The Experts below are selected from a list of 48390 Experts worldwide ranked by ideXlab platform
Phil Sullivan - One of the best experts on this subject based on the ideXlab platform.
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terahertz all optical modulation in a silicon polymer hybrid system
Nature Materials, 2006Co-Authors: Michael Hochberg, Tom Baehrjones, Guangxi Wang, Michael Shearn, Katherine Harvard, Jingdong Luo, Baoquan Chen, Zhengwei Shi, Rhys Lawson, Phil SullivanAbstract:Although gigahertz-scale free-carrier modulators have been demonstrated in silicon, Intensity modulators operating at terahertz speeds have not been reported because of silicon's weak ultrafast nonlinearity. We have demonstrated Intensity modulation of light with light in a silicon–polymer waveguide device, based on the all-optical Kerr effect—the ultrafast effect used in four-wave mixing. Direct measurements of time-Domain Intensity modulation are made at speeds of 10 GHz. We showed experimentally that the mechanism of this modulation is ultrafast through spectral measurements, and that Intensity modulation at frequencies in excess of 1 THz can be obtained. By integrating optical polymers through evanescent coupling to silicon waveguides, we greatly increase the effective nonlinearity of the waveguide, allowing operation at continuous-wave power levels compatible with telecommunication systems. These devices are a first step in the development of large-scale integrated ultrafast optical logic in silicon, and are two orders of magnitude faster than previously reported silicon devices.
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terahertz all optical modulation in a silicon polymer hybrid system
arXiv: Optics, 2006Co-Authors: Michael Hochberg, Tom Baehrjones, Guangxi Wang, Michael Shearn, Katherine Harvard, Baoquan Chen, Zhengwei Shi, Rhys Lawson, Jingdong Liu, Phil SullivanAbstract:Although Gigahertz-scale free-carrier modulators have been previously demonstrated in silicon, Intensity modulators operating at Terahertz speeds have not been reported because of silicon's weak ultrafast optical nonlinearity. We have demonstrated Intensity modulation of light with light in a silicon-polymer integrated waveguide device, based on the all-optical Kerr effect - the same ultrafast effect used in four-wave mixing. Direct measurements of time-Domain Intensity modulation are made at speeds of 10 GHz. We showed experimentally that the ultrafast mechanism of this modulation functions at the optical frequency through spectral measurements, and that Intensity modulation at frequencies in excess of 1 THz can be obtained in this device. By integrating optical polymers through evanescent coupling to high-mode-confinement silicon waveguides, we greatly increase the effective nonlinearity of the waveguide for cross-phase modulation. The combination of high mode confinement, multiple integrated optical components, and high nonlinearities produces all-optical ultrafast devices operating at continuous-wave power levels compatible with telecommunication systems. Although far from commercial radio frequency optical modulator standards in terms of extinction, these devices are a first step in development of large-scale integrated ultrafast optical logic in silicon, and are two orders of magnitude faster than previously reported silicon devices.
Ong, Yong Sheng - One of the best experts on this subject based on the ideXlab platform.
