Computing of influence of stimulated Raman scattering in DWDM telecommunication systems

Abstract

Bandwidth and quality of service requirements in transport networks are constantly growing. One of the probable solution to this problem is optical transmission systems usage based on Dense Wavelength Division Multiplexing (DWDM) technology. However, due to increasing number of optical channels and channel rates in the system, a number of limitations occurs caused by harmonic distortion. Primarily, these constraints affect the allowable power of the optical signal in fiber. The work is devoted to the method of power calculation, which is redistributed between the optical channels of DWDM systems due to the impact of the stimulated Raman scattering effect (SRS). In case of energy redistribution channels degradation with higher frequencies take place, thereby the number of bit error rate (BER) increase. It is shown that SRS could affect system performance in case of inefficient frequency diversity and high input signal power. Therefore, the Raman scattering effect calculation is required in high load multi-channel DWDM systems deployment. The proposed calculation method allows to determine: SRS appearance threshold power, the amount of the main signal power loss for each channel, the remaining total energy in the target channel, the amount of energy that passes from the short wavelengths channels to longer wavelengths channels. The 8-channel DWDM system calculation example has been shown.