2020 37th National Radio Science Conference (NRSC), 2020
In this paper, we report FDTD simulations and experimental results of novel silicon-based optical... more In this paper, we report FDTD simulations and experimental results of novel silicon-based optical microcavity comprising of two slotted micromirrors. While the normal range for silicon microcavities is limited by its absorption below 1.1 μm, we demonstrate a silicon cavity that is capable of operation from the visible spectrum till the telecom C-band. Deep reactive ion etching (DRIE) is used to fabricate the deeply etched microcavity mirrors. The structure is metallized with gold to enhance mirrors’ reflectivity. The slotted mirror and the cavity structure are simulated using finite difference time domain (FDTD), and the results are reported showing a quality factor of 2796 for visible TM excitation and a quality factor of 2346 for NIR TM excitation. The experimental results report the characteristics of the resonator and verify its operation in the NIR and visible ranges. The measured quality factor (Q) is 2067 around the 565 nm peak and 1922 around the 1550 nm peak. Such a microcavity would present a major step towards realizing visible laser on silicon for micro optofluidic applications.
Micro-Structured and Specialty Optical Fibres VI, 2020
Gas sensors are crucial instruments for different industries and air quality monitoring. Micro-el... more Gas sensors are crucial instruments for different industries and air quality monitoring. Micro-electro-mechanical system MEMS technology was proved as a solution for reducing the cost and size of spectrometers. Building gas cells with same technology enables the whole integration of the whole sensor. We present an HWG, as an example for integarted gas cell, which is fabricated on the silicon wafer using the MEMS technology. The HWG length is 2 cm long. The insertion loss of the HWG was measured. Carbon dioxide from exhaling and butane were measured using the HWG in conjunction with the MEMS based spectrometer. This proves the applicability of such HWG for portable gas sensors.
A semi-analytical method for calculating an effective model for skin is proposed showing an error... more A semi-analytical method for calculating an effective model for skin is proposed showing an error less than 10%. The model can be used to study applications such as glucose and alcohol detection efficiently.
In this work, we present a novel and simple optical solution for MEMS LiDARs. The idea is based o... more In this work, we present a novel and simple optical solution for MEMS LiDARs. The idea is based on increasing the collection optics throughput by removing the MEMS mirror from the path of the collected light, while inserting a multi-segment tapered structure to collect the light from a wide angle. The tapered also converts the large size optical spot captured to a small area compatible with the requirement of low detector noise dimensions. The expected improvement in the collected power is analyzed versus the tapering angle of a single tapered structure. A multi-segment optical system, or multiple tapered structure arranged in parallel, is also introduced allowing for the optimization of the acceptance angle and the power improvement ratio. Using a 3-segment mirror, the expected improvement is about 15x with an acceptance angle of ±30 degrees. The design of a single element taper section is fabricated using aluminum-coated acrylic and tested experimentally showing an improvement of about 7x in the coupled power through an angle of ±10 degrees in good agreement with the theoretical expectations.
Incoherent broadband cavity enhanced spectroscopy can significantly increase the effective path l... more Incoherent broadband cavity enhanced spectroscopy can significantly increase the effective path length of light-matter interaction to detect weak absorption lines over broad spectral range, for instance to detect gases in confined environments. Broadband cavity enhancement can be based on the decay time or the intensity drop technique. Decay time measurement is based on using tunable laser source that is expensive and suffers from long scan time. Intensity dependent measurement is usually reported based on broadband source using Fabry-Perot cavity, enabling short measurement time but suffers from the alignment tolerance of the cavity and the cavity insertion loss. In this work we overcome these challenges by using an alignment-free ring cavity made of an optical fiber loop and a directional coupler, while having a gain medium pumped below the lasing threshold to improve the finesse and reduce the insertion loss. Acetylene (C2H2) gas absorption is measured around 1535 nm wavelength using a semiconductor optical amplifier (SOA) gain medium. The system is analyzed for different ring resonator forward coupling coefficient and loses, including the 3-cm long gas cell insertion loss and fiber connector losses used in the experimental verification. The experimental results are obtained for a coupler ratio of 90/10 and a fiber length of 4 m. The broadband source is the amplified spontaneous emission of another SOA and the output is measured using a 70pm-resolution optical spectrum analyzer. The absorption depth and the effective interaction length are improved about an order of magnitude compared to the direct absorption of the gas cell. The presented technique provides an engineering method to improve the finesse and, consequently the effective length, while relaxing the technological constraints on the high reflectivity mirrors and free-space cavity alignment.
