Optimization of peak transmittivity in a non-linear fiber loop mirror—an accurate analysis

Abstract

This paper presents the amplification and shaping characteristics of optical beat signal using a combination of non-linear fiber loop mirror (NFLM) and erbium doped fiber amplifier (EDFA). Power levels of beat signal for peak transmittivity (Tp) to be unity have been calculated with an amplifier inside NFLM (NFLM-I) and outside NFLM (NFLM-O). For coupling ratio f<0.35 in the loop mirror, NFLM-O is found to be a more appropriate choice for shaping of the beat signal. We investigate the effect of incorporating saturable gain and fiber losses in computing accurate peak power levels for Tp. Neglecting these effects will drastically reduce Tp. In addition, it was found that the amplification and shaping characteristics of beat signal can be made remarkably insensitive to increase in input power levels when gain saturation of EDFA is included.