Azizur B. Rahman

Implementation of high speed optical universal logic gates using the electro-optic effect-based Mach–Zehnder interferometer structures

The universal logic gates are the most important logic gates responsible for optimized design of different types of complex digital logic circuits. It is of great interest to implement the function of universal logic gates such as NAND and NOR logic gates using the concepts of electro-optic effect. The smart use of electro-optic effect can provide very effective optical power switching devices. The implementation of universal logic gates operation in the optical domain can improve the performance of the devices and includes the advantages of the optical communication system. The proper configuration of Mach–Zehnder interferometer working on the principle of electro-optic effect can provide the optical responses equivalent to the NAND and NOR logic gates. The proposed devices can be analyzed to check the various performance affecting parameters in order to specify the physical parameters.

Low-Loss Hollow Core Plastic Photonic Band-Gap Fiber for Efficient THz Transmission

We report design of a plastic photonic band-gap fiber for efficient high power THz transmission over a wide spectral range (1.65 ~ 1.95 THz) with low-loss coefficient (< 4 m-1) and low-dispersion (< 10 ps/km.nm).

Single mode and single polarization operation in photonic crystal fibers

A modal solution approach based on the powerful, full-vectorial, H-field based finite element method (FEM) has been used to analyze the single mode operation of a PCF. Modal solutions of the fundamental modes of highly birefringent PCFs have been obtained. The FEM with perfectly matched layer condition has been used to characterize the leakage loss and the differential loss between the polarized modes of PCFs. The design of a single-mode single-polarization PCF has also been proposed.

Challenges of Multicore Fiber Application in Next Generation Short Reach Optical Interconnects

Major challenges facing optical interconnect configuration based on 8-core multicore fiber is addressed to meet the stringent requirements of forthcoming bandwidth intensive short reach communication links and silicon photonic transceivers.

Light-sound interactions in Tellurite Microstructured Fiber

Interactions of acoustic modes with optical modes are presented by using full-vectorial finite element based approaches for a Tellurite microstructured fiber. Results on the SBS frequency shift and the overlap between acoustic and optical modes are also shown.

Efficient Terahertz Generation in a Novel Microstructured-Core Double Clad Plastic Fiber

Microstructured-core double clad plastic fiber (MC-DCPF)-based efficient THz source is designed at 3 THz by exploiting non-linear four-wave mixing. Maximum power transfer efficiency > 3×10-2 is achievable in the 65 meter long proposed MC-DCPF.

Low-loss THz Waveguides and Devices

A rigorous full-vectorial modal solution approach based on the computationally efficient finite element method is used to design low-loss THz waveguides, and for the designs of Quantum cascade lasers, power splitters and narrow-band filters

Dispersion characteristics of plasmonic waveguides for THz waves

Today there is an increasing surge in Surface Plasmon based research and recent studies have shown that a wide range of plasmon-based optical elements and techniques have led to the development of a variety of active switches, passive waveguides, biosensors, lithography masks, to name just a few. The Terahertz (THz) frequency region of the electromagnetic spectrum is located between the traditional microwave spectrum and the optical frequencies, and offers a significant scientific and technological potential in many fields, such as in sensing, in imaging and in spectroscopy. Waveguiding in this intermediate spectral region is a major challenge. Amongst the various THz waveguides suggested, the metal-clad waveguides supporting surface plasmon modes waves and specifically hollow core structures, coated with insulating material are showing the greatest promise as low-loss waveguides for their use in active components and as well as passive waveguides. The H-field finite element method (FEM) based full-vector formulation is used to study the vectorial modal field properties and the complex propagation characteristics of Surface Plasmon modes of a hollow-core dielectric coated rectangular waveguide structure. Additionally, the finite difference time domain (FDTD) method is used to estimate the dispersion parameters and the propagation loss of the rectangular waveguide.

Optical fibre sensors - can they meet current and future industrial measurement challenges?

Potential solutions using optical fibre sensors to the challenges of advanced measurement needs over a wide range for industry will be explored and their suitability for future applications discussed.

Modal hybridism of polarization maintaining photonic crystal fibers by using a full-vectorial finite element method

Modal solutions for photonic crystal fibers with circular air holes in a hexagonal matrix are presented, by using a rigorous full-vectorial finite element-based approach. The effective indices, mode field profiles, spot-sizes, modal hybridness, modal birefringence and group velocity dispersion values have been determined and are shown and discussed. The effect of Kerr-type material nonlinearity on the modal properties and the spot-size are also shown in this paper.