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Articles 1 - 23 of 23
Full-Text Articles in Optics
Characterization Of Spatial-Mode Properties In Few-Mode Fiber Bragg Gratings And Its Applications, Muhammad Khairol Annuar Zaini
Characterization Of Spatial-Mode Properties In Few-Mode Fiber Bragg Gratings And Its Applications, Muhammad Khairol Annuar Zaini
Student Works (2020-2029)
Recently, few-mode fiber (FMF) has gained much research attention compared to single mode fiber (SMF) due to its capability to overcome the capacity limit. FMF based fiber sensors have many distinctive advantages such as cost efficiency, great sensitivity, and have the ability to employ the spatial dimension for multi-parameter sensing with discrimination capability. In this work, an analytical model has been proposed to investigate the relationship of the resonant wavelength shift of a few-mode FBG (FMFBG) to the axial stress of the FMF. By applying the proposed model, the axial stress of an FMFs was determined. Besides, the polariscopic technique …
Investigation Of Complex Refractive Index Of Grad Phene Oxide Using Polarisation Response Of Graphene Oxide-Coated Planarizeoptical Waveguide, Soon Xin Gan
Student Works (2020-2029)
Since a single atomic layer of carbon, also as known as graphene is being successfully exfoliated from 3D graphite, intense research on graphene and its derivative begins. Among them, graphene oxide (GO) is considered one of the most prominent candidates in the category of graphene derivatives for the application of electronic, optoelectronic and photonics. However, although GO has been applied in many applications like saturable absorbers of Q-switch laser and optical limiters for eye protection, its intrinsic optical properties especially complex refractive index reported so far still has a large deviation. Also, most of the optical characterization research on GO …
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 …
Quantum Two-Photon Laser In Kerr-Like Medium, Ahmed Mathkoor Faisal Hamood
Quantum Two-Photon Laser In Kerr-Like Medium, Ahmed Mathkoor Faisal Hamood
Student Works (2020-2029)
In this thesis, we studied the Kerr nonlinearity effects on nonclassicality and statistics of the laser field besides the effects of detuning, injection rate, and intensity-dependent coupling (IDC). We developed a quantum theory of light generated from a two-photon laser (TPL) with nonlinear Kerr-like medium in a laser dissipative cavity. The full quantum mechanical approach with the density matrix of the particle-field system is used to derive the TPL master equation based on Scully-Lamb’s quantum theory of laser. Various dynamical operators of interest for the cavity field are calculated analytically and computed numerically. The sophisticated computational program was developed to …
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 …
Pulsed Laser Generation In S+/S Band Using Thulium Fluoride Fiber With Saturable Absorber, Reduan Siti Aisyah
Pulsed Laser Generation In S+/S Band Using Thulium Fluoride Fiber With Saturable Absorber, Reduan Siti Aisyah
Student Works (2020-2029)
Demands on photonic applications has become highly saturated in C-band and L-band region, forcing the needs to work in S band region for the development of alternative data network and photonics technology tools to fulfill the future needs. There are only a few reports on exploiting S band fiber laser operation which mainly used depressed-cladding erbium-doped fiber (DC-EDF) as gain medium. The region covers only ~1480 nm to 1510 nm as mentioned by previous works. Other than that, there is limitation in the selection of rare-element gain medium to generate the emission in S band region. The use of thulium-fluoride …
Validation Of Trap Density Theory In Single Layer Organic Light Emitting Diodes With Tris(8 Hydroxyquinolinato)Aluminium As The Emissive Material, Zaini Mohd Suffian
Validation Of Trap Density Theory In Single Layer Organic Light Emitting Diodes With Tris(8 Hydroxyquinolinato)Aluminium As The Emissive Material, Zaini Mohd Suffian
Student Works (2020-2029)
Organic light-emitting diodes (OLEDs) rapidly evolving as the future of solid-state lighting and display application due to its numerous advantages and features. However, the efficiency, lifetime, and fabrication method still need to be improved. Even in solving efficiency issues in the device, there are many challenges to be addressed and overcome. In theory, charge transport phenomena contribute greatly towards increasing or improving the device efficiency. The magnitude of carrier mobility determines the performance of the device, as it influenced device efficiency. For organic semiconductor such as OLED, space-charge limited current (SCLC) theory was used to determine the mobility of the …
Vanadyl Tetrabutyltetrakis(Dimethylamino) Phthalocyanine Based Thin Films For Organic Sensor And Transistor Applications, Nur Adilah Roslan
Vanadyl Tetrabutyltetrakis(Dimethylamino) Phthalocyanine Based Thin Films For Organic Sensor And Transistor Applications, Nur Adilah Roslan
Student Works (2020-2029)
Organic electronic devices have been successively making progress into the commercial market to substitute conventional inorganic electronic devices. The endeavor to improve the performance displayed by organic semiconductor materials has urged a substantial number of researchers set to seek new materials. Metal phthalocyanines (MPcs), in particular, have garnered much attention due to their enticing benefits viz., cost efficiency, eco-friendly organic material, as well as thermal and chemical stability. Primarily, this study investigated the physical, morphological, optical, and electrical properties of vanadyl 3,10,17,24-tetra-tert-butyl-1,8,15,22-tetrakis(dimethylamino)-29H,31H-phthalocyanine or synonymously known as vanadyl tetrabutyltetrakis (dimethylamino) phthalocyanine (VTP). Subsequently, this study looked into the potential applications of …
Morphological, Structural, And Optical Studies Of Undoped And Doped-Zno Nanostructure., Ramin Yousefi
Morphological, Structural, And Optical Studies Of Undoped And Doped-Zno Nanostructure., Ramin Yousefi
Student Works (2010-2019)
