Sohel Rana

Extremely High-Birefringent Asymmetric Slotted-Core Photonic Crystal Fiber in THz Regime

We present a thorough numerical analysis of a highly birefringent slotted porous-core circular photonic crystal fiber (PCF) for terahertz (THz) wave guidance. The slot shaped air-holes break the symmetry of the porous-core which offers a very high birefringence whereas the compact geometry of the circular cladding confines most of the power in the fiber-core. The fiber structure reported in this letter exhibits simultaneously ultrahigh modal birefringence of 7.5 × 10-2 and a very low effective absorption loss of 0.07 cm-1 for y-polarization mode at an operating frequency of 1 THz. It is highly anticipated that the slotted-core waveguide would be of very much convenience in many polarization maintaining THz appliances.

Novel porous fiber based on dual-asymmetry for low-loss polarization maintaining THz wave guidance.

In this Letter, we suggest a novel kind of porous-core photonic crystal fiber (PCF) (to the best of our knowledge) for efficient transportation of polarization maintaining (PM) terahertz (THz) waves. We introduce an asymmetry in both the porous-core and the porous-cladding of the structure to achieve an ultra-high birefringence. Besides, only circular air holes have been used to represent the structure, which makes the fiber remarkably simple. The transmission characteristics have been numerically examined based on an efficient finite element method (FEM). The numerical results confirm a high birefringence of ∼0.045 and a very low effective absorption loss of 0.08u2009u2009cm(-1) for optimal design parameters at 1 THz. We have also thoroughly investigated some important modal properties such as bending loss, power fraction, dispersion, and fabrication possibilities to completely analyze the structures usability in a multitude of THz appliances. Moreover, physical insights of the proposed fiber have also been discussed.

A Novel Low-Loss Diamond-Core Porous Fiber for Polarization Maintaining Terahertz Transmission

We report on the numerical design optimization of a new kind of relatively simple porous-core photonic crystal fiber (PCF) for terahertz (THz) waveguiding. A novel twist is introduced in the regular hexagonal PCF by including a diamond-shaped porous-core inside the hexagonal cladding. The numerical results obtained from an efficient finite-element method, which confirms a high birefringence of the order 10-2 and low effective material loss of 0.07 cm-1 at 0.7-THz operating frequency. The proposed PCF is anticipated to be useful in polarization sensitive THz appliances.

Porous core photonic crystal fibre for ultra-low material loss in THz regime

An extremely low-loss porous core circular photonic crystal fibre is presented for terahertz (THz) wave guidance. Much of attention is given to the geometries of the fibre to increase the fraction of power transmitted through core air holes. The finite-element method has been used to compute the modal characteristics of the fibre. Simulation results exhibit an ultra-low material loss of −0.05 cm−1 which is one-fourth of the bulk material loss and almost half of the useful power goes through core air holes at a frequency f = 1 THz. Besides, single-mode properties, confinement loss and dispersion of the fibre are rigorously discussed. The proposed fibre can be fabricated using capillary stacking or sol–gel technique and is useful for transmission applications in the THz frequency band.

A Novel Low Loss, Highly Birefringent Photonic Crystal Fiber in THz Regime

We present a new kind of dual-hole unit-based porous-core hexagonal photonic crystal fiber (H-PCF) with low loss and high birefringence in terahertz regime. The proposed fiber offers simultaneously high birefringence and low effective material loss (EML) in the frequency range of 0.5-0.85 THz with single-mode operation. An air-hole pair is used inside the core instead of elliptical shaped air holes to introduce asymmetry for attaining high birefringence; where the birefringence can be enhanced by rotating the dual-hole unit axis of orientation. The proposed H-PCF provides a birefringence of ~0.033 and an EML of 0.43 dB/cm at an operating frequency of 0.85 THz.

Single-mode porous fiber for low-loss polarization maintaining terahertz transmission

Abstract. We report on a polymer-based porous-core photonic crystal fiber for simultaneous high-birefringent and low-loss propagation of narrowband terahertz (THz) electromagnetic waves. The high birefringence is induced by using rotated elliptical air holes inside the porous-core. The fiber is numerically analyzed with an efficient finite-element method. The simulation results exhibit an extremely high birefringence of ∼0.042 and a very low effective material loss of ∼0.07u2009u2009cm−1 at an operating frequency of 1 THz. Moreover, we have found an optimal rotation angleu2009(θ)=n30u2009u2009deg (n is an odd integer). Other modal features of the fiber, such as confinement loss, power fraction, effective area, bending loss, and dispersion, also have been analyzed. We anticipate that the proposed fiber would be suitable in polarization maintaining THz wave guidance applications.

Spiral Photonic Crystal Fiber-Based Dual-Polarized Surface Plasmon Resonance Biosensor

We numerically demonstrate a surface plasmon resonance biosensor-based on dual-polarized spiral photonic crystal fiber (PCF). Chemically stable gold material is used as the active plasmonic material, which is placed on the outer layer of the PCF to facilitate practical fabrication. Finite-element method-based numerical investigations show that the proposed biosensor shows maximum wavelength sensitivity of 4600 and 4300 nm/RIU in <inline-formula> <tex-math notation=LaTeX>

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

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Extremely low-loss, dispersion flattened porous-core photonic crystal fiber for terahertz regime

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Dispersion flattened, low-loss porous fiber for single-mode terahertz wave guidance

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