Muddassir Iqbal | Air University, Islamabad (original) (raw)
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Papers by Muddassir Iqbal
Microwave and Optical Technology Letters, 2022
Mode‐locking is an increased focus area due to the augmented requirement of ultra‐short and high‐... more Mode‐locking is an increased focus area due to the augmented requirement of ultra‐short and high‐intensity optical pulses for varied applications. Tunable mode‐locked lasers capable of operating in the infrared range at high repetition frequency brought innovative opportunities for insensitive and accurate laser surgery. As one important application of optical pulse propagation in an optical fiber, we have discussed a dual‐ring hybrid mode‐locked fiber laser using modulator, and saturable absorber. The active mechanism, saturable absorber, and the nonlinear optical loop mirror result in an output with a peak power of 16 dBm, and 80 fs full‐width at half‐maximum with a high duty cycle. It occupies a small space and is easy to achieve miniaturization and intensification; the laser output can be adjusted by varying multiple parameters such as pump, input, doped fiber length, modulator (including modulation signal), saturable absorber, and other devices.
intechopen.com
In this chapter we will discuss about slot optical waveguides analysis using finite difference ti... more In this chapter we will discuss about slot optical waveguides analysis using finite difference time domain (FDTD) algorithm. SOI slot optical waveguides invented in 2004, by Lipson at Cornell nanophotonics center [1], and experimentally demonstrated by them in forming ...
Optik - International Journal for Light and Electron Optics, 2017
Nonlinear-optic (NLO) effects provide many device functions such as wavelength conversion and sig... more Nonlinear-optic (NLO) effects provide many device functions such as wavelength conversion and signal processing. The use of waveguides allows the implementation of efficient and compact devices. The importance of exploring nonlinear effects in Silicon-on-Insulator (SOI) slot optical waveguides is discernible from the facts that, it is CMOS technology compatible, thus ensuring low-cost large-scale integration, moreover, this structure of optical waveguides mingle the advantages of both silicon and silica to explore the promising nonlinear interactions of light in the waveguides, such as rare-earth material doping to provide optical gain. In current research work, we have optimized nonlinear parameter (γ) of the basic SOI slot optical waveguide by reducing the effective area (Aeff). The effective area has been reduced by using Photonic Crystal Fiber (PCF) type cladding; where enough evidence is available that, SOI slot optical waveguide can be fabricated in a PCF type cladding. Wavelength dependent propagation constant values of slot optical waveguide are dominant over the band-gap effect (in case of PCF type cladding). Novelty lies in reducing the effective area (Aeff) by a considerable amount, with respect to already established results. The results, besides opening further venues for researchers to find out nonlinear optimization techniques of slot optical waveguide structures can also help in enhancing lab on chip circuits, where in-built optical source is mandatory.
Microwave and Optical Technology Letters
Abstract: Pulse propagation in a birefringent medium carries due weightage and importance in pass... more Abstract: Pulse propagation in a birefringent medium carries due weightage and importance in passive modelocking of fiber lasers. We have carried out study of nonlinear effects in birefringent medium by simulating pulse propagation using adaptive step size method, which is globally an efficient algorithm for solving Schrodinger type equations using split step Fourier method. Nonlinear optical loop mirror was realized and it was revealed that the results can be used in forming a figure of eight fiber laser using NOLM, where NOLM behaves like a fast saturable absorber. Novelty lies in producing accurate results using adaptive step size method.
Pulse propagation in a birefringent medium carries due weightage and importance in passive modelo... more Pulse propagation in a birefringent medium carries due weightage and importance in passive modelocking of fiber lasers. We have carried out study of nonlinear effects in birefringent medium by simulating pulse propagation using adaptive step size method, which is globally an efficient algorithm for solving Schrodinger type equations using split step Fourier method. Nonlinear optical loop mirror was realized and it was revealed that the results can be used in forming a figure of eight fiber laser using NOLM, where NOLM behaves like a fast saturable absorber. Novelty lies in producing accurate results using adaptive step size method. Index Terms: Non-linear Schrodinger equation (NLSE), Self Phase modulation (SPM), cross phase modulation (XPM), kerr non-linearity, Symmetrized split step Fourier method (SSSFM), Nonlinear Optical Loop Mirror (NOLM).
The advent of optical waveguides with a unique geometry, where the central part is of low refract... more The advent of optical waveguides with a unique geometry, where the central part is of low refractive index as compared to the material on the sides, here-after named as a slot(s) guarded by slabs with unique properties of light confinement opened new opportunities for lab-on-chip circuits. Apart from passive dispersion compensator circuits (proposed by us for the first time), active optical circuits have also been designed (by other researchers). In this research we are in a quest to harvest the benefits of Silicon-on-Insulator (SOI) slot optical waveguides in the area of photo-voltaic solar power generation; earlier we have proposed simple and easy to implement periodic/ basic multiple air cladded slot structures. In this research work, we have implemented buried SOI slot optical waveguides; the solar spectrum incarceration with our earlier research work is also being compared. With the advancement in nano-technologies, it is never a problem to implement nanometers wide optical wav...