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Reconfigurable modular optical fibre resonance sensor system using field programmable gate array
'Glucksman Library University of Limerick', 2019Co-Authors: Ong, Yong ShengAbstract:peer-reviewedThe optical fibre sensor (OFS) has been studied for the last few decades and has found extensive use in many scientific and engineering fields including major application areas such as environmental, chemical, and biomedical. In spite of its popularity for use in a range of sensor applications, the OFS system is still facing hurdles for effective deployment in a range of environments. An OFS is a sensor that utilises an optical fibre as the sensing element or as a medium for light to propagate. A typical OFS system is physically large in size and is required to be used only within a fixed laboratory setting which limits its use in portable, on-site applications. To gain widespread use, a user friendly and portable optical sensor system is required and available for wide use. Such a system should be a device that is simple to use and the results easy to obtain and understand for personnel in the field. The work discussed in this thesis considers the development of a modular field programmable gate array (FPGA) based OFS system. The use of the FPGA in an OFS design is explored as the enabling technology. This leads to a portable sensor system design that can perform data processing functions in the field without the need for a personal computer (PC). For sensor data classification, the k-nearest neighbour (kNN) machine learning algorithm has been adopted for use in this system to achieve embedded and real-time system operation. This work has used a surface Plasmon resonance (SPR) sensor to demonstrate the feasibility of the system. The sensor is connected to a light source and photodetector using a plastic optical fibre (POF), allowing the detection of refractive index that has its resonance wavelength fall within the visible wavelength range. A tricolour red, green and blue (RGB) light emitting diode (LED) was used as the light source with single photodiode used as the photodetector. Time Domain Intensity modulation of individual colour light was used to interrogate three bands of interest in the SPR spectrum using the photodiode. The SPR sensor was developed for use in chemical sensing applications. To test and evaluate the system operation, concentrations of different glucose solutions were classified using the kNN algorithm in this sensor system to demonstrate its feasibility. Two approaches were used in this work to reduce both memory requirement and time complexity through pre-processing and hardware acceleration. This thesis is structured as follows. Chapter 1 will introduce the work and provide a rationale for the approach undertaken. The novel aspects of this contribution will be identified and discussed. Chapter 2 will review the OFS system considering both the SPR sensor and the portable, FPGA based system architecture. Chapter 3 will introduce the FPGA with its internal architecture that identifies the usefulness of the FPGA in embedded sensor system designs. Chapter 4 will introduce the kNN algorithm with different improvement techniques. The improvement technique is to lead towards an embedded classification implementation. The development of the sensor system will be discussed in Chapter 5. Chapter 6 will present the test results and embedded classification. Chapter 7 will conclude the thesis
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Reconfigurable modular optical fibre resonance sensor system using field programmable gate array
University of Limerick, 2019Co-Authors: Ong, Yong ShengAbstract:The optical fibre sensor (OFS) has been studied for the last few decades and has found extensive use in many scientific and engineering fields including major application areas such as environmental, chemical, and biomedical. In spite of its popularity for use in a range of sensor applications, the OFS system is still facing hurdles for effective deployment in a range of environments. An OFS is a sensor that utilises an optical fibre as the sensing element or as a medium for light to propagate. A typical OFS system is physically large in size and is required to be used only within a fixed laboratory setting which limits its use in portable, on-site applications. To gain widespread use, a user friendly and portable optical sensor system is required and available for wide use. Such a system should be a device that is simple to use and the results easy to obtain and understand for personnel in the field. The work discussed in this thesis considers the development of a modular field programmable gate array (FPGA) based OFS system. The use of the FPGA in an OFS design is explored as the enabling technology. This leads to a portable sensor system design that can perform data processing functions in the field without the need for a personal computer (PC). For sensor data classification, the k-nearest neighbour (kNN) machine learning algorithm has been adopted for use in this system to achieve embedded and real-time system operation. This work has used a surface Plasmon resonance (SPR) sensor to demonstrate the feasibility of the system. The sensor is connected to a light source and photodetector using a plastic optical fibre (POF), allowing the detection of refractive index that has its resonance wavelength fall within the visible wavelength range. A tricolour red, green and blue (RGB) light emitting diode (LED) was used as the light source with single photodiode used as the photodetector. Time Domain Intensity modulation of individual colour light was used to interrogate three bands of interest in the SPR spectrum using the photodiode. The SPR sensor was developed for use in chemical sensing applications. To test and evaluate the system operation, concentrations of different glucose solutions were classified using the kNN algorithm in this sensor system to demonstrate its feasibility. Two approaches were used in this work to reduce both memory requirement and time complexity through pre-processing and hardware acceleration. This thesis is structured as follows. Chapter 1 will introduce the work and provide a rationale for the approach undertaken. The novel aspects of this contribution will be identified and discussed. Chapter 2 will review the OFS system considering both the SPR sensor and the portable, FPGA based system architecture. Chapter 3 will introduce the FPGA with its internal architecture that identifies the usefulness of the FPGA in embedded sensor system designs. Chapter 4 will introduce the kNN algorithm with different improvement techniques. The improvement technique is to lead towards an embedded classification implementation. The development of the sensor system will be discussed in Chapter 5. Chapter 6 will present the test results and embedded classification. Chapter 7 will conclude the thesis
Jose Azana - One of the best experts on this subject based on the ideXlab platform.
