COMPARATIVE STUDY ON SINGLE- AND DOUBLE-PASS CONFIGURATIONS FOR SERIAL DUAL-STAGE HIGH CONCENTRATION EDFA

A comparative study on a single- and double-pass configurations for Erbium-doped fiber amplifier (EDFA) are demonstrated using a gain media of high concentration Silica-based erbium doped fiber (EDF). The amplifier has two stages comprising a 1.5 m and 9 m long EDF optimized for C-band and L-band operations respectively, in a single-pass and double-pass configuration s. The CFBG is used at the end of EDF stage to allow a double propagation of signal and thus increases the attainable gain in both C- and L-band spectra. At an input signal power of -30 dBm, a flat gain of 22 dB is achieved with a gain variation of ±3 dB within a wide wavelength range from 1530 to 1600nm (C- and L-band) in double-pass configurations. The corresponding noise figure varies from 4 to 8 dB within this wavelength region. The flat gains for single-pass configuration only amplify within 1555 nm to 1600 nm (L-band)

THREE BIT SUBTRACTION CIRCUIT VIA FIELD PROGRAMMABLE

This project is about to design the software and hardware simulator for a Three Bit subtraction Circuit via Field Programmable Gate Array (FPGA). The three bit subtraction circuits are involved in performing the subtraction for each bit by performs operation the arithmetic and logic unit, called the Arithmetic Logic Unit (ALU). All this operation is to be displayed at seven segment using FPGA board by using Verilog language. A FPGA is a semiconductor device containing programmable logic components called "logic blocks", and programmable interconnects. Logic blocks can be programmed to perform the function of basic logic gates such as AND, and XOR, or more complex combinational functions such as decoders or simple mathematical functions such as additional, subtraction, multiplication, and divisions (+, -, x, ÷). In conclusion, three bit subtraction circuit via FPGA has been successfully designed and developed. In order to have a complete system that is design by our own, one of the recommendation to enhance the possibility of this thesis is to develop the hardware equip with wireless technology

Examination of adulterated coconut oil by fiber optics displacement sensor using lateral offset approach

A single-mode fiber (SMF) sensor for detecting coconut oil adulteration is proposed. Coconut oil is commonly used in cooking but health problems are caused by its adulteration. The lateral offset approach to the SMF-SMF displacement sensor was employed in this experiment to analyze the sensing responses of adulterant concentrations in coconut oil. The offset distances of the sensing probe were set at 6.47 µm, 11.57 µm, and 14.64 µm. Pure coconut oil, paraffin oil, and palm oil have an initial refractive index of 1.4481, 1.4585, and 1.4634, respectively. Upon completion, the highest sensitivity was observed at a lateral offset distance of 14.64 µm. These values were 0.286 dBm/mol for palm oil detection and 0.045 dBm/mol for paraffin oil detection. The findings of these experiments also showed that the larger the offset distance, the greater the sensitivity of the fiber sensor

Modelling of Swarm Communication

Swarm communication is a communication process of sending data within a certain area via agents.. Data will be sent to all the agents in this process. This is also closely related to the way of broadcasting via “short communication” as a way to find out the data among their agents. This field involved an in -depth study of the behaviour of the agents and by using a homogeneous approach, inspect the process of sending data. This includes investigation of independence of agents and the characteristics of sending and receiving data for a random process in a swarm. In this paper, techniques useful for swarm implemented bit-communication behaviour will be presented. There are two approaches that are used to send and receive signals. The reverse approach is where data can be resend to the sender for the next cycle, where the program randomly selects the nearest agents t o send data to. While for the nonreversing approach data is not able to return to the sender in the previous cycle. The non -reversing approach can improve system performance and efficiency. This paper presents the development of a swarm communication mode l and how it can be used to illustrate the communication process

Recent progress of tapered optical fiber for biosensing applications

The development of reliable, lightweight, and effective sensors is a vital step in effectively monitoring critical parameter changes. This review focuses on the utilization of tapered optical fiber as a material sensing platform. The fundamental concept of the tapered fiber sensor is based on the interaction of strong evanescent waves caused by the fiber's dimensional change. The primary goal of this review is to explore the potential of tapered optical fiber for biosensing applications. A number of tapered optical fiber configurations and operations have been reviewed in order to propose appropriate optical sensor designs for biosensing applications. Hence, this analysis could serve as a benchmark for a more thorough study of biosensing device development

