ABSTRACT: An optimal design of photonic crystal optical fibers forsimultaneous dispersion compensation and Raman amplification is inves-tigated by numerical simulation using the finite-difference simultaneousover-relaxation method. The proposed fiber was fabricated and experimen-tal characterization results are presented. © 2007 Wiley Periodicals, Inc.Microwave Opt Technol Lett 49: 872–874, 2007; Published online inWiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22294 Key words: photonic crystal fiber; microstructured fiber; Raman ampli-fication; dispersion compensation 1. INTRODUCTION Dispersion compensating fibers (DCFs) are fundamental compo-nents in high-speed optical communication systems. In addition,by providing a suitable pump beam, it is possible to achieveRaman amplification within these fibers and compensate the DCFloss [1]. The end result is a transparent dispersion compensatingmodule, which improves the optical system margin and powerbudget. One drawback still remaining arises from the fact thatconventional Raman amplifiers require relatively high opticalpower densities and/or long interaction lengths.As an alternative, photonic crystal fibers (PCFs) have beenintensively investigated in the past few years. Very high negativevalues of the dispersion coefficient D [2] as well as extremelyefficient Raman amplification in short fiber lengths [3] have al-ready been experimentally demonstrated. These remarkable resultspromise to alleviate the drawbacks listed above and have recentlymotivated theoretical investigations concerning the association ofRaman amplification and dispersion compensation in PCFs [4].However, an experimental demonstration is still to be carried out.In this framework, the aim of our overall investigation is toproposeandimplementasimplifiedPCFdesign,forthesamepurposeof simultaneous Raman amplification and dispersion compensation,by using an uniform geometry in which pitch and hole radius remainconstant along the fiber cross-section. Although recognizing the flex-ibility of dual-core designs [4], we seek to demonstrate that it ispossible to obtain comparable results with uniform structures, therebyreducing fabrication effort and complexity.The paper starts by presenting results concerning the determi-nation of the PCF geometry. Next, we describe our efforts tofabricate the proposed fiber. Finally, experimental results concern-ing Raman and dispersion characteristics, towards the final design,are discussed.
[1]
Lars Gruner-Nielsen,et al.
Raman amplification for loss compensation in dispersion compensating fibre modules
,
1998
.
[2]
W.-P. Huang,et al.
Design and optimization of photonic crystal fibers for broad-band dispersion compensation
,
2003,
IEEE Photonics Technology Letters.
[3]
K. Lyytikainen,et al.
Control of complex structural geometry in optical fibre drawing
,
2004
.
[4]
Murilo A. Romero,et al.
Use of a novel wide-angle FD-BPM for loss performance assessment in randomly perturbed photonic crystal fibers
,
2005
.
[5]
Kunimasa Saitoh,et al.
Novel design of inherently gain-flattened discrete highly nonlinear photonic crystal fiber Raman amplifier and dispersion compensation using a single pump in C-band.
,
2005,
Optics express.
[6]
D J Richardson,et al.
Raman effects in a highly nonlinear holey fiber: amplification and modulation.
,
2002,
Optics letters.
[7]
Murilo A. Romero,et al.
A semivectorial method for the modeling of photonic crystal fibers
,
2003
.