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fiber based programmable picosecond optical pulse shaper
Journal of Lightwave Technology, 2010Co-Authors: Saju Thomas, Antonio Malacarne, Francesco Fresi, L Poti, Jose AzanaAbstract:We experimentally demonstrate a fiber-optic programmable optical pulse shaper based on time-Domain binary phase-only linear filtering, which is capable of switching picosecond pulse shapes at unprecedented sub-GHz rates by simply updating the binary signal driving an electro-optic phase-modulator (EO-PM). The required binary phase-filtering functions are computed using a genetic algorithm (GA). One limitation of the binary phase-filtering approach is the inherent symmetry of the output temporal shapes. To generate fully arbitrary time-Domain Intensity profiles (including asymmetric temporal waveforms) we must employ a multi-level phase-filtering function. However, the size of the solution-space and complexity of the computation multiplies to manifolds as the number of levels in the phase-filtering function increases. Here we numerically demonstrate a simple strategy, by combining the Gerchberg-Saxton algorithm (GSA) and GA, for the fast computation of multi-level phase-filtering functions. The performance of this approach is numerically proven by generating different asymmetric pulse shapes of practical interest, assuming experimentally feasible design parameters.
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linear characterization of optical pulses with durations ranging from the picosecond to the nanosecond regime using ultrafast photonic differentiation
Journal of Lightwave Technology, 2009Co-Authors: Yongwoo Park, Jose AzanaAbstract:In this paper, we extend the recently introduced linear technique for temporal phase reconstruction using optical ultrafast differentiation (PROUD) to achieve full characterization of ultrashort optical pulses with durations down to the picosecond regime using a well-characterized temporal stretcher (e.g., dispersive optical fiber). The proposed method is experimentally demonstrated by precisely characterizing the amplitude and phase temporal profiles of microwatt-power picosecond pulses ranging from 4 to 20 ps with both continuous and discrete temporal phase variations. Using this simple mechanism, the same PROUD setup can be used to characterize optical pulses with durations ranging from the picosecond to the nanosecond regime. We provide a comprehensive mathematical analysis of this general PROUD technique: we evaluate in detail the influence of the key specifications (e.g., different sources of noise) of the used components and instruments, namely, optical differentiator, linear temporal stretcher, and time-Domain Intensity test equipment, on the performance of the PROUD measurement system, particularly in terms of phase sensitivity in the optical pulse characterization.
Michael Hochberg - One of the best experts on this subject based on the ideXlab platform.
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terahertz all optical modulation in a silicon polymer hybrid system
Nature Materials, 2006Co-Authors: Michael Hochberg, Tom Baehrjones, Guangxi Wang, Michael Shearn, Katherine Harvard, Jingdong Luo, Baoquan Chen, Zhengwei Shi, Rhys Lawson, Phil SullivanAbstract:Although gigahertz-scale free-carrier modulators have been demonstrated in silicon, Intensity modulators operating at terahertz speeds have not been reported because of silicon's weak ultrafast nonlinearity. We have demonstrated Intensity modulation of light with light in a silicon–polymer waveguide device, based on the all-optical Kerr effect—the ultrafast effect used in four-wave mixing. Direct measurements of time-Domain Intensity modulation are made at speeds of 10 GHz. We showed experimentally that the mechanism of this modulation is ultrafast through spectral measurements, and that Intensity modulation at frequencies in excess of 1 THz can be obtained. By integrating optical polymers through evanescent coupling to silicon waveguides, we greatly increase the effective nonlinearity of the waveguide, allowing operation at continuous-wave power levels compatible with telecommunication systems. These devices are a first step in the development of large-scale integrated ultrafast optical logic in silicon, and are two orders of magnitude faster than previously reported silicon devices.
