Performance Evaluation of SCM-WDM System Using Different Linecoding

TL;DR

This paper evaluates the performance of SCM-WDM optical systems with different line coding schemes under optical beat interference, showing Miller coding significantly improves the signal-to-interference ratio compared to NRZ and Manchester codes.

Contribution

It provides a comparative analysis of line coding schemes in SCM-WDM systems under OBI, highlighting Miller code's superior performance in enhancing SIR.

Findings

Miller code yields higher SIR than NRZ and Manchester codes.

Significant SIR improvement observed with Miller coding at 10 subcarriers.

Results align well with theoretical expectations.

Abstract

This paper investigates the theoretical performance analysis for a subcarrier multiplexed (SCM) wavelength division multiplexing (WDM) optical transmission system in presence of optical beat interference (OBI) which occurs during the photo detection process. We have presented a comparison for improving the performance of SCM-WDM system in presence of OBI. Non-return-to zero (NRZ), Manchester and Miller code (MC) line coding are used for performance investigation of SCM-WDM system. A suitable signal bandwidth is selected and 200 KHz is considered as channel bandwidth. Power spectrum of signal and cross component for those line coding are analyzed. Comparison results are evaluated in terms of signal to OBI ratio for the three linecoding schemes which is called signal to interference ratio (SIR). It is found that there is a significant increase in the SIR by employing Miller code compared to NRZ and Manchester for the same data rate. For example, for a number of subcarriers of 10, the achievable SIR is about -24 dB for Miller coded system compared to -46 dB for NRZ coded system and -49 dB for Manchester coded system. The results are found to be satisfactorily agreed with the expected results.