Study of dispersion compensation schemes in a point to point transmission with cascaded optical amplifier

Abstract

A theoretical analysis is carried out to evaluate the efficiency of two different dispersion compensation schemes, viz. lump compensation and even compensation to minimize the effect of group velocity dispersion (GVD ) on the performance of an optical CPFSK point to point transmission system using MZI based direct detection receiver. The analysis is extended to linecoded CPFSK system with three line-coding schemes, viz. Alternate mark inversion (AMI), Miller code or Delay modulation (DM) and Manchester code(MC). The analysis is also carried out to find out the impact of SPM with GVD compensation. The analysis includes the effect of accumulated amplifiers spontaneous emission (ASE) noise, signal -ASE noise, ASE-ASE beat noise, laser phase noise and receiver noise. The statistics of the phase fluctuations due to chromatic dispersion in the presence of filtering effect and laser phase noise are determined analytically and is used to determine the bit error probability of the direct detection FSK receiver. The analysis is first carried out for NRZ data pattern and then extended to line-coded data patterns with three different linecoding schemes, viz. AMI, DM, MC to investigate the effectiveness of the linecoding schemes in presence of dispersion. Following the theoretical analysis, the bit error rate (BER) performance of the optical link is evaluated for NRZ . and line-coded data pattern at a bit rate of 10 Gb/s for different system parameters. The power penalty suffered by the system due to the system imperfections mentioned above at BER=lO.9 is evaluated. The improvement in system performance due to the use of compensation schemes is then determined for NRZ data. Performance degradation due to SPM is also evaluated.