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terahertz all optical modulation in a silicon polymer hybrid system
arXiv: Optics, 2006Co-Authors: Michael Hochberg, Tom Baehrjones, Guangxi Wang, Michael Shearn, Katherine Harvard, Baoquan Chen, Zhengwei Shi, Rhys Lawson, Jingdong Liu, Phil SullivanAbstract:Although Gigahertz-scale free-carrier modulators have been previously demonstrated in silicon, Intensity modulators operating at Terahertz speeds have not been reported because of silicon's weak ultrafast optical nonlinearity. We have demonstrated Intensity modulation of light with light in a silicon-polymer integrated waveguide device, based on the all-optical Kerr effect - the same ultrafast effect used in four-wave mixing. Direct measurements of time-Domain Intensity modulation are made at speeds of 10 GHz. We showed experimentally that the ultrafast mechanism of this modulation functions at the optical frequency through spectral measurements, and that Intensity modulation at frequencies in excess of 1 THz can be obtained in this device. By integrating optical polymers through evanescent coupling to high-mode-confinement silicon waveguides, we greatly increase the effective nonlinearity of the waveguide for cross-phase modulation. The combination of high mode confinement, multiple integrated optical components, and high nonlinearities produces all-optical ultrafast devices operating at continuous-wave power levels compatible with telecommunication systems. Although far from commercial radio frequency optical modulator standards in terms of extinction, these devices are a first step in development of large-scale integrated ultrafast optical logic in silicon, and are two orders of magnitude faster than previously reported silicon devices.
Michael Shearn - One of the best experts on this subject based on the ideXlab platform.
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terahertz all optical modulation in a silicon polymer hybrid system
Nature Materials, 2006Co-Authors: Michael Hochberg, Tom Baehrjones, Guangxi Wang, Michael Shearn, Katherine Harvard, Jingdong Luo, Baoquan Chen, Zhengwei Shi, Rhys Lawson, Phil SullivanAbstract:Although gigahertz-scale free-carrier modulators have been demonstrated in silicon, Intensity modulators operating at terahertz speeds have not been reported because of silicon's weak ultrafast nonlinearity. We have demonstrated Intensity modulation of light with light in a silicon–polymer waveguide device, based on the all-optical Kerr effect—the ultrafast effect used in four-wave mixing. Direct measurements of time-Domain Intensity modulation are made at speeds of 10 GHz. We showed experimentally that the mechanism of this modulation is ultrafast through spectral measurements, and that Intensity modulation at frequencies in excess of 1 THz can be obtained. By integrating optical polymers through evanescent coupling to silicon waveguides, we greatly increase the effective nonlinearity of the waveguide, allowing operation at continuous-wave power levels compatible with telecommunication systems. These devices are a first step in the development of large-scale integrated ultrafast optical logic in silicon, and are two orders of magnitude faster than previously reported silicon devices.
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terahertz all optical modulation in a silicon polymer hybrid system
arXiv: Optics, 2006Co-Authors: Michael Hochberg, Tom Baehrjones, Guangxi Wang, Michael Shearn, Katherine Harvard, Baoquan Chen, Zhengwei Shi, Rhys Lawson, Jingdong Liu, Phil SullivanAbstract:Although Gigahertz-scale free-carrier modulators have been previously demonstrated in silicon, Intensity modulators operating at Terahertz speeds have not been reported because of silicon's weak ultrafast optical nonlinearity. We have demonstrated Intensity modulation of light with light in a silicon-polymer integrated waveguide device, based on the all-optical Kerr effect - the same ultrafast effect used in four-wave mixing. Direct measurements of time-Domain Intensity modulation are made at speeds of 10 GHz. We showed experimentally that the ultrafast mechanism of this modulation functions at the optical frequency through spectral measurements, and that Intensity modulation at frequencies in excess of 1 THz can be obtained in this device. By integrating optical polymers through evanescent coupling to high-mode-confinement silicon waveguides, we greatly increase the effective nonlinearity of the waveguide for cross-phase modulation. The combination of high mode confinement, multiple integrated optical components, and high nonlinearities produces all-optical ultrafast devices operating at continuous-wave power levels compatible with telecommunication systems. Although far from commercial radio frequency optical modulator standards in terms of extinction, these devices are a first step in development of large-scale integrated ultrafast optical logic in silicon, and are two orders of magnitude faster than previously reported silicon devices.