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Electromagnetics and Photonics Commons™
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- Fiber optics (2)
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- Axial flux; Rotor materials; Permanent magnet generator; Halbach array; AFPM generators (1)
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- Civil structural monitoring (1)
- EDF. (1)
- Erbium Ytterbium Fiber Amplifier; Optical Signal Gain; Pump Wavelength Effects; Noise Figure Performance; Rare Earth Doped Fiber (1)
- Erbium doped fiber amplifier (1)
- Fiber Bragg gratings (1)
- Fiber Bragg gratings (FBG) (1)
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- Glass materials; Sol-gel process; Silica; Thin film coatings; Waveguide materials (1)
- Hafnia bismuth-erbium co-doped fiber (1)
- Hermetically sealed transformer (1)
- Hybrid active fibers (1)
- Inductively Coupled Plasma (ICP); Radio Frequency Plasma; Plasma Enhanced Chemical Vapor Deposition (PECVD); Diamond-Like Carbon (DLC) Films; Plasma Diagnostics (1)
- Inductively coupled plasma mass spectrometry (1)
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- Multimode interference (1)
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- Nitrogen gas discharge; Discharge plasma simulation; Electrical field distribution; Space charge effects; Cathode sheath formation (1)
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- Nonlinear optics (1)
Articles 1 - 19 of 19
Full-Text Articles in Electromagnetics and Photonics
Development Of Bragg Fiber Sensor For Corrosion Detection, Cai Hui Tan
Development Of Bragg Fiber Sensor For Corrosion Detection, Cai Hui Tan
Student Works (2020-2029)
Steel corrosion has posed one of the major structural defects in the civil society today. Conventional methods for corrosion monitoring involve high maintenance cost and destructive methods with low accuracy. Recently, Fiber Bragg gratings (FBG) sensor with its high sensitivity in measuring strain and temperature have been widely studied and used in structural health monitoring (SHM). A non-destructive corrosion detection approach based on FBG sensors was developed and tested to monitor corrosion in this research work. The principle of FBG sensing is based on Bragg wavelength shifts that from the corrosion process that induced strain on the FBG due to …
Organic Materials As Saturable Absorber For Pulse Generation At Telecommunication Window, Mohammed Hussein Sameer Salam M.H.
Organic Materials As Saturable Absorber For Pulse Generation At Telecommunication Window, Mohammed Hussein Sameer Salam M.H.
Student Works (2020-2029)
This thesis demonstrates several types of fiber lasers based on newly developed organic materials as saturable absorbers (SAs). We used these SAs in all-fiber based erbium-doped fiber laser (EDFL) ring cavity to produce Q-switched and mode-locked pulses at telecommunication window, at ~ 1560 nm. Three different organic materials were used in this thesis: Bis[2-(4,6-difluorophenyl)pyridinato-C2 ,N](picolinato)iridium(III) (FIrpic), bis(8-hydroxyquinoline)zinc (Znq2) and Tris(8-hydroxyquinoline)aluminum (Alq3). Finding new materials is still one of the defining characteristics of nonlinear optics field, as the rapid development of SAs has provided several new opportunities for nonlinear optics. Throughout this work, organic material showed a very interesting performance in …
Multimode-Interference Based Optical Fiber Sensor For Civil Structures Monitoring, Sue Ping Chew
Multimode-Interference Based Optical Fiber Sensor For Civil Structures Monitoring, Sue Ping Chew
Student Works (2020-2029)
The thesis describes the experimental investigations on the multimode interferencebased fiber sensors using single mode multimode single mode (SMS) and multimode single mode multimode (MSM) structures as a sensing device for structural health monitoring (SHM) applications. Both sensor structures were fabricated, characterized and tested for detecting strain and vibration in civil infrastructures. The proposed SMS structure comprises of a short segment of multimode fiber (MMF), which were fusionspliced by two single mode fibers (SMFs) at both terminals. On the other hand, MSM was fabricated by splicing SMF with MMF at both ends. A new packaging technique for the SMS structure …
Performance Analysis For Single-Stage And Multi-Stage Coreless Axial Flux Permanent Magnet Generator With Different Rotor Structures, Habib Asiful
Student Works (2020-2029)
