The quantum statistics of parametric oscillation in a medium with cubic polarization is investiga... more The quantum statistics of parametric oscillation in a medium with cubic polarization is investigated in parametric approximation. Starting from an effective hamiltonian containing Bose operators of the signal, idler and pump mode and their coupling to heat baths, we obtain a c-number Fokker-Planck equation and the stochastically equivalent Langevin equations. These equations are solved, below threshold, well above threshold and near threshold. The linewidth of the signal and idler wave and their autocorrelation and crosscorrelation functions are calculated, characteristic differences between the four-photon and the three-photon parametric oscillators are discussed. The solution of the Fokker-Planck equation near threshold for a multimode pump laser is also obtained.
Generating supercontinuum in dispersion varying As2S3 waveguides
Fiber Optic Sensors and Applications XVI, 2019
We simulate supercontinuum generation for various shapes of a dispersion varying As2S3 waveguides... more We simulate supercontinuum generation for various shapes of a dispersion varying As2S3 waveguides on MgF2 substrate with air cladding. The supercontinuum generation is simulated for pulses of 2000 W peak power and 50 fs pulse width centered at 1.55 μm wavelength. For a uniform waveguide the generated spectrum is considerably narrower than that for a non-uniform waveguide. This is because the non-uniform waveguide allows a continuous phase matching of the generated waves through nonlinear interaction. We have demonstrated that a high coefficient of nonlinear refractive index is necessary for generating supercontinuum with large bandwidths. Larger supercontinuum bandwidth is predicted for waveguides with increasing As2S3 thickness along the propagation direction.
An edge-coupled receiver OEIC using AlInAs/InGaAs HBTs
1993 (5th) International Conference on Indium Phosphide and Related Materials
The authors report on a novel edge-coupled optical receiver optoelectronic integrated circuit (OE... more The authors report on a novel edge-coupled optical receiver optoelectronic integrated circuit (OEIC) fabricated in AlInAs/InGaAs heterostructure bipolar transistor (HBT) technology. The edge coupled geometry is compatible with the multi-fiber array connector technology. The receiver consists of a waveguide pin detector, a transimpedance preamplifier and a second voltage amplifier stage. The pin has been realized in a standard HBT layer
MBE growth of (GaAs)m/(AlAs)n short-period superlattices and their application in fabricating visible lasers
We report on the fabrication and performance characteristics of (GaAs)3/(AlAs)1 short-period supe... more We report on the fabrication and performance characteristics of (GaAs)3/(AlAs)1 short-period superlattices (SPSs) quantum well lasers emitting at 737 nm. The SPSs consists of eight periods of 3 and 1 ML of GaAs and AlAs, respectively. The (GaAs)m/(AlAs)n SPSs have many advantages over their equivalent AlGaAs alloy counterparts. The broad area threshold current density, Jth, for 500 micrometers long lasers is 510 A cm-2. The 500 micrometers -long ridge waveguide lasers have a threshold current of 48 mA with a characteristic temperature of 68 K in the temperature range 19 to 60 degree(s)C. The external differential quantum efficiency near threshold is 0.58 mW/mA/facet. The devices lase in a single mode with spectral width within the resolution limit of the spectrometer.
as soon as possible after acceptance. Copyediting, typesetting, and review of the resulting proof... more as soon as possible after acceptance. Copyediting, typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication of the Version of Record (VoR). Please note that during production and pre-press, errors may be discovered which could affect the content.
Optical and electrical characteristics of pulsating 1.3 µm InGaAsP double heterostructure lasers
1980 International Electron Devices Meeting, 1980
ABSTRACT Self sustained pulsations, superlinear emission and negative resistance behavior of seve... more ABSTRACT Self sustained pulsations, superlinear emission and negative resistance behavior of several 1.3 µm InGaAsP stripe geometry DH lasers are studied as a function of temperature and drive current. The pulsations are observed in a certain current range above threshold. This current range increases with increasing temperature. Also the maximum modulation increases with increasing temperature. The differential quantum efficiency in the region of superlinear emission was found to increase with increasing temperature and the magnitude of negative resistance decreased with increasing temperature. Time resolved measurements of the near field shows that a self-focussing of the optical beam occurs during the emission of the pulse. These phenomenon are predominently observed in nitride-stripe lasers.
