the EDFA amplifiers. On the other hand, the NRZ raised cosine modulation format best compensates the spectral loss variations in the power spectrum plots obtained at the output. We further show that NRZ raised cosine has good eye opening as compared to other modulation formats.