In the present invention, methods and systems for fabricating novel LPFGs are taught. Fabrication is preformed by focusing a CO.sub.2 laser beam having a diameter of 30 to 40 .mu.m onto a fiber, such fiber being fixed and weighted on either ends. The variations of transmission spectrum and polarization dependent (PDL) loss of the CO.sub.2 laser-grooved LPFGs with different fabrication parameters as functions of applied as functions of applied tensile stain are demonstrated and evaluated.