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Articles 1 - 11 of 11
Full-Text Articles in Engineering
Characterization Of Turn-On Time Delay In A Fiber Grating Fabry-Perot Lasers, Faisal Rafiq Mahamd Adikan
Characterization Of Turn-On Time Delay In A Fiber Grating Fabry-Perot Lasers, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
In this paper, turn-on time delay characteristics of a fiber grating Fabry-Perot (FGFP) laser are numerically investigated by considering all the carrier recombination rate (CRR) R(N) coefficients (nonradiative, A(nr); radiative, B; and Auger coefficient, C). The results show that the turn-on time delay significantly reduces by increasing the injection current (I-inj) and/or the initial value of carrier density (N-i). Meanwhile, the turn-on time delay increases by increasing the CRR coefficients. However, its effect can be minimized by increasing I-inj and/or N-i. In addition, the turn-on time delay can be reduced by increasing the external optical feedback (OFB) level. Moreover, it …
Fabrication Of A Multimode Interference Device In A Low-Loss Flat-Fiber Platform Using Physical Micromachining Technique, Faisal Rafiq Mahamd Adikan
Fabrication Of A Multimode Interference Device In A Low-Loss Flat-Fiber Platform Using Physical Micromachining Technique, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
A physical micromachining technique is demonstrated in a low-loss flat-fiber substrate to fabricate a multimode interference (MMI) device. The flat-fiber substrate is a low-index-contrast material; however, by making use of two physically micromachined trenches, lateral confinement is achieved providing high index contrast for the MMI region. A 1 x 3 MMI device exhibiting 1.89 dB of excess loss has been demonstrated.
Efficient, Wide Angle, Structure Tuned 1 X 3 Photonic Crystal Power Splitter At 1550 Nm For Triple Play Applications, Faisal Rafiq Mahamd Adikan
Efficient, Wide Angle, Structure Tuned 1 X 3 Photonic Crystal Power Splitter At 1550 Nm For Triple Play Applications, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
We propose a wide angle, efficient and low loss 1 x 3 power splitter based on triangular lattice air holes silicon slab Photonic Crystal (PhC). Desired power splitting ratio was achieved by altering the structure at the junction area of the power splitter. Simulation results obtained using 2-D finite difference time domain method show that for TE polarization incident signal, the power is distributed almost equally with total normalized transmission of 99.74% and negligible reflection loss at the 1550 nm optical operating wavelength. In addition, the power splitter can operate at 1388 nm and 1470 nm optical wavelengths.
Infrared Study Of Er3+/Yb3+ Co-Doped Geo2-Pbo-Bi2o3 Glass, Faisal Rafiq Mahamd Adikan
Infrared Study Of Er3+/Yb3+ Co-Doped Geo2-Pbo-Bi2o3 Glass, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
Heavy metal oxide glasses, containing bismuth and/or lead in their glass structure are new alternatives for rare eart (RE) doped hosts. Hence, the study of the structure of these vitreous systems is of great interest for science and technology. In this research work, GeO2-PbO-Bi2O3 glass host doped with Er3+/Yb3+ ions was synthesized by a conventional melt quenching method. The Fourier transform infrared (FTIR) results showed that PbO and Bi2O3 participate with PbO4 tetragonal pyramids and strongly distort BiO6 octahedral units in the glass network, which subsequently act as modifiers in glass structure. These results also confirmed the existence of both …
Millimeter Wave Carrier Generation Based On A Double-Brillouin-Frequency Spaced Fiber Laser, Faisal Rafiq Mahamd Adikan
Millimeter Wave Carrier Generation Based On A Double-Brillouin-Frequency Spaced Fiber Laser, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
An all-optical generation of a millimeter wave carrier from a multiwavelength Brillouin-erbium fiber laser is presented. Four-channel output with spacing of about 21.5 GHz is generated from the fiber laser by controlling the gain in the cavity. A dual-wavelength signal with spacing correspondent to six orders of Brillouin frequency shift is obtained by suppressing the two channels at the middle. Heterodyning these signals at the high-speed photodetector produces a millimeter wave carrier at 64.17 GHz. Temperature dependence characteristic of Brillouin frequency shift realize the flexibility of generated millimeter wave frequency to be tuned at 6.6 MHz/ degrees C. (C) 2012 …
Rayleigh-Based Raman Fiber Laser With Passive Erbium-Doped Fiber For Secondary Pumping Effect In Remote L-Band Erbium-Doped Fiber Amplifier, Faisal Rafiq Mahamd Adikan
Rayleigh-Based Raman Fiber Laser With Passive Erbium-Doped Fiber For Secondary Pumping Effect In Remote L-Band Erbium-Doped Fiber Amplifier, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