The characterization of long fiber cavities is essential for many systems to predict the system p... more The characterization of long fiber cavities is essential for many systems to predict the system practical performance. The conventional techniques for optical cavity characterization are not suitable for long fiber cavities due to the cavities’ small free spectral ranges and due to the length variations caused by the environmental effects. In this work, we present a novel technique to characterize long fiber cavities using multi-longitudinal mode fiber laser source and RF spectrum analyzer. The fiber laser source is formed in a ring configuration, where the fiber laser cavity length is chosen to be 15 km to ensure that the free spectral range is much smaller than the free spectral range of the characterized passive fiber cavities. The method has been applied experimentally to characterize ring cavities with lengths of 6.2 m and 2.4 km. The results are compared to theoretical predictions with very good agreement.
2016 33rd National Radio Science Conference (NRSC), 2016
Intensive industrial and academic research is oriented towards the design and fabrication of fibe... more Intensive industrial and academic research is oriented towards the design and fabrication of fiber ring lasers for application in different sensing systems. Using long fiber drum in the cavity has advantages concerning system parameters such as linewidth and frequency stability, which are vital parameters for ring laser sensors. However, the long drum increases the number of oscillating modes and decreases the power level per mode. Hence, the power level of the beating signal, in the RF domain, between the modes is deteriorated affecting the signal-to-noise ratio of the sensors. In this work, a fiber ring laser with a semiconductor optical amplifier (SOA) gain medium is presented with relatively high beating signal power level and small linewidth based on the insertion of a fiber ring resonator into the main ring. The effect of the inserted fiber ring resonator on the beating linewidth and signal power level is studied for different SOA pumping currents. It is found that the dispersive effect of the ring resonator harms the linewidth of the beating signal, if the SOA pumping current is much larger than the lasing threshold current. The presented system is implemented experimentally and optimized leading to about 34 dB improvement in the beating signal power level without sacrificing the linewidth.
Optical filters with relatively large FSR and narrow linewidth are simultaneously needed for diff... more Optical filters with relatively large FSR and narrow linewidth are simultaneously needed for different applications. The ratio between the FSR and the 3-dB linewidth is given by finesse of the filter, which is solely determined by the different energy loss mechanisms limited by the technology advancement. In this work, we present a novel coupled-cavity configuration embedding an optical filter and a gain medium; allowing an overall finesse enhancement and simultaneous FSR and 3-dB linewidth engineering beyond the technological limits of the filter fabrication method. The configuration consists of two resonators. An active ring resonator comprises an optical gain medium and a passive resonator. In one configuration, the optical filter is the passive resonator itself. In a second configuration, the passive resonator is another ring resonator that embeds the optical filter. The presented configurations using a semiconductor optical amplifier are applied one time to a mechanically Fabry-Perot filter in the first presented configuration; and a second time to a fiber ring filter in the second presented configuration. The mechanical filter has an original 3-dB linewidth of 1nm and an FSR that is larger than 100nm while the enhanced linewidth is about 0.3nm. The fiber ring filter length is 4 m and directional coupler ratios of 90/10corresponding to a 3-dBlinewidth of about 4MHz and an FSR of 47 MHz. The enhanced 3- dBlinewidth of the overall filter configuration is 200kHz, demonstrating finesse enhancement up to20 times the original finesse of the filter.
2016 33rd National Radio Science Conference (NRSC), 2016
In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The... more In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The proposed optical gyroscope is a Ring Laser Gyroscope (RLG), in which the laser cavity is a fiber ring of standard single mode fiber where a semiconductor optical amplifier is used as the gain medium for the ring laser. Taking advantage of the bidirectional nature of the ring laser cavity, two counter-propagating waves are supported in the ring cavity. The two waves are identical in terms of their optical resonance frequency due to the reciprocity of the loop in the static position. A frequency shift is introduced between the two counter-propagating waves when the loop is subjected to an angular rotation, known as the Sagnac effect, and the magnitude of the shift is proportional to the rotation rate. Due to the multi-longitudinal mode nature of the constructed ring laser, the rotation sensor optical system parameters are optimized in a trade-off between the sensitivity and the dynamic range. Special signal processing algorithms are developed to enhance the RLG sensitivity. The performance of the RLG is evaluated using a rate table and the Allan variance of the sensor is extracted. The demonstrated RLG has an excellent linear scale factor with a dynamic range up to 40°/sec and a sensitivity down to 0.2°/sec. The RLG noise specifications as extracted from the Allan variance are a bias instability of 3°/h and an angular random walk of 0.5°/Vh.