Research concerning one-dimensional nanomaterials has grown tremendously ever since carbon nanotubes were discovered by Iijima (1991), silicon nanowires were grown by Lieber's group (1998), and ZnO nanowires and nanobelts were found by Wang's group from Georgia Tech (Pan et al., 2001). Such researches on one-dimensional structures have been one of the most important branches of science during recent decades. We can now observe the impact of these studies on the technology of one-dimensional materials and also the advanced prospect of developing new technologies. Based on this motivation, this thesis attempts to investigate some unknown properties of ZnO nanostructures as …
Automated Waveguide Alignment And Direct Uv Writing Systems For Integrated Optical Devices Fabrication And Characterization., Tan Chin Chong
Automated Waveguide Alignment And Direct Uv Writing Systems For Integrated Optical Devices Fabrication And Characterization., Tan Chin Chong
Student Works (2010-2019)
This dissertation reports the studies on the development of waveguide alignment techniques as well as the UV writing coding structures for optical circuitries through a programming platform, LabVIEW. In the first part of the work, 1-by-4 silica splitter was pigtailed with a single mode fiber which placed on a stepper motorized stage. The developed alignment techniques are image analysis for waveguide alignment, initial light seeking from interference fringes, manual alignment of launch fiber for waveguide’s input, and peak power detection. These waveguide alignment techniques covered from the search of input channel within waveguide to the performance test. While, in the …
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 …
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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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 …
Optical Coherent Communication System Using Phase Shift Keying, Syed Javaid Iqbal
Optical Coherent Communication System Using Phase Shift Keying, Syed Javaid Iqbal
Student Works (2000-2009)
This thesis presents the experimental study and design of a coherent communication system by using phase shift keying (PSK). Systems are designed by using all passive elements, which make the system very easy to operate, and less maintenance is required. All the PSK designs are based on a single light source. In this thesis there are five different types of PSK with a single light source communication systems are designed. All designs are experimentally tested in free space. The systems are • All optical two-channel PSK communication system, by using single light source, "All optical single channel, two-way PSK communication, …
Fabrication And Application Of Fiber Bragg Grating, Wadi Harun Sulaiman
Fabrication And Application Of Fiber Bragg Grating, Wadi Harun Sulaiman
Student Works (2000-2009)
This dissertation presents the fabrication, characterization and application of short period fiber Bragg grating (FBG). The FBG is inscribed on high germania boron co-doped optical fiber by phase mask method with a 244nm continuous wave frequency doubled Argon ion laser as a laser source. The FBGs with reflectivity ranging from 98 -99.9%, bandwidth of 0.3 ~ 0.9nm and center wavelength of 1552.5 - 1553.5nm have been fabricated successfully with this method. The time taken for these inscriptions are within 10 to 30 minutes depending on alignment. The fabricated FBGs are characterized using both fiber amplifier (broadband source) and tunable laser …
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 …
Optimisation Of Transverse Arc Array Laser, Albert Kok Foo Ng
Optimisation Of Transverse Arc Array Laser, Albert Kok Foo Ng
Student Works (2000-2009)
A novel discharge scheme is proposed for the pumping of short wavelen,gth lasers. This scheme had been tested to produce fast current pulse and a 5 kA current in 60 nsec is obtained. Lasing action has been observed by using nitrogen gas. The laser line is 337 nm from the strong transitions of nitrogen molecules. The new discharge scheme is based on the concept of an arc array amplifier. It essentially consists of 48 pairs of electrodes which are lined up to form an array of arc discharge. Its electrical circuitry allows each pair of the electrodes to be decoupled …
Investigations Of Transverse Arc Array Laser Action In Nitrogen Gas, Kee Siang Goh
Investigations Of Transverse Arc Array Laser Action In Nitrogen Gas, Kee Siang Goh
Student Works (2000-2009)
In almost all pulsed gas lasers, transverse electrical discharge is employed in the excitation of the atoms or molecules. These lasers normally employ discharge across a pair of common electrodes to provide large volume and uniform glow discharge. The scaling of output power in such lasers is obtained by increasing the volume of the discharge and also the pressure of the discharge gas. For this reason. the energy coupled into the discharge channel is kept low enough to avoid arcing. Under these circumstances, the electron temperature of such uniform glow discharge is not sufficient to produce excitation of VUV or …
Development Of Multiple Channels Edf Lasers, Muhammad Zamzuri Abdul Kadir
Development Of Multiple Channels Edf Lasers, Muhammad Zamzuri Abdul Kadir
Student Works (2000-2009)
This thesis presents the research work carried out on the development and analysis of single wavelength EDFL and multiple wavelength EDFL. Two types of single wavelength EDF ring laser were studied namely a fixed signal wavelength system and a tuneable signal wavelength system. However, emphasis was given to the first case. The analyses made, were based on the following parameters: pump and signal stability, pump power, reflectivity, EDF length and cavity loss. The influence of each cavity component such as isolator, polarisation controller, attenuator and tuneable filter were also investigated and reported here. Only one type of multiple wavelength EDFL …
Digital Holography And Application In Laser Metrology, Thian Khok Yong
Digital Holography And Application In Laser Metrology, Thian Khok Yong
Student Works (2000-2009)
A digital holography system has been developed in this study. The object is recorded and the hologram is stored electronically with a charged-couple-device (CCD) camera without any focusing optics. The reconstruction of the digitally sampled hologram is done numerically with a computer. The algorithm and software for numerical reconstruction, which consists in a numerical realization of the Fresnel-Kirchhoff diffraction integral, are designed and implemented with twodimensional and three-dimensional simple objects. The characteristics of the system have been studied. For the CCD camera (768x494 pixels) been used with spatial resolution of about I 00 lines/mm, the angle between reference and object …