Axial flux permanent magnet (AFPM) generator is a good candidate for both low and high-speed applications. Compared to radial flux machines, AFPM generators can be easily cascaded for enhanced power/torque while maintaining a fixed machine diameter. To improve power density and reduce cogging torque, some researchers have proposed the removal of iron core in the stator of AFPM machine, giving rise to the concept of coreless AFPM machine. Nevertheless, most of these coreless machines still require back iron on the rotor and/stator to reduce leakage flux. In this project, different rotor structures for single-stage coreless AFPM generators were considered, using …
Wideband And Flat-Gain Optical Amplifier With Hafnia-Bismuth Erbium Co-Doped Fiber, Abduljabbar Al-Azzawi Alabbas Ahmed
Wideband And Flat-Gain Optical Amplifier With Hafnia-Bismuth Erbium Co-Doped Fiber, Abduljabbar Al-Azzawi Alabbas Ahmed
Student Works (2020-2029)
A compact optical amplifier with a flat-gain characteristic is demonstrated using hafnia bismuth-erbium co-doped fiber (HB-EDF) as the gain medium. The HB-EDF was recently fabricated using a modified chemical vapor deposition (MCVD) process in conjunction with solution doping (SD) technique. The fiber has an Erbium ions concentration of 12500 wt. ppm, which was realized due to the co-doping with Hafnium and Aluminum ions. Firstly, the proposed amplifier was investigated for both single and double-pass configurations. It is found that the 0.5m long HB-EDF is the optimum length for the C-band region. For double-pass HB-EDFA, at input signal power of -10 …
Design And Development Of Fiber Bragg Grating Sensor For Detecting Of Hydrogen Gas In Transformer Oil, Mohd Raffi Samsudin
Design And Development Of Fiber Bragg Grating Sensor For Detecting Of Hydrogen Gas In Transformer Oil, Mohd Raffi Samsudin
Student Works (2020-2029)
Hermetically sealed oil-immersed transformers are the key to electricity distribution networks. They are also one of the most expensive facilities in the electricity supply network. Immediate replacement is expected for this type of transformer upon failure because it is directly connected to the customer. Transformer oil acts as insulation, coolant and condition indicator. To date, there is no economical real-time monitoring system available to monitor the transformer oil condition. Therefore, there is a need to develop a cheap, non-intrusive and non-electrical sensor to monitor the health of the transformer by measuring the amount of dissolved hydrogen gas in oil, which …
Design And Simulation Of Silica-On-Silicon Pump/Signal Multiplexer For Hybrid Passive-Active Optical Devices., Alvin Law Wen Pin
Design And Simulation Of Silica-On-Silicon Pump/Signal Multiplexer For Hybrid Passive-Active Optical Devices., Alvin Law Wen Pin
Student Works (2010-2019)
This dissertation describes the design and simulation of silica-on-silicon pump/signal multiplexer for hybrid passive-active optical devices. Uniform symmetric directional couplers and planar Bragg gratings were utilized in this work, forming the essential building blocks in a waveguide amplifier. Several designs in relation to the multiplexers are presented in this work, with the simplest application for the directional coupler as a pump/signal multiplexer. A 980/1550 nm and an 800/1310 nm pump/signal multiplexers for erbium doped and bismuth doped waveguide amplifier, respectively were modeled. These couplers were designed and simulated in Rsoft BeamPROP environment, utilizing 3D Finite Difference Beam Propagation Method (FD-BPM) …
Nonlinear Fiber Lasers Using Bismuth Based Erbium Doper Fiber Amplifier., Sharifeh Shahi
Nonlinear Fiber Lasers Using Bismuth Based Erbium Doper Fiber Amplifier., Sharifeh Shahi
Student Works (2010-2019)
A thorough study on Bismuth-based Erbium-doped fiber (Bi-EDF) is presented for wide-band amplifiers and multi-wavelength fiber laser applications. This fiber allows high Erbium ions concentration to be doped without a significant concentration quenching effect. The high refractive index characteristic in the Bi-EDF has broadened the emission spectrum of Erbium ions to achieve a broader gain spectrum up to extended L-band region compared to normal silica-based Erbium-doped fiber (EDF). The Bi-EDFA performances have been investigated in terms of power conversion efficiency (PCE), quantum conversion efficiency (QCE), gain and noise figure. The highest QCE and PCE for a 215 cm long of …