2009 IEEE/LEOS International Conference on Optical MEMS and Nanophotonics, 2009
Abstract A novel optical technique is proposed for the characterization of MEMS resonators. The p... more Abstract A novel optical technique is proposed for the characterization of MEMS resonators. The proposed technique is based on measuring the response of the resonator (resonance frequency and quality factor) optically, which eliminates the electrical parasitic effects. The proposed technique was applied to a comb-drive resonator and the obtained results show good agreement with the standard electrical technique with 2-5% deviation in the resonance frequency and 2-10% in the quality factor.
2009 4th International Conference on Design & Technology of Integrated Systems in Nanoscal Era, 2009
Abstract The International Technology Roadmap for Semiconductors (ITRS) projected value for the H... more Abstract The International Technology Roadmap for Semiconductors (ITRS) projected value for the High Performance (HP) MOSFET channel length is 10 nm at the year 2016. The FinFET is expected to replace the conventional bulk MOSFET beyond the 22 nm node due to the latter's scaling challenges. In this article the design optimization of a 10 nm FinFET is considered. It is shown that the ITRS requirements for the FinFET's driving current and switching speed can be satisfied simultaneously. The on-current and switching speed can ...
2010 International Conference on Microelectronics, 2010
Abstract A novel computationally efficient approach for simulation of quantum transport in nanosc... more Abstract A novel computationally efficient approach for simulation of quantum transport in nanoscale devices is proposed. The idea is based on partial coupling between the modes of the nanoscale device. The proposed approach, termed Partial-Coupled Mode Space (PCMS), is applied to the double-gate MOSFETs and device targets from the ITRS roadmap were simulated. A Comparison with the fully Coupled-Mode Space (CMS) was carried out. The PCMS reduces more than 65% of the computational burden while an accuracy of ...
2012 International Conference on Engineering and Technology (ICET), 2012
Abstract Quantum transport simulation in DoubleGate (DG) MOSFETs using the Non-Equilibrium Green&... more Abstract Quantum transport simulation in DoubleGate (DG) MOSFETs using the Non-Equilibrium Green's function Formalism (NEGF) in both coupled-mode space (CMS) and real space (RS) is reported. The transport models were implemented in the same simulator and used to simulate near-and long-term's targets of the ITRS for DG MOSFETs. The CMS presents the advantage of simulation time reduction without significant loss of accuracy, when sufficient number of modes is used. The computational burden is reduced by a ...
2007 Internatonal Conference on Microelectronics, 2007
Abstract The validity of the uncoupled mode space (UMS) approach for simulating double gate MOSFE... more Abstract The validity of the uncoupled mode space (UMS) approach for simulating double gate MOSFETs in the ballistic limit is examined. The mode space results are compared to the rigorous real space (RS) approach. The critical body thickness, at which the UMS results are no more accurate, is shown to be bias dependent. A computationally efficient method is developed to estimate the validity range of the UMS simulation results without comparing with RS results.
A wide angle microscanning architecture is presented in which the angular deflection is achieved ... more A wide angle microscanning architecture is presented in which the angular deflection is achieved by displacing the principle axis of a curved silicon micromirror of acylindrical shape, with respect to the incident beam optical axis. The micromirror curvature is designed to overcome the possible deformation of the scanned beam spot size during scanning. In the presented architecture, the optical axis of the beam lays inplane with respect to the substrate opening the door for a completely integrated and self-aligned miniaturized scanner. A micro-optical bench scanning device, based on translating a 200 μm focal length micromirror by an electrostatic comb-drive actuator, is implemented on a silicon chip. The microelectromechanical system has a resonance frequency of 329 Hz and a quality factor of 22. A single-mode optical fiber is used as the optical source and inserted into a micromachined groove fabricated and lithographically aligned with the microbench. Optical deflection angles up to 110 degrees are demonstrated.
