Four-wave mixing in zirconia-erbium doped fiber – a comparison between ring and linear cavities

Abstract

The generation and performance of the four-wave mixing (FWM) effect in zirconia-erbium doped fibers (Zr-EDFs) is investigated and compared for linear and ring cavities. A 3 m long Zr-EDF with an erbium ion concentration of 3000 ppm and non-linear coefficient value of 14.0 W-1km-1 serves as the non-linear medium in this work. The ring configuration generates sidebands approximately 20 dB higher than the linear configuration, whilst the linear configuration provides a more stable sideband power as the signal wavelength changes. An enhanced ring configuration is also proposed and demonstrated, using only a single tunable laser source (TLS) as the pump wavelength and a 100 m long highly non-linear fiber (HNLF) with a non-linear coefficient of 10.8 W-1km-1. The enhanced ring configuration is capable of generating up to 10 sidebands through the FWM effect with channel spacings of approximately 1 nm each. The proposed enhanced ring design will find many applications as multi-wavelength sources for communications and sensing.