Reflective And Beam-Through Types Of Fiber Optic Sensor For Displacement Measurement., Walaa Fawzi Al–Masri
Reflective And Beam-Through Types Of Fiber Optic Sensor For Displacement Measurement., Walaa Fawzi Al–Masri
Student Works (2010-2019)
This dissertation proposes and demonstrates fiber-optic displacement sensor (FODS) theoretically and experimentally using the intensity modulation technique to measure a displacement from a probe and target. The sensor uses a multimode plastic bundled fiber as a probe and He-Ne laser as a source. The performance of the sensor is compared for different type of probe and target. For a pair type bundled fiber, both the experimental and theoretical results exhibit the same type of characteristic features. The front slope sensitivities are obtained at 1.71 and 1.0 mW/μm for the theoretical and experimental approaches respectively, while the back slope sensitivities are …
Inductively Coupled Plasma Dry Etching Process On Planar Lightwave Circuit Fabrication., Chuah Khoon Seah
Inductively Coupled Plasma Dry Etching Process On Planar Lightwave Circuit Fabrication., Chuah Khoon Seah
Student Works (2010-2019)
The main objective of this project is to master state-of-the-art techniques and knowledge in silica etching in order to achieve high quality waveguide circuit on Planar Lightwave Circuit devices. Another objective is to optimize the clean room research strength, surface characterization, microscopy techniques and similar semiconductor manufacturing processes.Initially, these processes were conducted with wet etching method that utilized diluted hydrofluoric acid (HF) and buffered oxide etch (BOE). Several problems arising such as mask peel-off, poor sidewall profile and defect waveguide channel during the pattern transfer process due to its’ isotropic nature. Alternatively, dry etching method was conducted via Inductively Coupled …
Optimization Of Inductively Coupled Plasma Dry Etching For Planar Waveguide Fabrication., Lim Weng Hong
Optimization Of Inductively Coupled Plasma Dry Etching For Planar Waveguide Fabrication., Lim Weng Hong
Student Works (2010-2019)
Optimization of the Inductively Coupled Plasma (ICP) dry etching process parameters has been carried out. Seven main etching characteristics were considered in order to produce good etching quality. These characteristics are glass etching rates, selectivity of chromium to glass etching rate, channel side wall roughness, channel side wall vertical profile, channel cleanliness, critical dimension and resolution. Several ICP parameters that are affecting the etching characteristic were optimized in this work. These optimised ICP parameters obtained from this work are ICP power (880 W), bias power (45 W), operating chamber pressure (10 mtorr), reactant gas composition, reactant gas flow rate (35sccm …
Characterization Of An Inductively Coupled Plasma Produced In Argon At 13.56 Mhz., Lim Ai Nuan
Characterization Of An Inductively Coupled Plasma Produced In Argon At 13.56 Mhz., Lim Ai Nuan
Student Works (2010-2019)
The electrical and plasma characteristics of radio frequency (13.56 MHz) inductively coupled argon plasma (RF ICP) were studied in this project. On the electrical breakdown properties, the breakdown voltage has a general appearance of Paschen’s curve and the minimum is achieved at 0.1 mbar. After ignition, two modes of discharge exist, namely, the E mode at low RF power and H mode at high RF power. Mode transition that occurs is accompanied by abrupt changes in both electrical and plasma characteristics. Hysteresis is observed in the mode transitions and has a minimum at 0.1 mbar. The resistance reflected into the …
Nonlinear Fiber Lasers Using Bismuth Based Erbium Doped Fiber Amplifier., Sharifeh Shahi
Nonlinear Fiber Lasers Using Bismuth Based Erbium Doped Fiber Amplifier., Sharifeh Shahi
Student Works (2010-2019)
A thorough study on Bismuth-based Erbium-doped fiber (Bi-EDF) is presented for wide-band amplifiers and multi-wavelength fiber laser applications. This fiber allows high Erbium ions concentration to be doped without a significant concentration quenching effect. The high refractive index characteristic in the Bi-EDF has broadened the emission spectrum of Erbium ions to achieve a broader gain spectrum up to extended L-band region compared to normal silica-based Erbium-doped fiber (EDF). The Bi-EDFA performances have been investigated in terms of power conversion efficiency (PCE), quantum conversion efficiency (QCE), gain and noise figure. The highest QCE and PCE for a 215 cm long of …
