Design of Highly Birefringent and Low-Loss Oligoporous-Core THz Photonic Crystal Fiber With Single Circular Air-Hole Unit

Highly birefringent elliptical core photonic crystal fiber for terahertz application

“…It is also observed that, EML increases with the decrease of porosity because reducing porosity means reducing the core air hole diameter which in turn increase the amount of material inside the core area. At optimal design parameters, a very small amount of EML of 0.05 cm −1 is obtained which is comparable with the previously reported[11,12,13,14,15,16,17,18] fibers.…”

“…The obtained dispersion is very low and flat also significantly improved over previously reported optical waveguide designs [11,12,13,14,15,16,17,18], [24,25,26,27,28].…”

“…where n x and n y represents the effective refractive index of x and y polariza- It is also observed that, at higher porosity values the amount of birefringence decreases because such increment of porosity causes some of the useful power propagates outside the core region that reduces the index contrast between the polarization modes which consequently reduces the birefringence. At optimal design parameters, the obtained birefringence is 0.086, which is better than the previously proposed [11,12,13,14,15,16,17,18,28] terahertz waveguides. The main difficulty of designing a terahertz waveguide is its high EML.…”

“…However, their obtained EML as well as dispersion variation was much higher. An oligo-porous core [16] and triple hole core [17] fibers have also been proposed that shows a birefringence of 3 × 10 −2 and 10 −2 respectively.…”

“…In this letter, we introduce a novel Topas based photonic crystal fiber consisting of a conventional hexagonal structure in the cladding and a penta-hole elliptical structure in the core which simultaneously offering ultra-high birefringence and ultra-low near zero flattened dispersion. Several types of core structures including hexagonal [19], rhombic [20], dual hole unit [13], diamond [21], rectangular slot [22], oligo-porous [16], tri-air hole [17], hexagonal structure with elliptical shaped air holes [28] have previously been analyzed. However, to the best of our knowledge, penta-hole elliptical structure inside a hexagonal cladding has not been considered.…”