A novel approach is proposed, termed Partial-Coupled Mode Space (PCMS), for simulation of quantum... more A novel approach is proposed, termed Partial-Coupled Mode Space (PCMS), for simulation of quantum transport in nanoscale devices. The PCMS integrates advantage of Coupled Mode Space (CMS) in accuracy and Uncoupled Mode Space (UMS) in reduction of computational burden. Partial coupling between the modes of the nanoscale device is achieved by coupling the odd-modes and even-modes separately. N-type FinFETs were simulated by the proposed approach and compared with the fully CMS accuracy and simulation time. The simulation was carried out on set of devices that satisfy the requirements of the International Technology Roadmap for Semiconductors (ITRS). The simulations show that our PCMS saves more than 65 % of the computational time with error less than 0.1 % and 0.01 % in the device charge and terminal current respectively compared to the CMS.
2016 33rd National Radio Science Conference (NRSC), 2016
In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The... more In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The proposed optical gyroscope is a Ring Laser Gyroscope (RLG), in which the laser cavity is a fiber ring of standard single mode fiber where a semiconductor optical amplifier is used as the gain medium for the ring laser. Taking advantage of the bidirectional nature of the ring laser cavity, two counter-propagating waves are supported in the ring cavity. The two waves are identical in terms of their optical resonance frequency due to the reciprocity of the loop in the static position. A frequency shift is introduced between the two counter-propagating waves when the loop is subjected to an angular rotation, known as the Sagnac effect, and the magnitude of the shift is proportional to the rotation rate. Due to the multi-longitudinal mode nature of the constructed ring laser, the rotation sensor optical system parameters are optimized in a trade-off between the sensitivity and the dynamic range. Special signal processing algorithms are developed to enhance the RLG sensitivity. The performance of the RLG is evaluated using a rate table and the Allan variance of the sensor is extracted. The demonstrated RLG has an excellent linear scale factor with a dynamic range up to 40°/sec and a sensitivity down to 0.2°/sec. The RLG noise specifications as extracted from the Allan variance are a bias instability of 3°/h and an angular random walk of 0.5°/Vh.
Miniaturized optical benches process free-space light propagating in-plane with respect to the su... more Miniaturized optical benches process free-space light propagating in-plane with respect to the substrate and have a large variety of applications, including the coupling of light through an optical fiber. High coupling efficiency is usually obtained using assembled micro-optical parts, which considerably increase the system cost and integration effort. In this work, we report a high coupling efficiency, monolithically integrated silicon micromirror with controlled three-dimensional (3D) curvature that is capable of manipulating optical beams propagating in the plane of the silicon substrate. Based on our theoretical modeling, a spherical micromirror with a microscale radius of curvature as small as twice the Gaussian beam Rayleigh range provides a 100% coupling efficiency over a relatively long optical path range. Introducing dimensionless parameters facilitates the elucidation of the role of key design parameters, including the mirror's radii of curvature, independent of the wavelength. A micromachining method is presented for fabricating the 3D micromirror using fluorinated gas plasmas. The measured coupling efficiency was greater than 50% over a 200-mm optical path, compared to less than 10% afforded by a conventional flat micromirror, which was in good agreement with the model. Using the 3D micromirror, an optical cavity was formed with a round-trip diffraction loss of less than 0.4%, resulting in one order of magnitude enhancement in the measured quality factor. A nearly 100% coupling was also estimated when matching the sagittal and tangential radii of curvature of the presented micromirror's surface. The reported class of 3D micromirrors may be an advantageous replacement for the optical lenses usually assembled in silicon photonics and optical benches by transforming them into real 3D monolithic systems while achieving wideband high coupling efficiency over submillimeter distances.
Diffuse reflectance infrared spectroscopy has gained traction in many industrial applications in ... more Diffuse reflectance infrared spectroscopy has gained traction in many industrial applications in the recent years due to the emergence of new generation of low cost handheld spectrometers that did not exist a decade ago. Real-time monitoring puts a limit on the sample preparation process especially with inhomogeneous samples in the food industry, like grains, hay, wheat and corn. The heterogeneity of the samples and the pseudo-random spatial arrangement of the grains in front of the optical interface, leads to prediction errors. The spatial variations depend also on the spot size of the diffuse-reflected scattered light from the sample that is collected by the spectrometer. A larger spot size leads to simultaneous averaging of a larger amount of spectrospatial information from different locations on the sample, leading to better repeatability and better prediction accuracy. Up to date, the Microelectromechanical (MEMS) based spectrometers reported in the literature have limited opti...
