  Graded index microstructured polymer optical fiber incorporating a specially
designed air-hole array featuring variable air-hole diameters and inter-hole
separation is proposed, fabricated and characterized in view of the fiber
potential applications in low-loss, low-dispersion terahertz guidance. The
proposed fiber features simultaneously low chromatic and intermodal
dispersions, as well as low loss in the terahertz spectral range. We then
experimentally demonstrate that proposed fibers exhibit smaller pulse
distortion, larger bandwidth and more reliable excitation when compared to the
porous fibers of comparable geometry.