ZnO Nanorods Coated Microfiber Loop Resonator For Relative Humidity Sensing

This paper reported a new humidity sensor, employing microfiber loop resonator (MLR) coated with Zinc Oxide (ZnO) as a probe. The MLR was constructed from a silica tapered fiber with a waist diameter of 7 µm, which was prepared using flame brushing technique. The self-touching loop was coated by ZnO using sol–gel method. A significant response to humidity changes from 35%RH to 85%RH was observed due to the changeable refractive index of the ZnO coating material which modified the light propagation at the output of the MLR. The result shows that the sensitivity of the proposed sensor increases by a factor of 2 as compared to the uncoated MLR. The output power of the ZnO coated MLR drops linearly from −29.3 dBm to −43 dBm when relative humidity increases from 35%RH to 85%RH. The linearity and resolution of the ZnO coated MLR also outperformed the uncoated MLR with 99.4% and 0.013%RH respectively

Agarose gel coated glass substrate for formaldehyde sensing application

This paper demonstrated an intensity modulation detection system employing agarose gel coated on the glass substrate for formaldehyde sensing application. The objectives of this work is to develop a simple and low cost formaldehyde sensor using commercially available microscope glass substrate, coating material and data acquisition unit. The glass substrate was coated with agarose gel using low temperature synthesis method which has superiority in term of high porosity and capable to absorb molecule around it. The formaldehyde detection is based on the change in refractive index (RI) of the agarose gel as a coating material. The RI change of the coating materials will modulate the output light intensity when the concentration level of the formaldehyde varies. This is due to the intensity of the light weakening by absorption and scattering when light propagated through the sensing material. A significant response to formaldehyde concentrations was observed with the output voltage reduced linearly from 1.1V to 0.4V. The sensitivity and the linearity of the proposed sensor improve by a factor of 1.02 and 1.03 respectively as compared to uncoated glass substrate. Moreover, it performs better in term of stability, hysteresis and time response. The proposed formaldehyde sensor avoid utilization of costly optical sensor setup based on laser source which are not feasible for large scale production. Based on the experiment results, the proposed sensor has a good potential as a formaldehyde sensor which is essential for food, health and environmental secto

Formaldehyde sensing using tapered u-shape plastic optical fiber coated with zinc oxide nanorods

Continuous exposure to formaldehyde may cause injury to the central nervous, respiratory, blood, and immunological systems. Tapered U-shape plastic optical fiber (POF) coated with zinc oxide nanorods was evaluated at wavelength of 645 nm for formaldehyde vapor sensing within a concentration range from 5% to 20%. The tapered POF with 500 µm waist diameter was prepared using chemical etching technique. Zinc oxide nanorods were synthesized using hydrothermal method and growth for 12 hours on the tapered POF. The proposed sensor exhibited a good response to formaldehyde concentration ranging from 5% to 20% with sensitivity and linearity measured to be 0.00543V/% and 98.58%, respectively. Excellent measurement stability was observed when the concentrations from 5% and above are maintain over a 600 second period. Highest difference voltage was produced by 0.0958V due to the more scattering effect of ZnO nanorods at 20% of formaldehyde concentration. This proposed sensor might be also used to detect air pollution produced not just by formaldehyde vapor, but also by other dangerous or poisonous vapors or gases

ZnO nanorods coated tapered u-shape plastic optical fiber for relative humidity detection

A relative humidity sensor was fabricated by exploiting an evanescent wave (EW) on a U-bent tapered plastic optical fiber (POF) coated with zinc oxide (ZnO) nanorods. The POF was tapered manually using a polishing method to a diameter of 0.5 mm, a length of 5 cm, and a radius of 5 cm. ZnO nanorods were synthesized using a hydrothermal method and grown on the POF by a seeding process for 12 h. A significant response of the sensor was observed when the sensor was exposed to 35 to 90%RH due to the intense chemisorption process and changeable relative index in the POF. The sensitivity and resolution of the sensor have been improved by factors of 1.23 and 2.18, respectively, compared to the conventional tapered POF sensor without ZnO coating. Besides, the ZnO-coated sensor also exhibited better repeatability properties in terms of output voltage when exposed to 35 to 90%RH for three repeated measurements. The obtained results revealed that the proposed new POF sensor has an excellent sensing performance as an RH sensor in terms of sensitivity, repeatability, and stability propertie