Porous fibers: a novel approach to low loss THz waveguides

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

“…The parameters of the porous fiber are taken from the literature. 8 For the H and ES-PCF, the normalized spotsize is small and rises only when frequency decreases below 0.4 THz (approaching cut off). 16 In the case of porous fibers, the cut-off region starts when f≈0.8 THz and thus the operating bandwidth of the porous fibers may not be as large as that of ES-PCF.…”

“…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.…”

Porous-core honeycomb bandgap THz fiber

“…Currently there is much research invested in lowering the loss by forcing a large part of the radiation to propagate in air while still being confined to a waveguide, i.e., subwavelength fiber [8], porous fibers [10,11], and hollow-core fibers. Of these, the hollow-core fiber is the least sensitive to outside perturbations, and thus the fiber can be handled without altering the propagation properties.…”

Direct probing of evanescent field for characterization of porous terahertz fibers

“…[1][2][3] Porous polymer fibers-air-clad fibers with subwavelength features embedded within the core-have been identified as a means of achieving low loss, low dispersion and high birefringence for guiding the THz pulses. [4][5][6] Maintaining the polarization of the propagating field in THz waveguides-by using asymmetrical subwavelength air holes 6,7 -makes these fibers a good substitute for free-space, where the polarization state of the THz field is always preserved. Two types of porous fibers, i.e., with symmetrical and asymmetrical features, have been fabricated exploiting the extrusion technique.…”