2020 37th National Radio Science Conference (NRSC), 2020
In this paper, we report FDTD simulations and experimental results of novel silicon-based optical... more In this paper, we report FDTD simulations and experimental results of novel silicon-based optical microcavity comprising of two slotted micromirrors. While the normal range for silicon microcavities is limited by its absorption below 1.1 μm, we demonstrate a silicon cavity that is capable of operation from the visible spectrum till the telecom C-band. Deep reactive ion etching (DRIE) is used to fabricate the deeply etched microcavity mirrors. The structure is metallized with gold to enhance mirrors’ reflectivity. The slotted mirror and the cavity structure are simulated using finite difference time domain (FDTD), and the results are reported showing a quality factor of 2796 for visible TM excitation and a quality factor of 2346 for NIR TM excitation. The experimental results report the characteristics of the resonator and verify its operation in the NIR and visible ranges. The measured quality factor (Q) is 2067 around the 565 nm peak and 1922 around the 1550 nm peak. Such a microcavity would present a major step towards realizing visible laser on silicon for micro optofluidic applications.
Micro-Structured and Specialty Optical Fibres VI, 2020
Gas sensors are crucial instruments for different industries and air quality monitoring. Micro-el... more Gas sensors are crucial instruments for different industries and air quality monitoring. Micro-electro-mechanical system MEMS technology was proved as a solution for reducing the cost and size of spectrometers. Building gas cells with same technology enables the whole integration of the whole sensor. We present an HWG, as an example for integarted gas cell, which is fabricated on the silicon wafer using the MEMS technology. The HWG length is 2 cm long. The insertion loss of the HWG was measured. Carbon dioxide from exhaling and butane were measured using the HWG in conjunction with the MEMS based spectrometer. This proves the applicability of such HWG for portable gas sensors.
A semi-analytical method for calculating an effective model for skin is proposed showing an error... more A semi-analytical method for calculating an effective model for skin is proposed showing an error less than 10%. The model can be used to study applications such as glucose and alcohol detection efficiently.
In this work, we present a novel and simple optical solution for MEMS LiDARs. The idea is based o... more In this work, we present a novel and simple optical solution for MEMS LiDARs. The idea is based on increasing the collection optics throughput by removing the MEMS mirror from the path of the collected light, while inserting a multi-segment tapered structure to collect the light from a wide angle. The tapered also converts the large size optical spot captured to a small area compatible with the requirement of low detector noise dimensions. The expected improvement in the collected power is analyzed versus the tapering angle of a single tapered structure. A multi-segment optical system, or multiple tapered structure arranged in parallel, is also introduced allowing for the optimization of the acceptance angle and the power improvement ratio. Using a 3-segment mirror, the expected improvement is about 15x with an acceptance angle of ±30 degrees. The design of a single element taper section is fabricated using aluminum-coated acrylic and tested experimentally showing an improvement of about 7x in the coupled power through an angle of ±10 degrees in good agreement with the theoretical expectations.
Incoherent broadband cavity enhanced spectroscopy can significantly increase the effective path l... more Incoherent broadband cavity enhanced spectroscopy can significantly increase the effective path length of light-matter interaction to detect weak absorption lines over broad spectral range, for instance to detect gases in confined environments. Broadband cavity enhancement can be based on the decay time or the intensity drop technique. Decay time measurement is based on using tunable laser source that is expensive and suffers from long scan time. Intensity dependent measurement is usually reported based on broadband source using Fabry-Perot cavity, enabling short measurement time but suffers from the alignment tolerance of the cavity and the cavity insertion loss. In this work we overcome these challenges by using an alignment-free ring cavity made of an optical fiber loop and a directional coupler, while having a gain medium pumped below the lasing threshold to improve the finesse and reduce the insertion loss. Acetylene (C2H2) gas absorption is measured around 1535 nm wavelength using a semiconductor optical amplifier (SOA) gain medium. The system is analyzed for different ring resonator forward coupling coefficient and loses, including the 3-cm long gas cell insertion loss and fiber connector losses used in the experimental verification. The experimental results are obtained for a coupler ratio of 90/10 and a fiber length of 4 m. The broadband source is the amplified spontaneous emission of another SOA and the output is measured using a 70pm-resolution optical spectrum analyzer. The absorption depth and the effective interaction length are improved about an order of magnitude compared to the direct absorption of the gas cell. The presented technique provides an engineering method to improve the finesse and, consequently the effective length, while relaxing the technological constraints on the high reflectivity mirrors and free-space cavity alignment.
