Shyqyri Haxha

Numerical Analysis of a Photonic Crystal Fiber for Biosensing Applications

This paper presents a theoretical study on a photonic crystal fiber (PCF) surface plasmon resonance biosensor. The proposed PCF sensor introduces the concept of simultaneous detection with H E₁₁^x and H E₁₁^x modes, which opens up some possibilities for multianalyte/multichannel sensing. Analysis was performed which considered the operation of the sensor in both amplitude and wavelength interrogation modes. Typical sensor resolutions of 4×10^-5 RIU and 8×10^-5 RIU with respect to H E₁₁^x and H E₁₁^y, respectively, are reported for the amplitude interrogation mode, while resoutions of 5 × 10^-5 RIU and 6×10^-5 RIU are reported for H E₁₁^x and H E₁₁^y, respectively, for the wavelength interrogation mode.

A Novel Birefrigent Photonic Crystal Fiber Surface Plasmon Resonance Biosensor

A numerical analysis of a novel birefringent photonic crystal fiber (PCF) biosensor constructed on the surface plasmon resonance (SPR) model is presented in this paper. This biosensor configuration utilizes circular air holes to introduce birefringence into the structure. This PCF biosensor model shows promise in the area of multiple detection using HE^x₁₁ and HE^y₁₁ modes to sense more than one analyte. A numerical study of the biosensor is performed in two interrogation modes: amplitude and wavelength. Sensor resolution values with spectral interrogation yielded 5 × 10^-5 RIU (refractive index units) for HE^x₁₁ modes and 6 × 10^-5 RIU for HE^y₁₁ modes, whereas 3 × 10^-5 RIU for HE^x₁₁ modes and 4 × 10^-5 RIU for HE^y₁₁ modes are demonstrated for the amplitude interrogation.

Optimization of microwave properties for ultrahigh-speed etched and unetched lithium niobate electrooptic modulators

Simultaneous phase velocity and characteristic impedance matching of the ultrahigh-speed electrooptic modulators is presented by using the finite-element method (FEM). It is also shown that the dielectric loss in the silica buffer layer is larger than that in the lithium niobate substrate and when these dielectric losses are included, the resulting bandwidth is reduced significantly. It is also shown that for an etched LN structure, it is relatively easier to match both N/sub m/ and Z/sub c/ simultaneously and the resulting optical bandwidth is also greater.

Highly Birefringent Photonic Crystal Fibers With Ultralow Chromatic Dispersion and Low Confinement Losses

Highly birefringent photonic crystal fibers (PCFs) with low confinement loss with ultralow and ultraflattened chromatic dispersions at wide wavelength band are presented. The transverse electric field vector distributions of two linearly polarized fundamental modes, their effective indices, modal birefringence, confinement losses and chromatic dispersion of the proposed PCFs are reported by using full-vector finite-element method (FEM). Significant improvements of PCFs in terms of the birefringence, chromatic dispersion and confinement losses are demonstrated by careful investigation of all air holes in each ring, air holes diameters and hole-to-hole spacing. In addition to this, the polarization beat length results of the proposed PCFs are also reported and discussed thoroughly.

Dual channel planar waveguide surface plasmon resonance biosensor for an aqueous environment

A theoretical study on a dual channel planar waveguide surface plasmon biosensor is presented in this paper. The proposed device consists of a planar waveguide with two active regions. It has been demonstrated that the proposed waveguide sensor can be configured to operate in either multi analyte or self referencing mode. The channel discriminative property of the device is investigated using an eigenmode solver with perfectly matched layers (PML).

Bandwidth estimation for ultra-high-speed lithium niobate modulators

The effects of velocity matching, impedance matching, conductor loss, and dielectric loss on the optical bandwidth of an ultra-high-speed lithium niobate modulator are reported. It is shown that both dielectric loss and impedance matching play a key role for velocity-matched high-speed modulators with low conductor loss. The effects of etch depth, buffer thickness, electrode width, and thegap between the electrodes on device performance are also illustrated.

Design and optimization of a novel surface plasmon resonance biosensor based on Otto configuration

A theoretical study on a novel planar waveguide surface Plasmon Biosensor is presented in this paper. The proposed biosensor has a configuration similar to the Otto excitation mechanism for surface Plasmon polaritons. The performance of the device with respect to key system parameters such as gap-width and device length is investigated using an eigenmode solver with perfectly matched layers (PML). Device resolution of 2.3 x 10(-6) RIU has been demonstrated for an aqueous analyte.

Multi-channel SPR biosensor based on PCF for multi-analyte sensing applications

This paper presents a theoretical investigation of a novel holey fiber (Photonic Crystal Fiber (PCF)) multi-channel biosensor based on surface plasmon resonance (SPR). The large gold coated micro fluidic channels and elliptical air hole design of our proposed biosensor aided by a high refractive index over layer in two channels enables operation in two modes; multi analyte sensing and self-referencing mode. Loss spectra, dispersion and detection capability of our proposed biosensor for the two fundamental modes (HE(11)(x) and HE(11)(y)) have been elucidated using a Finite Element Method (FEM) and Perfectly Matching Layers (PML).

Light field geometry of a standard plenoptic camera

The Standard Plenoptic Camera (SPC) is an innovation in photography, allowing for acquiring two-dimensional images focused at different depths, from a single exposure. Contrary to conventional cameras, the SPC consists of a micro lens array and a main lens projecting virtual lenses into object space. For the first time, the present research provides an approach to estimate the distance and depth of refocused images extracted from captures obtained by an SPC. Furthermore, estimates for the position and baseline of virtual lenses which correspond to an equivalent camera array are derived. On the basis of paraxial approximation, a ray tracing model employing linear equations has been developed and implemented using Matlab. The optics simulation tool Zemax is utilized for validation purposes. By designing a realistic SPC, experiments demonstrate that a predicted image refocusing distance at 3.5 m deviates by less than 11% from the simulation in Zemax, whereas baseline estimations indicate no significant difference. Applying the proposed methodology will enable an alternative to the traditional depth map acquisition by disparity analysis.

Design optimization of polymer electrooptic modulators

A versatile and numerically efficient finite-element method-based approach has been developed and used to solve the associated quasi-static Laplace equation for electrodes, the full-vectorial wave equation for optical waveguides, and the evolutionary beam-propagation method for bend designs, to characterize the Mach-Zehnder-based polymer modulators incorporating ridge-type waveguide structures. The effects of the rib height and the waveguide width on a single-mode operation, the symmetry of the beam profile, the insertion loss, and the bending loss of the polymer rib waveguides are presented. Further, the effect of the rib height, the waveguide width, and the electrode width on the key modulator parameters, such as VpiL, Nm, and Z c are presented, and as a consequence, an optimized design is reported