All-optical OR operation has been demonstrated using a semiconductor optical amplifier (SOA) and ... more All-optical OR operation has been demonstrated using a semiconductor optical amplifier (SOA) and delayed interferometer (DI) at 80 Gb/s. The DI is based on a polarization maintaining loop mirror. Q-factor of the operation is discussed through numerical simulations. The results show the OR gate operation rate is limited by the gain recovery time and input pulse energy.
An all-optical logic AND gate is demonstrated by using a semiconductor optical amplifier (SOA) ba... more An all-optical logic AND gate is demonstrated by using a semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer (MZI). The AND results are numerically analyzed by solving the rate equation of SOA. Q-factor values have been calculated. The operation of the AND logic gate is experimentally demonstrated at 80 Gb/s. Operation at higher data rates is feasible using SOAs with shorter phase recovery time.
Analyses of conversion efficiency in high-speed clock recovery based on Mach-Zehnder modulator
Photonics North 2006, 2006
ABSTRACT In this paper, detailed analyses of the conversion efficiency in high-speed clock recove... more ABSTRACT In this paper, detailed analyses of the conversion efficiency in high-speed clock recovery based on Mach-Zehnder (MZ) modulator has been carried out. The theoretical results show the conversion efficiency changes with RF driving power and the mixing order. For high order clock recovery, the cascaded MZ modulator provides higher conversion efficiency. A study of clock recovery at 160 Gb/s using the cascaded MZ modulator has been carried out. The experimental results agree with the results of the analysis.
Molecular beam epitaxy growth of high performance AlGaAs/GaAs quantum well top emitting lasers
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1992
... Two Ga and two Al cells were used in a Riber-2300 MBE system to facili-tate the growth of the... more ... Two Ga and two Al cells were used in a Riber-2300 MBE system to facili-tate the growth of the required composition profile. ... 1. (a) Ai composition profile of the VCSEL structure, (b) Sche-matic cross-sectional view of a planar, gain-guided top emitting lasers with annual contacts. ...
Plasma-polymerized perfluoro(methylcyclohexane) coating on ethylene propylene diene elastomer surface: Effect of plasma processing condition on the deposition kinetics, morphology and surface energy of the film
Thin Solid Films, 2005
Plasma polymerization of perfluoro (methylcyclohexane) was carried out under cold plasma process ... more Plasma polymerization of perfluoro (methylcyclohexane) was carried out under cold plasma process operated at 13.56 MHz to deposit pore-free, uniform, ultra-thin film on an ethylene propylene diene terpolymer (EPDM) substrate in a view to modify the surface characteristics. The plasma fluoropolymeric films were formed at different plasma treatment times (from 20 s to 16 min), applied powers (20 to 100
Pseudo random word generation using regular and quantum dot semiconductor optical amplifiers
Military Communications Conference, Nov 1, 2008
Pseudo random bit sequence (PRBS) generation is important for a wide range of applications includ... more Pseudo random bit sequence (PRBS) generation is important for a wide range of applications including communication systems, pattern generation and encryption. All optical pseudo random bit sequence (PRBS) generation using both regular and quantum dot (QD) semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer have been studied. The speed of operation is limited by the gain and phase recovery times in the SOA. A key element in the fabrication of a PRBS generator is an all optical XOR. All optical XOR functionality has been demonstrated experimentally using regular semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer at 80 Gb/s. The performance of the XOR operation has been analyzed by solving the rate equation of the SOA for SOAs with both regular and QD active region. QD-SOAs should result in significantly higher speed operation. The paper shows that QD-SOA based devices can be used to produce PRBS generators that operate near 250 Gb/s.