The characterization of long fiber cavities is essential for many systems to predict the system p... more The characterization of long fiber cavities is essential for many systems to predict the system practical performance. The conventional techniques for optical cavity characterization are not suitable for long fiber cavities due to the cavities’ small free spectral ranges and due to the length variations caused by the environmental effects. In this work, we present a novel technique to characterize long fiber cavities using multi-longitudinal mode fiber laser source and RF spectrum analyzer. The fiber laser source is formed in a ring configuration, where the fiber laser cavity length is chosen to be 15 km to ensure that the free spectral range is much smaller than the free spectral range of the characterized passive fiber cavities. The method has been applied experimentally to characterize ring cavities with lengths of 6.2 m and 2.4 km. The results are compared to theoretical predictions with very good agreement.
2016 33rd National Radio Science Conference (NRSC), 2016
Intensive industrial and academic research is oriented towards the design and fabrication of fibe... more Intensive industrial and academic research is oriented towards the design and fabrication of fiber ring lasers for application in different sensing systems. Using long fiber drum in the cavity has advantages concerning system parameters such as linewidth and frequency stability, which are vital parameters for ring laser sensors. However, the long drum increases the number of oscillating modes and decreases the power level per mode. Hence, the power level of the beating signal, in the RF domain, between the modes is deteriorated affecting the signal-to-noise ratio of the sensors. In this work, a fiber ring laser with a semiconductor optical amplifier (SOA) gain medium is presented with relatively high beating signal power level and small linewidth based on the insertion of a fiber ring resonator into the main ring. The effect of the inserted fiber ring resonator on the beating linewidth and signal power level is studied for different SOA pumping currents. It is found that the dispersive effect of the ring resonator harms the linewidth of the beating signal, if the SOA pumping current is much larger than the lasing threshold current. The presented system is implemented experimentally and optimized leading to about 34 dB improvement in the beating signal power level without sacrificing the linewidth.
Optical filters with relatively large FSR and narrow linewidth are simultaneously needed for diff... more Optical filters with relatively large FSR and narrow linewidth are simultaneously needed for different applications. The ratio between the FSR and the 3-dB linewidth is given by finesse of the filter, which is solely determined by the different energy loss mechanisms limited by the technology advancement. In this work, we present a novel coupled-cavity configuration embedding an optical filter and a gain medium; allowing an overall finesse enhancement and simultaneous FSR and 3-dB linewidth engineering beyond the technological limits of the filter fabrication method. The configuration consists of two resonators. An active ring resonator comprises an optical gain medium and a passive resonator. In one configuration, the optical filter is the passive resonator itself. In a second configuration, the passive resonator is another ring resonator that embeds the optical filter. The presented configurations using a semiconductor optical amplifier are applied one time to a mechanically Fabry-Perot filter in the first presented configuration; and a second time to a fiber ring filter in the second presented configuration. The mechanical filter has an original 3-dB linewidth of 1nm and an FSR that is larger than 100nm while the enhanced linewidth is about 0.3nm. The fiber ring filter length is 4 m and directional coupler ratios of 90/10corresponding to a 3-dBlinewidth of about 4MHz and an FSR of 47 MHz. The enhanced 3- dBlinewidth of the overall filter configuration is 200kHz, demonstrating finesse enhancement up to20 times the original finesse of the filter.
2016 33rd National Radio Science Conference (NRSC), 2016
In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The... more In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The proposed optical gyroscope is a Ring Laser Gyroscope (RLG), in which the laser cavity is a fiber ring of standard single mode fiber where a semiconductor optical amplifier is used as the gain medium for the ring laser. Taking advantage of the bidirectional nature of the ring laser cavity, two counter-propagating waves are supported in the ring cavity. The two waves are identical in terms of their optical resonance frequency due to the reciprocity of the loop in the static position. A frequency shift is introduced between the two counter-propagating waves when the loop is subjected to an angular rotation, known as the Sagnac effect, and the magnitude of the shift is proportional to the rotation rate. Due to the multi-longitudinal mode nature of the constructed ring laser, the rotation sensor optical system parameters are optimized in a trade-off between the sensitivity and the dynamic range. Special signal processing algorithms are developed to enhance the RLG sensitivity. The performance of the RLG is evaluated using a rate table and the Allan variance of the sensor is extracted. The demonstrated RLG has an excellent linear scale factor with a dynamic range up to 40°/sec and a sensitivity down to 0.2°/sec. The RLG noise specifications as extracted from the Allan variance are a bias instability of 3°/h and an angular random walk of 0.5°/Vh.
