Bendable, low-loss Topas fibers for the terahertz frequency range

Abstract

Abstract:We report on a new class of polymer photonic crystal fibers for low-loss guidance of THz radiation. The use of the cyclic olefin copolymer Topas, in combination with advanced fabrication technology, results in bendable THz fibers with unprecedented low loss and low material dispersion in the THz regime. We demonstrate experimentally how the dispersion may be engineered by fabricating both high-and low-dispersion fibers with zero-dispersion frequency in the regime 0.5-0.6 THz. Near-field, frequencyresolved characterization with high spatial resolution of the amplitude and phase of the modal structure proves that the fiber is single-moded over a wide frequency range, and we see the onset of higher-order modes at high frequencies as well as indication of microporous guiding at low frequencies and high porosity of the fiber. Transmission spectroscopy demonstrates low-loss propagation (< 0.1 dB/cm loss at 0.6 THz) over a wide frequency range. 8845-8854 (2008)

Broadband polymer microstructured THz fiber coupler with down-doped cores

“…aveguides for terahertz (THz) radiation have attracted widespread attention in recent years 1 as the promise of efficiently delivering and confining the THz radiation is one that offers many applications. Much work is still at hand before the waveguides will deliver on that promise.…”

Optical fibre Bragg grating recorded in TOPAS cyclic olefin copolymer

“…Interestingly, Topas is also an ideal material for terahertz fibres, because it becomes transparent with strongly reduced material dispersion in the terahertz frequency range [10].…”

Ultra low bending loss equiangular spiral photonic crystal fibers in the terahertz regime

“…Plastic, 2 metallic ribbon 3 waveguides and polymer PCF 4,5 have demonstrated THz guidance. The latter often utilize a 'drill and draw' 5,6 or 'stack and fuse' 4 technology in their fabrication.…”

“…The latter often utilize a 'drill and draw' 5,6 or 'stack and fuse' 4 technology in their fabrication. Recently, very low loss operation in a PCF made from Topas R polymer has been demonstrated 5 and a new class of porous fibers have also been reported, [7][8][9] though achieving high porosity is not trivial. 9 In this letter, an Equiangular Spiral (ES) PCF design inspired by nature 10,11 in Topas R is presented for THz frequencies.…”

“…A comparison of the ML in the H-PCF (the LMA design), 5 and a ES-PCF (optimized with the same number (36) of air holes as the LMA) is presented where the key fiber parameters used are as follows -for the LMA: =560μm, r=125μm, d/ =0.45 and for the ES-PCF: 7 arms, 5 rings, r o =560μm, r=250μm, θ =27 • . Figure 2 shows the ML and the normalized spot size variation with the bend radius.…”