GeSbSeTe-based high extinction ratio optical modulator.

In this paper, a design for a high extinction ratio Mach-Zehnder optical modulator is proposed. The switchable refractive index of the germanium-antimony-selenium-tellurium (GSST) phase change material is employed to induce destructive interference between the waves passing through Mach-Zehnder interferometer (MZI) arms and to realize amplitude modulation. A novel, to the best of our knowledge, asymmetric input splitter is designed for the MZI to compensate for unwanted amplitude differences between MZI arms and increase the modulator performance.

Efficient binary and QAM optical modulation in ultra-compact MZI structures utilizing indium-tin-oxide.

A design for a CMOS-compatible active waveguide is proposed in which the epsilon-near-zero (ENZ) property of the indium-tin-oxide (ITO) is used to induce large variations in the real and imaginary parts of the waveguide effective index. The proposed waveguide comprises a TiN/HfO/ITO metal-oxide-semiconductor (MOS) structure where the speed and power consumption are significantly improved by the application of the TiN and realization of double accumulation layers in the ITO. Simulations show the insertion loss (IL) of 0.

High-performance electro-optical switch using an anisotropic graphene-based one-dimensional photonic crystal.

A novel electro-optical switch is proposed and investigated using the transfer matrix method (TMM) and three-dimensional finite-difference time-domain (3D FDTD) analysis at the near-infrared range. The structure is made of a defect at the middle of a one-dimensional photonic crystal. The defect consists of two anisotropic graphene (AG) sheets separated by a dielectric layer.

Design and numerical analysis of a high-performance optical modulator based on Si-VO Bragg grating waveguide.

Design and numerical characterization of a high-performance -based optical modulator are proposed. The modulation is achieved by the phase transition of in a Bragg grating which can be formed by the selective deposition on a silicon strip waveguide. The interplay of the Bragg reflection and the inherent loss of the metal phase is used to increase the extinction ratio (ER) while the similarity of the refractive indices of the silicon and insulator phase resulted in a low insertion loss (IL).

Spectral response, dark current, and noise analyses in resonant tunneling quantum dot infrared photodetectors.

Reduction of dark current at high-temperature operation is a great challenge in conventional quantum dot infrared photodetectors, as the rate of thermal excitations resulting in the dark current increases exponentially with temperature. A resonant tunneling barrier is the best candidate for suppression of dark current, enhancement in signal-to-noise ratio, and selective extraction of different wavelength response. In this paper, we use a physical model developed by the authors recently to design a proper resonant tunneling barrier for quantum infrared photodetectors and to study and analyze the spectral response of these devices.

Electrochemical hydrogen evolution of multi-walled carbon nanotube/micro-hybrid composite decorated with Ni nanoparticles as catalyst through electroless deposition process.

Hydrogen evolution of multi-walled nanotube (MWCNT)/micro-hybrid polymer composite, decorated with Ni nanoparticles through electroless deposition process is studied by the electrochemical method. Cyclic voltammetry (CV) is utilized to clearly study the electrochemical hydrogen storage/evolution behavior of the composite through a potential window ranging from -1.60 to +0.