Computation of optical waveguide interaction for quantum gates implementation

The system of two coupled optical dual-mode waveguides is considered. The coupling of the system is studied to find a circuit for building a control switch for two qubit gates. The classical coupled mode theory is applied and the exact expressions for coupling coefficients are derived. The parameters of the system for performing the desired operations are numerically computed and analysed. The system describing the influence of intermodal interactions is solved numerically. The distortions are analysed.

Analysis of Wavelength Sensitivity of Coupling Coefficients and Inter-core Crosstalk in a 9 core Multi-core Fiber

Wavelength dependence of coupling coefficients and inter-core crosstalk in a 9-core homogeneous multi-core optical fiber (MCF) are investigated analytically. The analysis is further extended to evaluate the mean crosstalk power at the output of any core with light launched into other core of the MCF. Propagation length dependence of mean crosstalk power is investigated using both coupled mode theory (CMT) and coupled power theory (CPT). CPT based results show that mean crosstalk power linearly dependent on propagation distance, and it is higher for higher values of coupling coefficient. On the other hand, the mean crosstalk power is found to oscillate with the propagation distance in case of CMT. It is also observed that the mean crosstalk power (dB) is more prominent at a lower wavelength for a given propagation distance. The behavour of relative crosstalk power is also investigated analytically where it is noticed that the relative crosstalk power increases almost linearly with core pitch and with wavelength. It is also seen that the relative crosstalk power (dB) is more in an MCF with lower number of cores when it is varied with respect to wavelength. This is due to the increase of core pitch under the same cladding diameter and cladding thickness limitations.

Transmission and Generation of Orbital ANGULAR Momentum Modes in Optical Fibers

The orbital angular momentum (OAM) of light provides a new degree of freedom for carrying information. The stable propagation and generation of OAM modes are necessary for the fields of OAM-based optical communications and microscopies. In this review, we focus on discussing the novel fibers that are suitable for stable OAM mode transmission and conversion. The fundamental theory of fiber modes is introduced first. Then, recent progress on a multitude of fiber designs that can stably guide or generate OAM modes is reviewed. Currently, the mode crosstalk is regarded as the main issue that damages OAM mode stability. Therefore, the coupled-mode theory and coupled-power power theory are introduced to analyze OAM modes crosstalk. Finally, the challenges and prospects of the applications of OAM fibers are discussed.

Numerical & Analytical Modeling of Plasmonic Filter with High Q-Factor Based on "Nanostructured Resonator"

In this paper, to achieve high quality filters, nanostructured plasmon resonators are proposed. The structure of proposed resonator is based on metal-dielectric-metal configuration and is designed in the range of 1550 nm telecommunication wavelength. To evaluate the proposed structure, finite difference time domain method as well as analytical method of coupled mode theory have been used. To obtain optimal results, the effects of the number of waveguides as well as the radius of circular and ring waveguides were investigated. The appropriate results will be obtained by considering a strong coupling between the incoming light and the surface plasmon. In addition, two transient and static wave structures have been used to evaluate the structure. The simulation results show that besides filtering behavior of the structure, it is possible to control the surface plasmon propagation speed in the proposed structure. Therefore, it is expected that the proposed structure will be used in many parts of a telecommunications link, including multiplexers, and multiplexers.