Growing demand of communication networks requires ultra-short pulses. Ultra-short pulses can guar... more Growing demand of communication networks requires ultra-short pulses. Ultra-short pulses can guarantee high data transfer and power. Fiber lasers, which are actively or passively mode-locked to generate ultra-short pulses, are termed as Mode locked fiber lasers. There are a number of methods available for mode-locking of lasers. We have discussed most of them in this paper. At the end a model of actively mode-locked fiber ring laser is simulated.
Brazilian Journal of Physics
Current Nanoscience
Background: Among various chalcogenides, GeSbSe shows a good transmittance in the visible, NIR an... more Background: Among various chalcogenides, GeSbSe shows a good transmittance in the visible, NIR and, midIR spectrum from 1-20 μm and also demonstrates excellent moldability. Objective: In current work, we have characterized GeSbSe glass for use in sensor mechanism and for adaptive polarization control. Methods: After analysing an earlier work regarding GeSbSe based Silicon on insulator optical waveguide, we implemented GeSbSe in a low refractive index slot region of SOI slot optical waveguide. Change in waveguide geometry can cause a shift in the dispersion profile, but a relatively distinct pattern has been observed. T-slot waveguide structure has also been analysed, where GeSbSe has been implemented in low refractive index slot regions with the Graphene layer beneath the horizontal slot region for enhancement in tailoring ability of the birefringence parameters. Results: Literature review led to the presence of absorption resonance wavelength in SOI slot optical waveguide with our ...
IEEE Journal of Selected Topics in Quantum Electronics
2016 19th International Multi-Topic Conference (INMIC), 2016
2009 International Conference on Optical Instruments and Technology: Advanced Sensor Technologies and Applications, 2009
2009 International Conference on Optical Instruments and Technology: Advanced Sensor Technologies and Applications, 2009
Optics Communications, 2008
2008 International Conference on Microwave and Millimeter Wave Technology, 2008
2006 International Conference on Emerging Technologies, 2006
Asia Communications and Photonics Conference and Exhibition, 2009
Microwave and Optical Technology Letters, 2022
Mode‐locking is an increased focus area due to the augmented requirement of ultra‐short and high‐... more Mode‐locking is an increased focus area due to the augmented requirement of ultra‐short and high‐intensity optical pulses for varied applications. Tunable mode‐locked lasers capable of operating in the infrared range at high repetition frequency brought innovative opportunities for insensitive and accurate laser surgery. As one important application of optical pulse propagation in an optical fiber, we have discussed a dual‐ring hybrid mode‐locked fiber laser using modulator, and saturable absorber. The active mechanism, saturable absorber, and the nonlinear optical loop mirror result in an output with a peak power of 16 dBm, and 80 fs full‐width at half‐maximum with a high duty cycle. It occupies a small space and is easy to achieve miniaturization and intensification; the laser output can be adjusted by varying multiple parameters such as pump, input, doped fiber length, modulator (including modulation signal), saturable absorber, and other devices.
intechopen.com
In this chapter we will discuss about slot optical waveguides analysis using finite difference ti... more In this chapter we will discuss about slot optical waveguides analysis using finite difference time domain (FDTD) algorithm. SOI slot optical waveguides invented in 2004, by Lipson at Cornell nanophotonics center [1], and experimentally demonstrated by them in forming ...
Optik - International Journal for Light and Electron Optics, 2017
Nonlinear-optic (NLO) effects provide many device functions such as wavelength conversion and sig... more Nonlinear-optic (NLO) effects provide many device functions such as wavelength conversion and signal processing. The use of waveguides allows the implementation of efficient and compact devices. The importance of exploring nonlinear effects in Silicon-on-Insulator (SOI) slot optical waveguides is discernible from the facts that, it is CMOS technology compatible, thus ensuring low-cost large-scale integration, moreover, this structure of optical waveguides mingle the advantages of both silicon and silica to explore the promising nonlinear interactions of light in the waveguides, such as rare-earth material doping to provide optical gain. In current research work, we have optimized nonlinear parameter (γ) of the basic SOI slot optical waveguide by reducing the effective area (Aeff). The effective area has been reduced by using Photonic Crystal Fiber (PCF) type cladding; where enough evidence is available that, SOI slot optical waveguide can be fabricated in a PCF type cladding. Wavelength dependent propagation constant values of slot optical waveguide are dominant over the band-gap effect (in case of PCF type cladding). Novelty lies in reducing the effective area (Aeff) by a considerable amount, with respect to already established results. The results, besides opening further venues for researchers to find out nonlinear optimization techniques of slot optical waveguide structures can also help in enhancing lab on chip circuits, where in-built optical source is mandatory.