The quantum statistics of parametric oscillation in a medium with cubic polarization is investiga... more The quantum statistics of parametric oscillation in a medium with cubic polarization is investigated in parametric approximation. Starting from an effective hamiltonian containing Bose operators of the signal, idler and pump mode and their coupling to heat baths, we obtain a c-number Fokker-Planck equation and the stochastically equivalent Langevin equations. These equations are solved, below threshold, well above threshold and near threshold. The linewidth of the signal and idler wave and their autocorrelation and crosscorrelation functions are calculated, characteristic differences between the four-photon and the three-photon parametric oscillators are discussed. The solution of the Fokker-Planck equation near threshold for a multimode pump laser is also obtained.
Generating supercontinuum in dispersion varying As2S3 waveguides
Fiber Optic Sensors and Applications XVI, 2019
We simulate supercontinuum generation for various shapes of a dispersion varying As2S3 waveguides... more We simulate supercontinuum generation for various shapes of a dispersion varying As2S3 waveguides on MgF2 substrate with air cladding. The supercontinuum generation is simulated for pulses of 2000 W peak power and 50 fs pulse width centered at 1.55 μm wavelength. For a uniform waveguide the generated spectrum is considerably narrower than that for a non-uniform waveguide. This is because the non-uniform waveguide allows a continuous phase matching of the generated waves through nonlinear interaction. We have demonstrated that a high coefficient of nonlinear refractive index is necessary for generating supercontinuum with large bandwidths. Larger supercontinuum bandwidth is predicted for waveguides with increasing As2S3 thickness along the propagation direction.
An edge-coupled receiver OEIC using AlInAs/InGaAs HBTs
1993 (5th) International Conference on Indium Phosphide and Related Materials
The authors report on a novel edge-coupled optical receiver optoelectronic integrated circuit (OE... more The authors report on a novel edge-coupled optical receiver optoelectronic integrated circuit (OEIC) fabricated in AlInAs/InGaAs heterostructure bipolar transistor (HBT) technology. The edge coupled geometry is compatible with the multi-fiber array connector technology. The receiver consists of a waveguide pin detector, a transimpedance preamplifier and a second voltage amplifier stage. The pin has been realized in a standard HBT layer
MBE growth of (GaAs)m/(AlAs)n short-period superlattices and their application in fabricating visible lasers
We report on the fabrication and performance characteristics of (GaAs)3/(AlAs)1 short-period supe... more We report on the fabrication and performance characteristics of (GaAs)3/(AlAs)1 short-period superlattices (SPSs) quantum well lasers emitting at 737 nm. The SPSs consists of eight periods of 3 and 1 ML of GaAs and AlAs, respectively. The (GaAs)m/(AlAs)n SPSs have many advantages over their equivalent AlGaAs alloy counterparts. The broad area threshold current density, Jth, for 500 micrometers long lasers is 510 A cm-2. The 500 micrometers -long ridge waveguide lasers have a threshold current of 48 mA with a characteristic temperature of 68 K in the temperature range 19 to 60 degree(s)C. The external differential quantum efficiency near threshold is 0.58 mW/mA/facet. The devices lase in a single mode with spectral width within the resolution limit of the spectrometer.
as soon as possible after acceptance. Copyediting, typesetting, and review of the resulting proof... more as soon as possible after acceptance. Copyediting, typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication of the Version of Record (VoR). Please note that during production and pre-press, errors may be discovered which could affect the content.
Optical and electrical characteristics of pulsating 1.3 µm InGaAsP double heterostructure lasers
1980 International Electron Devices Meeting, 1980
ABSTRACT Self sustained pulsations, superlinear emission and negative resistance behavior of seve... more ABSTRACT Self sustained pulsations, superlinear emission and negative resistance behavior of several 1.3 µm InGaAsP stripe geometry DH lasers are studied as a function of temperature and drive current. The pulsations are observed in a certain current range above threshold. This current range increases with increasing temperature. Also the maximum modulation increases with increasing temperature. The differential quantum efficiency in the region of superlinear emission was found to increase with increasing temperature and the magnitude of negative resistance decreased with increasing temperature. Time resolved measurements of the near field shows that a self-focussing of the optical beam occurs during the emission of the pulse. These phenomenon are predominently observed in nitride-stripe lasers.
