Bend-Insensitive and Low-Loss Porous Core Spiral Terahertz Fiber

Hybrid porous‐core microstructure terahertz fibre with ultra‐low bending loss and low effective material loss

“…The calculated α BL for R = 1 and 2 cm is 5.24 × 10 −13 and 1.97 × 10 −24 cm −1 , respectively, when D core = 350 µm, porosity = 52% and f = 1 THz. These results are comparable with the previously published results in [14, 19, 20]. Note that the lowest value of R is considered as 1 cm since further reduction of the bending radius will need excessive pressure and temperature that may deform the cross‐section of the proposed fibre [20].…”

“…The direct calculation of the bending loss is a cumbersome task since it associates with complex numerical calculations [22]. To avoid such calculations, we have adopted an easy‐to‐evaluate approximate formula to calculate the bending loss ( α BL ), which is expressed by [14, 19, 20, 22] where β is the propagation constant which is given by β = 2 πn eff / λ , A eff is the effective area, R is the bending radius and F ( x ) = x −1/2 e − x . The effective area can be found from the following equation [14]: where I ( r ) = | E | 2 is the electric field intensity.…”

“…The effective area can be found from the following equation [14]: where I ( r ) = | E | 2 is the electric field intensity. The effective index of the cladding is assumed to be 1 since the cladding is mostly holey [14, 19, 20]. This approximate formula shows a good degree of accuracy, which has been experimentally validated in [22].…”

“…Besides, a porous‐core THz MOF has been demonstrated in [19], which showed a bending loss of about 0.023 cm −1 for a tight‐bending radius of 1 cm. Recently, Islam et al [20] proposed a porous‐core spiral MOF having an extremely low bending loss of 4.16 × 10 −16 cm −1 at 1.0 THz; however, this MOF showed a high EML of 0.1 cm −1 . Very recently, a rhombic‐shaped core MOF has been demonstrated by the authors showing an ultralow bending loss of 3.04 × 10 −11 cm −1 and a low EML of 0.089 cm −1 at 1.0 THz [14].…”

A Novel Hexahedron Photonic Crystal Fiber in Terahertz Propagation: Design and Analysis

“…In the last several decades, numerous articles have been published to minimize the effective material loss (EML), confinement loss, and scattering loss, and to increase the core power fraction and effective area of THz PCF. In 2013, Islam et al [14] proposed spiral THz PCF and gained effective area and EML of 1.82 × 10 7 m 2 and 0.10 cm −1 at 1 THz. The EML of propsed PCF was very high and did not calculate two crucial parameters like V e f f and core power fraction.…”