2009 IEEE/LEOS International Conference on Optical MEMS and Nanophotonics, 2009
Abstract A novel optical technique is proposed for the characterization of MEMS resonators. The p... more Abstract A novel optical technique is proposed for the characterization of MEMS resonators. The proposed technique is based on measuring the response of the resonator (resonance frequency and quality factor) optically, which eliminates the electrical parasitic effects. The proposed technique was applied to a comb-drive resonator and the obtained results show good agreement with the standard electrical technique with 2-5% deviation in the resonance frequency and 2-10% in the quality factor.
2009 4th International Conference on Design & Technology of Integrated Systems in Nanoscal Era, 2009
Abstract The International Technology Roadmap for Semiconductors (ITRS) projected value for the H... more Abstract The International Technology Roadmap for Semiconductors (ITRS) projected value for the High Performance (HP) MOSFET channel length is 10 nm at the year 2016. The FinFET is expected to replace the conventional bulk MOSFET beyond the 22 nm node due to the latter's scaling challenges. In this article the design optimization of a 10 nm FinFET is considered. It is shown that the ITRS requirements for the FinFET's driving current and switching speed can be satisfied simultaneously. The on-current and switching speed can ...
2010 International Conference on Microelectronics, 2010
Abstract A novel computationally efficient approach for simulation of quantum transport in nanosc... more Abstract A novel computationally efficient approach for simulation of quantum transport in nanoscale devices is proposed. The idea is based on partial coupling between the modes of the nanoscale device. The proposed approach, termed Partial-Coupled Mode Space (PCMS), is applied to the double-gate MOSFETs and device targets from the ITRS roadmap were simulated. A Comparison with the fully Coupled-Mode Space (CMS) was carried out. The PCMS reduces more than 65% of the computational burden while an accuracy of ...
2012 International Conference on Engineering and Technology (ICET), 2012
Abstract Quantum transport simulation in DoubleGate (DG) MOSFETs using the Non-Equilibrium Green&... more Abstract Quantum transport simulation in DoubleGate (DG) MOSFETs using the Non-Equilibrium Green's function Formalism (NEGF) in both coupled-mode space (CMS) and real space (RS) is reported. The transport models were implemented in the same simulator and used to simulate near-and long-term's targets of the ITRS for DG MOSFETs. The CMS presents the advantage of simulation time reduction without significant loss of accuracy, when sufficient number of modes is used. The computational burden is reduced by a ...
2007 Internatonal Conference on Microelectronics, 2007
Abstract The validity of the uncoupled mode space (UMS) approach for simulating double gate MOSFE... more Abstract The validity of the uncoupled mode space (UMS) approach for simulating double gate MOSFETs in the ballistic limit is examined. The mode space results are compared to the rigorous real space (RS) approach. The critical body thickness, at which the UMS results are no more accurate, is shown to be bias dependent. A computationally efficient method is developed to estimate the validity range of the UMS simulation results without comparing with RS results.
A wide angle microscanning architecture is presented in which the angular deflection is achieved ... more A wide angle microscanning architecture is presented in which the angular deflection is achieved by displacing the principle axis of a curved silicon micromirror of acylindrical shape, with respect to the incident beam optical axis. The micromirror curvature is designed to overcome the possible deformation of the scanned beam spot size during scanning. In the presented architecture, the optical axis of the beam lays inplane with respect to the substrate opening the door for a completely integrated and self-aligned miniaturized scanner. A micro-optical bench scanning device, based on translating a 200 μm focal length micromirror by an electrostatic comb-drive actuator, is implemented on a silicon chip. The microelectromechanical system has a resonance frequency of 329 Hz and a quality factor of 22. A single-mode optical fiber is used as the optical source and inserted into a micromachined groove fabricated and lithographically aligned with the microbench. Optical deflection angles up to 110 degrees are demonstrated.
