Abstract

In the past few years, several authors have reported broadband optical amplification using parametric effects in optical fibers.^1,5 This simple technique appears now as a promising solution for fiber WDM systems and opens up a new means to cover actual and future telecommunications windows. In addition to provide broadband and high gain, fiber optical parametric amplifiers (OPA’s) are spectrally flexible, they can operate with low noise features and they offer the possibility to achieve simultaneously wavelength conversion. Indeed, it has been experimentally demonstrated that they can exhibit a gain bandwidth of more than 200 nm, ² a net black-box gain up to 49 dB and a conversion efficiency of 38 dB.³ Moreover, it has been also shown that OPA’s can directly generate a broad and flat gain region by using two pump lasers⁴ or multiple fibers with different group-velocity dispersions.⁵ The latter case has been recently checked against experimental measurements that demonstrate a flattened gain bandwidth of 75 nm in a two fiber OPA scheme.⁶ However, a major limitation of OPA performances lies in the high pumping level. In response to this limitation, highly nonlinear fibers (NLF) that have a large nonlinear coefficient γ^2,3,7 have been proved to be the best candidates for fiber OPA. In this work, we propose and theoretically study a new multi-section OPA configuration based on four NLF’s with different zero-dispersion wavelengths to achieve low-pump power operation (more than one order of magnitude less compared to previous results⁵), as well as broadband and flat parametric gain. Other results are also presented that illustrate the effects of random fluctuations in the zero-dispersion wavelengths and the system performances in a realistic telecommunication configurations.

© 2002 Optical Society of America