This work focuses on a secondary pumping scheme for remote L-band erbium-doped fiber amplifier (R-EDFA) generated by integrating Rayleigh-based ultralong Raman fiber laser (ULRFL) with a section of passive erbium-doped fiber (EDF). A selective wavelength reflector combined with Rayleigh feedback in the transmission span forms the ULRFL cavity while the passive EDF deployed at the end of the span converts the ULRFL into a secondary C-band pump. Optimum ULRFL wavelength is determined by tuning the selective wavelength reflector across the C-band region. Combination of R-EDFA gain, Raman amplification, and passive EDF provides gain improvement as high as 15.5 dB over …
Laser Parameter Variations In A Rayleigh Scattering-Based Raman Fiber Laser With Single Fiber Bragg Grating Reflector, Faisal Rafiq Mahamd Adikan
Laser Parameter Variations In A Rayleigh Scattering-Based Raman Fiber Laser With Single Fiber Bragg Grating Reflector, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
The work presented in this paper details the changes in continuous-wave laser characteristics that were affected by the orientation of pumping separation. The Raman laser was constructed in forward and backward pumping schemes with respect to the 1553.3-nm fiber Bragg grating location. The laser cavity was formed by the induction of Rayleigh backscattering effects in the 51-km fiber length that served as a virtual mirror. From the results obtained, it can be concluded that low threshold operation around 788 mW was satisfied at a coupling ratio of 0 (forward pumping scheme). Moreover, the best output power attainment of 220 mW …
Spreading Profile Of Evaporative Liquid Drops In Thin Porous Layer, Faisal Rafiq Mahamd Adikan
Spreading Profile Of Evaporative Liquid Drops In Thin Porous Layer, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
Spreading of evaporative liquid drops in a thin porous layer has been studied. The entire spreading process can be divided into three distinct phases according to the change of the wetted porous region size. The first phase is characterized by the expansion of the wetted porous region and shrinking of the liquid drop. Contact line pinning is observed in the wetted porous region in the second phase even with the liquid drop totally absorbed into the porous layer. The third phase sees the shrinkage of the wetted porous region until it is not observable. Based on these observations, a model …
Analytical Analysis Of Second-Order Stokes Wave In Brillouin Ring Fiber Laser, Faisal Rafiq Mahamd Adikan
Analytical Analysis Of Second-Order Stokes Wave In Brillouin Ring Fiber Laser, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
This paper details a theoretical modeling of Brillouin ring fiber laser which incorporates the interaction between multiple Brillouin Stokes signals. The ring cavity was pumped at several Brillouin pump (BP) powers and the output was measured through an optical coupler with various coupling ratios. The first-order Brillouin Stokes signal was saturated with the presence of the second-order Stokes signal in the cavity as a result of energy transfer between them. The outcome of the study found that the optimum point for the first-order Stokes wave performance is at laser power reduction of 10%. Resultantly, at the optimum output coupling ratio …
Dual-Phase Sensing For Early Detection Of Prepreg Structural Failures Via Etched Cladding Bragg Grating, Faisal Rafiq Mahamd Adikan
Dual-Phase Sensing For Early Detection Of Prepreg Structural Failures Via Etched Cladding Bragg Grating, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
A dual-phase optical fiber-based sensor for early detection against prepreg structural failures is proposed and successfully demonstrated. The sensor consists of an etched fiber Bragg grating (FBG) mounted onto an aluminium plate. The sensor is tested using a simple pressure and petrochemical test rig. By observing the shift of the reflected wavelength of the FBG sensor we can simultaneously detect two parameters: (i) pressure and (ii) petrochemical. The experimental results show the potential of using the FBG sensor for early detection of submarine oil pipe leaking. (C) 2011 Elsevier B.V. All rights reserved.
Analytical Study Of Nonlinear Phase Shift Through Stimulated Brillouin Scattering In Single Mode Fiber With The Pump Power Recycling Technique, Faisal Rafiq Mahamd Adikan
Analytical Study Of Nonlinear Phase Shift Through Stimulated Brillouin Scattering In Single Mode Fiber With The Pump Power Recycling Technique, Faisal Rafiq Mahamd Adikan
Faisal Rafiq Mahamd Adikan
We present a theoretical study of nonlinear phase shift through stimulated Brillouin scattering in single mode optical fiber. Analytical expressions describing the nonlinear phase shift for the pump and Stokes waves in the pump power recycling technique have been derived. The dependence of the nonlinear phase shift on the optical fiber length, the reflectivity of the optical mirror and the frequency detuning coefficient have been analyzed for different input pump power values. We found that with the recycling pump technique, the nonlinear phase shift due to stimulated Brillouin scattering reduced to less than 0.1 rad for 5 km optical fiber …