The Effect Of Weak Acids Hydrolysis On The Sol-Gel Fabrication Of Silica Thin Film, Abdul Hamid
The Effect Of Weak Acids Hydrolysis On The Sol-Gel Fabrication Of Silica Thin Film, Abdul Hamid
Student Works (2000-2009)
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Modelling Of Space Charge Effects In The Electrical Discharge Of Nitrogen Gas Laser, Chin Yang Chia
Modelling Of Space Charge Effects In The Electrical Discharge Of Nitrogen Gas Laser, Chin Yang Chia
Student Works (2000-2009)
A computer model for the simulation of a nitrogen gas discharge has been built and studied. This model was based on the fluid description of the discharge plasma. The Phoenical SHASTA Flux-Corrected Transport (FCT) algorithm is used for the solution of the fluid equations and its accuracy has been tested. The distribution of the local electrical field was calculated by the Poisson equation. The internal discharge current was calculated by Sato's equation. The motion of the charge particles was taken into account. The electrical discharge behavior was simulated by the circuit equation and solved using the fourth order Runge-Kutta method …
Nitriding Of Titanium By Inductively Coupled Plasma, Abdul Hakim Hashim
Nitriding Of Titanium By Inductively Coupled Plasma, Abdul Hakim Hashim
Student Works (2000-2009)
A RF planar coil inductively coupled plasma syslem (ICP) is used in this project to nitride a commercially pure titanium substrate. The system is powered by a 600 W, 13.56 MHz, 50 Ω RF generator. The impedance matching is achieved by using an air-core step-down transformer and a tunable vacuum capacitor. The electrical discharge characteristics of argon and argon-nitrogen admixture plasmas are investigated. Coil current, ion density and RF power transferred in the plasma at different pressure are studied. Nitriding of titanium using the system is found to be able to produce θ-TiN, ε-Ti2N and α-Ti(N) layers, as confirmed by …
Strained Quantum Well Heterostructure : Modeling And Simulation Of 980 Nm Laser, Yew Mun Hung
Strained Quantum Well Heterostructure : Modeling And Simulation Of 980 Nm Laser, Yew Mun Hung
Student Works (2000-2009)
This thesis concerns the study of a strained quantum well laser diode emitting at wavelength of about 980 nm which is suitable for pumping Er³⁺ doped fiber amplifiers. The concept of a strained quantum well in the design of the active medium of the laser diode is discussed. A model is proposed that incorporates features of the physical structural factors and characteristics of the structure. The theoretical background linked directly to the simulation of the model is to provide calculations and derivations of the optical properties of the modeled structure. Theoretical calculations were made taking into account the variation of …
Diamondlike Carbon Thin Film Deposition Using A Rf Planar Coil Inductively Coupled Plasma System, Wai Soon Liew
Diamondlike Carbon Thin Film Deposition Using A Rf Planar Coil Inductively Coupled Plasma System, Wai Soon Liew
Student Works (2000-2009)
A RF planar coil inductively coupled plasma system (ICPs) is setup for this project. The system is powered by a 13.56MHz, 550W, 500 RF generator. The RF power is transferred to the plasma via a planar induction coil. The impedance matching circuit consists of an air-core step-down transformer and a tunable vacuum capacitor. The typical E-H mode transition which is distinctive to the ICP has been observed in argon plasma, hydrogen plasma and hydrogen-methane admixture plasma. The studies carried out include the observation of intensity of light emission from the plasma, the power transferred at different pressures, the concentration of …
Erbium-Ytterbium Codoped Fiber Amplifiers, Wai Yee Chan
Erbium-Ytterbium Codoped Fiber Amplifiers, Wai Yee Chan
Student Works (2000-2009)
The amplification characteristics of an Erbium/Ytterbium codoped fiber amplifier(EYDFA) pumped in both the 800nm and 980nm pump bands is reported. With -3m long Er-Yb fiber, the 813nm pumped-EYDFA shows small-signal gain exceeding 20dB over a 20nm bandwidth in the l.Sµm region where the peak gain of 38.4dB is achieved at 1535nm. A low noise figure of ~3.6d8 is also achieved at 1550nm. However, it is found that 980nm pumpedEYDF A suffers lower gain due to the effect of nonsaturable absorption by Yb³⁺ ions which causes high pump poWer loss, thus degrades the signal amplification in Er³⁺ system. Compared to the …