Microwave and Optical Technology Letters
Abstract: Pulse propagation in a birefringent medium carries due weightage and importance in pass... more Abstract: Pulse propagation in a birefringent medium carries due weightage and importance in passive modelocking of fiber lasers. We have carried out study of nonlinear effects in birefringent medium by simulating pulse propagation using adaptive step size method, which is globally an efficient algorithm for solving Schrodinger type equations using split step Fourier method. Nonlinear optical loop mirror was realized and it was revealed that the results can be used in forming a figure of eight fiber laser using NOLM, where NOLM behaves like a fast saturable absorber. Novelty lies in producing accurate results using adaptive step size method.
Pulse propagation in a birefringent medium carries due weightage and importance in passive modelo... more Pulse propagation in a birefringent medium carries due weightage and importance in passive modelocking of fiber lasers. We have carried out study of nonlinear effects in birefringent medium by simulating pulse propagation using adaptive step size method, which is globally an efficient algorithm for solving Schrodinger type equations using split step Fourier method. Nonlinear optical loop mirror was realized and it was revealed that the results can be used in forming a figure of eight fiber laser using NOLM, where NOLM behaves like a fast saturable absorber. Novelty lies in producing accurate results using adaptive step size method. Index Terms: Non-linear Schrodinger equation (NLSE), Self Phase modulation (SPM), cross phase modulation (XPM), kerr non-linearity, Symmetrized split step Fourier method (SSSFM), Nonlinear Optical Loop Mirror (NOLM).
The advent of optical waveguides with a unique geometry, where the central part is of low refract... more The advent of optical waveguides with a unique geometry, where the central part is of low refractive index as compared to the material on the sides, here-after named as a slot(s) guarded by slabs with unique properties of light confinement opened new opportunities for lab-on-chip circuits. Apart from passive dispersion compensator circuits (proposed by us for the first time), active optical circuits have also been designed (by other researchers). In this research we are in a quest to harvest the benefits of Silicon-on-Insulator (SOI) slot optical waveguides in the area of photo-voltaic solar power generation; earlier we have proposed simple and easy to implement periodic/ basic multiple air cladded slot structures. In this research work, we have implemented buried SOI slot optical waveguides; the solar spectrum incarceration with our earlier research work is also being compared. With the advancement in nano-technologies, it is never a problem to implement nanometers wide optical wav...
Growing demand of communication networks requires ultra-short pulses. Ultra-short pulses can guar... more Growing demand of communication networks requires ultra-short pulses. Ultra-short pulses can guarantee high data transfer and power. Fiber lasers, which are actively or passively mode-locked to generate ultra-short pulses, are termed as Mode locked fiber lasers. There are a number of methods available for mode-locking of lasers. We have discussed most of them in this paper. At the end a model of actively mode-locked fiber ring laser is simulated.
Brazilian Journal of Physics
Current Nanoscience
Background: Among various chalcogenides, GeSbSe shows a good transmittance in the visible, NIR an... more Background: Among various chalcogenides, GeSbSe shows a good transmittance in the visible, NIR and, midIR spectrum from 1-20 μm and also demonstrates excellent moldability. Objective: In current work, we have characterized GeSbSe glass for use in sensor mechanism and for adaptive polarization control. Methods: After analysing an earlier work regarding GeSbSe based Silicon on insulator optical waveguide, we implemented GeSbSe in a low refractive index slot region of SOI slot optical waveguide. Change in waveguide geometry can cause a shift in the dispersion profile, but a relatively distinct pattern has been observed. T-slot waveguide structure has also been analysed, where GeSbSe has been implemented in low refractive index slot regions with the Graphene layer beneath the horizontal slot region for enhancement in tailoring ability of the birefringence parameters. Results: Literature review led to the presence of absorption resonance wavelength in SOI slot optical waveguide with our ...
IEEE Journal of Selected Topics in Quantum Electronics
2016 19th International Multi-Topic Conference (INMIC), 2016
2009 International Conference on Optical Instruments and Technology: Advanced Sensor Technologies and Applications, 2009
2009 International Conference on Optical Instruments and Technology: Advanced Sensor Technologies and Applications, 2009
Optics Communications, 2008
2008 International Conference on Microwave and Millimeter Wave Technology, 2008
2006 International Conference on Emerging Technologies, 2006
Asia Communications and Photonics Conference and Exhibition, 2009