All-optical OR operation has been demonstrated using a semiconductor optical amplifier (SOA) and ... more All-optical OR operation has been demonstrated using a semiconductor optical amplifier (SOA) and delayed interferometer (DI) at 80 Gb/s. The DI is based on a polarization maintaining loop mirror. Q-factor of the operation is discussed through numerical simulations. The results show the OR gate operation rate is limited by the gain recovery time and input pulse energy.
An all-optical logic AND gate is demonstrated by using a semiconductor optical amplifier (SOA) ba... more An all-optical logic AND gate is demonstrated by using a semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer (MZI). The AND results are numerically analyzed by solving the rate equation of SOA. Q-factor values have been calculated. The operation of the AND logic gate is experimentally demonstrated at 80 Gb/s. Operation at higher data rates is feasible using SOAs with shorter phase recovery time.
Analyses of conversion efficiency in high-speed clock recovery based on Mach-Zehnder modulator
Photonics North 2006, 2006
ABSTRACT In this paper, detailed analyses of the conversion efficiency in high-speed clock recove... more ABSTRACT In this paper, detailed analyses of the conversion efficiency in high-speed clock recovery based on Mach-Zehnder (MZ) modulator has been carried out. The theoretical results show the conversion efficiency changes with RF driving power and the mixing order. For high order clock recovery, the cascaded MZ modulator provides higher conversion efficiency. A study of clock recovery at 160 Gb/s using the cascaded MZ modulator has been carried out. The experimental results agree with the results of the analysis.
Molecular beam epitaxy growth of high performance AlGaAs/GaAs quantum well top emitting lasers
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1992
... Two Ga and two Al cells were used in a Riber-2300 MBE system to facili-tate the growth of the... more ... Two Ga and two Al cells were used in a Riber-2300 MBE system to facili-tate the growth of the required composition profile. ... 1. (a) Ai composition profile of the VCSEL structure, (b) Sche-matic cross-sectional view of a planar, gain-guided top emitting lasers with annual contacts. ...
Plasma-polymerized perfluoro(methylcyclohexane) coating on ethylene propylene diene elastomer surface: Effect of plasma processing condition on the deposition kinetics, morphology and surface energy of the film
Thin Solid Films, 2005
Plasma polymerization of perfluoro (methylcyclohexane) was carried out under cold plasma process ... more Plasma polymerization of perfluoro (methylcyclohexane) was carried out under cold plasma process operated at 13.56 MHz to deposit pore-free, uniform, ultra-thin film on an ethylene propylene diene terpolymer (EPDM) substrate in a view to modify the surface characteristics. The plasma fluoropolymeric films were formed at different plasma treatment times (from 20 s to 16 min), applied powers (20 to 100
Pseudo random word generation using regular and quantum dot semiconductor optical amplifiers
Military Communications Conference, Nov 1, 2008
Pseudo random bit sequence (PRBS) generation is important for a wide range of applications includ... more Pseudo random bit sequence (PRBS) generation is important for a wide range of applications including communication systems, pattern generation and encryption. All optical pseudo random bit sequence (PRBS) generation using both regular and quantum dot (QD) semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer have been studied. The speed of operation is limited by the gain and phase recovery times in the SOA. A key element in the fabrication of a PRBS generator is an all optical XOR. All optical XOR functionality has been demonstrated experimentally using regular semiconductor optical amplifier (SOA) based Mach-Zehnder interferometer at 80 Gb/s. The performance of the XOR operation has been analyzed by solving the rate equation of the SOA for SOAs with both regular and QD active region. QD-SOAs should result in significantly higher speed operation. The paper shows that QD-SOA based devices can be used to produce PRBS generators that operate near 250 Gb/s.
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