A novel approach is proposed, termed Partial-Coupled Mode Space (PCMS), for simulation of quantum... more A novel approach is proposed, termed Partial-Coupled Mode Space (PCMS), for simulation of quantum transport in nanoscale devices. The PCMS integrates advantage of Coupled Mode Space (CMS) in accuracy and Uncoupled Mode Space (UMS) in reduction of computational burden. Partial coupling between the modes of the nanoscale device is achieved by coupling the odd-modes and even-modes separately. N-type FinFETs were simulated by the proposed approach and compared with the fully CMS accuracy and simulation time. The simulation was carried out on set of devices that satisfy the requirements of the International Technology Roadmap for Semiconductors (ITRS). The simulations show that our PCMS saves more than 65 % of the computational time with error less than 0.1 % and 0.01 % in the device charge and terminal current respectively compared to the CMS.
2016 33rd National Radio Science Conference (NRSC), 2016
In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The... more In this work, we present an optical gyroscope based on hybrid semiconductor-fiber ring laser. The proposed optical gyroscope is a Ring Laser Gyroscope (RLG), in which the laser cavity is a fiber ring of standard single mode fiber where a semiconductor optical amplifier is used as the gain medium for the ring laser. Taking advantage of the bidirectional nature of the ring laser cavity, two counter-propagating waves are supported in the ring cavity. The two waves are identical in terms of their optical resonance frequency due to the reciprocity of the loop in the static position. A frequency shift is introduced between the two counter-propagating waves when the loop is subjected to an angular rotation, known as the Sagnac effect, and the magnitude of the shift is proportional to the rotation rate. Due to the multi-longitudinal mode nature of the constructed ring laser, the rotation sensor optical system parameters are optimized in a trade-off between the sensitivity and the dynamic range. Special signal processing algorithms are developed to enhance the RLG sensitivity. The performance of the RLG is evaluated using a rate table and the Allan variance of the sensor is extracted. The demonstrated RLG has an excellent linear scale factor with a dynamic range up to 40°/sec and a sensitivity down to 0.2°/sec. The RLG noise specifications as extracted from the Allan variance are a bias instability of 3°/h and an angular random walk of 0.5°/Vh.
Miniaturized optical benches process free-space light propagating in-plane with respect to the su... more Miniaturized optical benches process free-space light propagating in-plane with respect to the substrate and have a large variety of applications, including the coupling of light through an optical fiber. High coupling efficiency is usually obtained using assembled micro-optical parts, which considerably increase the system cost and integration effort. In this work, we report a high coupling efficiency, monolithically integrated silicon micromirror with controlled three-dimensional (3D) curvature that is capable of manipulating optical beams propagating in the plane of the silicon substrate. Based on our theoretical modeling, a spherical micromirror with a microscale radius of curvature as small as twice the Gaussian beam Rayleigh range provides a 100% coupling efficiency over a relatively long optical path range. Introducing dimensionless parameters facilitates the elucidation of the role of key design parameters, including the mirror's radii of curvature, independent of the wavelength. A micromachining method is presented for fabricating the 3D micromirror using fluorinated gas plasmas. The measured coupling efficiency was greater than 50% over a 200-mm optical path, compared to less than 10% afforded by a conventional flat micromirror, which was in good agreement with the model. Using the 3D micromirror, an optical cavity was formed with a round-trip diffraction loss of less than 0.4%, resulting in one order of magnitude enhancement in the measured quality factor. A nearly 100% coupling was also estimated when matching the sagittal and tangential radii of curvature of the presented micromirror's surface. The reported class of 3D micromirrors may be an advantageous replacement for the optical lenses usually assembled in silicon photonics and optical benches by transforming them into real 3D monolithic systems while achieving wideband high coupling efficiency over submillimeter distances.
Diffuse reflectance infrared spectroscopy has gained traction in many industrial applications in ... more Diffuse reflectance infrared spectroscopy has gained traction in many industrial applications in the recent years due to the emergence of new generation of low cost handheld spectrometers that did not exist a decade ago. Real-time monitoring puts a limit on the sample preparation process especially with inhomogeneous samples in the food industry, like grains, hay, wheat and corn. The heterogeneity of the samples and the pseudo-random spatial arrangement of the grains in front of the optical interface, leads to prediction errors. The spatial variations depend also on the spot size of the diffuse-reflected scattered light from the sample that is collected by the spectrometer. A larger spot size leads to simultaneous averaging of a larger amount of spectrospatial information from different locations on the sample, leading to better repeatability and better prediction accuracy. Up to date, the Microelectromechanical (MEMS) based spectrometers reported in the literature have limited opti...
Uploads
Papers by Yasser Sabry