Mustafa A. G. Abushagur

Nanoplasmonic couplers and splitters

In this paper, we present novel designs and analysis of ultra-compact couplers and 1 x 2 splitters based on plasmonic waveguides. Numerical simulation shows coupling efficiency up to 88% for the former one and 45% for each branch for the latter one. The proposed coupler design has the advantages of improving the alignment tolerance of the plasmonic waveguide with respect to the dielectric waveguide and broadening the spectrum response of the splitter.

Efficient light coupling between dielectric slot waveguide and plasmonic slot waveguide

An efficient coupler between a dielectric waveguide and a plasmonic metal-insulator-metal (MIM) waveguide is proposed, modeled, fabricated, and characterized. Based on the platform of a silicon slot waveguide, a quasi-MIM plasmonic junction is formed via e-beam lithography and lift-off process. Coupling efficiency between the silicon slot waveguide and plasmonic waveguide up to 43% is obtained after normalizing to reference waveguides at 1550 nm. This coupling scheme can be potentially used for fast optical switching and small-footprint optical modulation.

Efficiently squeezing near infrared light into a 21nm-by-24nm nanospot

Recent work demonstrated light transmission through deep subwavelength slits or coupling light into waveguides with deep subwavelength dimension only in one direction. In this paper, we propose an approach to squeeze light (lambda = 1550 nm) from a dielectric waveguide into a deep subwavelength spot. Vertical confinement is achieved by efficiently coupling light from a dielectric waveguide into a 20-nm metal-dielectric-metal plasmonic waveguide. The horizontal dimension of the plasmonic waveguide is then tapered into 20 nm. Numerical simulation shows that light fed from a dielectric waveguide can be squeezed into a 21 nm-by-24 nm spot with efficiency 62%.

Novel three-axes fiber Bragg grating accelerometer

We are proposing a novel application for fiber optic sensors in measuring acceleration. This novel design accelerometer is based on a fiber Bragg grating (FBG). The device we are proposing is capable of measuring acceleration in three axes simultaneously.

New pumping scheme for high gain and low noise figure in an erbium-doped fiber amplifier

We propose a new pumping method for optical fiber amplifiers at 1480nm and 980nm that is able to provide high gain and low noise-figure. The gain and noise figure obtained were 38.3dB and 5.5dB with an improvement of 3.8dB and 1.4dB, respectively, at 1550nm, for -30dBm input power when compared to its counter-pumped design. This design also delivers higher gain and lower noise figure when compared to the common bi-directional dual-pumped designs. A power conversion efficiency of 44.5% was achieved in this design.

Radii-changing effect on the coupling efficiency between a silica waveguide and a planar photonic crystal

In this paper, we designed different structures for PPC tapered waveguide to enhance the coupling between silica waveguide (SWG) and planar photonic crystal (PPC). The designed structures are based on changing the radii of the inner PPC tapered waveguides crystals before and after adding extra defects. We found that above 88% transmission efficiency is possible by using extra defects followed by radii changes. We also found that changing the operating wavelength from 1.55μm to 1.558μm increases the transmission efficiency to 90% since the field is more confined at the later wavelength.

Ultra-compact nanoplasmonic splitter

We present novel designs and fabrication of ultra-compact coupler and 1×2 splitter using plasmonic waveguides. The coupling efficiency is 88% for the former one and 45% for each branch for the latter one.

Crosstalk Reduction in Square Cavities

Theoretically and experimentally, we demonstrate that low crosstalk between two crossed line-defect waveguides formed in a square lattice photonic crystal (PC) structure can be achieved using a resonant cavity at the intersection area. The PC resonator consists of cubic air-holes in silicon air-holes. The Q-factor of the cavity can be changed by increasing the number of holes that form the cavity. The theoretical and experimental crosstalk results are about -40 dB and -20 dB, respectively.

Ultra low cross talk in crossed strip waveguides with the assistance of a photonic crystal cavity

In this paper, ultra low cross talk is achieved by using a resonant cavity at the intersection between two strip waveguides formed in a square lattice photonic crystal structure (PhC). Two PhC structures are studied: one consists of cylindrical rods and another consists of cubic rods. The Q-Factor of the cavity is changed by increasing the number of rods that form the cavity and by decreasing the spacing between the waveguide and the cavity. Our two dimensional simulation results show that the latter method resulted in cross talk reduction of more than 21 dB for both structures. The overall cross talk was -90.50 dB for the cylindrical rods structure and -105.0 dB for the cubic rods structure. The optimized PhC structures were fabricated on a silicon-on-insulator platform. The rods were buried in silicon oxide in order to maximize the photonic band gap and provide index guiding in the vertical direction.

Education for 21st Century Microelectronics and Semiconductor Technology

The semiconductor industry has experienced exceptional double-digit growth over the past 25 years, fueled by strong demand in end-use markets such as computing, communications, consumer appliances, and industrial applications driven by the Moores law. The industry has already announced its readiness for the 45 nm node in production. The curricula developed by Rochester Institute of Technology (RIT) have kept pace with the rapid advancements sharing 25 of the 40 years the Moores Law and have contributed significantly in generating the workforce and research for this growing high tech industry. This paper describes our unique undergraduate and graduate programs in Microelectronic and Microsystems Engineering.