Mohamad Halim Abd. Wahid

Performance Study of Two-Dimensional Orthogonal Systolic Array

The systolic array implementation of artificial neural networks is one of the ideal solutions to communication problems generated by highly interconnected neurons. A systolic array is an arrangement of processors in an array where data flows synchronously across the array between neighbours, usually with different data flowing in different directions. The simulation of systolic array for matrix multiplication is the practical application in order to evaluate the performance of systolic array. In this paper, a two-dimensional orthogonal systolic array for matrix multiplication is presented. Perl scripting language is used to simulate a two-dimensional orthogonal systolic array compared to conventional matrix multiplication in terms of average execution time. The comparison is made using matrices of size 5xM versus Mx5 which M ranges from 1 to 10, 10 to 100 and 100 to 1000. The orthogonal systolic array results show better average execution time when M is more than 30 compared to conventional matrix multiplication when the size of the matrix multiplication is increased.

The effect of signal repetition rate, injected current and switching window on cross-phase modulation in SOA-NOLM

The cross phase modulation (XPM) has an important impact on todays high speed dense wavelength division multiplexing optical fiber communication systems. In order to obtain high conversion speed and strong non-linearity, semiconductor optical amplifier nonlinear optical loop mirror (SOA-NOLM) is operated with large bias current and high optical powers. In this paper, an investigation of XPM on the SOA-NOLM with reference to variable SOAs currents, speed and switching window is presented. Furthermore, signal induced phase shift dependence on bias current of the SOA and optimized loop parameters are also included.

SOA characterization for AND logic operation on SOA based NOLM

We present a characterization of Semiconductor Optical Amplifier (SOA) in nonlinear optical loop mirror (NOLM). An SOA-NOLM has been modeled and simulated in OptiSystem environment. In this simulation, optical data pulse and optical control pulse are generated by using two difference CW laser sources at wavelength 1542 nm and 1555 nm wavelength respectively. SOA gain can be increased to 42dB for 500mA in SOA current gain simulation. By varying the SOA input wavelength the output gain is just slightly changed from 41.2dB to 41.6dB for the wavelength range simulated. The characterized SOA also show the gain will be saturated at 10dBm. The recovery time for this type of SOA reached 100pS when the SOA injected with 500mA input current. All this SOAs characterization is performed in order to suit an analysis of various parameters that affect the performance of AND logic operation based on SOA-NOLM.

Methodological comparison on OLED and OLET fabrication

The potential of organic semiconductor devices for light generation is demonstrated by the commercialization of display technologies based on organic light emitting diode (OLED). In OLED, organic materials play the role of light emission once the current is passed through. However, OLED do have major drawbacks whereby it suffers from photon loss and exciton quenching. Organic light emitting transistor (OLET) emerged as the new technology to compensate the efficiency and brightness loss encountered in OLED. The structure has combinational capability to switch the electronic signal such as the field effect transistor (FET) as well as light generation. The aim of this study is to methodologically compare and contrast fabrication process and evaluate feasibility of both organic light emitting diode (OLED) and organic light emitting transistor (OLET). The proposed light emitting layer in this study is poly [2-methoxy-5- (2’-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV).The potential of organic semiconductor devices for light generation is demonstrated by the commercialization of display technologies based on organic light emitting diode (OLED). In OLED, organic materials play the role of light emission once the current is passed through. However, OLED do have major drawbacks whereby it suffers from photon loss and exciton quenching. Organic light emitting transistor (OLET) emerged as the new technology to compensate the efficiency and brightness loss encountered in OLED. The structure has combinational capability to switch the electronic signal such as the field effect transistor (FET) as well as light generation. The aim of this study is to methodologically compare and contrast fabrication process and evaluate feasibility of both organic light emitting diode (OLED) and organic light emitting transistor (OLET). The proposed light emitting layer in this study is poly [2-methoxy-5- (2’-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV).

The study of non-fouling and non-specific cellular binding on functionalized surface for mammalian cell identification and manipulation

Surface functionalization has emerged as a powerful tool for mapping limitless surface-cell membrane interaction in diverse biomolecular applications. Inhibition of non-specific biomolecular and cellular adhesion to solid surfaces is critical in improving the performance of some biomedical devices, particularly for in vitro bioassays. Some factors have to be paid particular attention in determining the right surface modification which are the types of surface, the methods and chemical solution that being used during the experimentation and also tools for analyzing the results. Improved surface functionalization technologies that provide better non-fouling performance in conjunction with specific attachment chemistries are sought for these applications. Hence, this paper serves as a review for multiple surface treatment methods including PEG grafting, adsorptive chemistries, self-assembled monolayers (SAMs) and plasma treatments.

Optimization of optical fiber splicer for optical communications applications

Optical splicing is regarded as the optical “welding” to combine two or more optical fiber to perform specific functions in modern optical telecommunication systems. In this paper, two crucial parameters in evaluating optical splicing; arc power and arc duration, are optimized for optical fiber splicing. Arc power of 32757 and arc duration of 12000 ms both yielded 0.01 dB splice loss while splicing 9/125 um FC optical fibers. Higher arc power and longer arc duration are found to yield lower splice loss. This paper has laid out optical fiber splicing optimizations and splicing strategies to be used for the development of improved and advanced optical communications applications.

Four wave mixing and cross gain modulation wavelength converters in semiconductor optical amplifier

Wavelength converter is simply a device for converting the injected signal light from one wavelength to another. A simulation wavelength converter made out of a semiconductor optical amplifier and an optical bandpass filter is presented in this paper. The wavelength converter has a simple configuration and allows future photonic integration.