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Full-Text Articles in Physics

Crossover Photonic Switching Network With Cmos/Seed Smart Pixel Device And 2d Optical Fiber Bundle Array, Fengguang Luo, Mingcui Cao, Qiaoyan Hu, Anjun Wan, Jun Xu, Cong Deng, Deming Liu Nov 1999

Crossover Photonic Switching Network With Cmos/Seed Smart Pixel Device And 2d Optical Fiber Bundle Array, Fengguang Luo, Mingcui Cao, Qiaoyan Hu, Anjun Wan, Jun Xu, Cong Deng, Deming Liu

Electro-Optics and Photonics Faculty Publications

A 16 X 16 Crossover photonic switching network with hybrid integrated CMOS/SEED smart pixel device and 2D optical fiber bundle array I/O access device is reported in this paper. SEEd array devices ar used as light receivers and transmitters, while CMOS devices make efficient logical processing. 4 X 40 2D multilayer optical fiber bundle arrays are fabricated and are used as I/O access devices in the crossover photonic switching network. The center to center spacing between adjacent optical fibers in the same layer of the fiber array is 125micrometers , and the spacing between adjacent layers is 250micrometers . Displacing …


Optoelectronic Switching Network With 2d Optical Fiber Bundle Array I/O Access Device, Fengguang Luo, Mingcui Cao, Qiaoyan Hu, Anjun Wan, Jun Xu, Cong Deng, Yuan-Zhong Xu Sep 1999

Optoelectronic Switching Network With 2d Optical Fiber Bundle Array I/O Access Device, Fengguang Luo, Mingcui Cao, Qiaoyan Hu, Anjun Wan, Jun Xu, Cong Deng, Yuan-Zhong Xu

Electro-Optics and Photonics Faculty Publications

An optoelectronic switching network with 2-D optical fiber bundle arrays I/O access device is presented in this paper. An optoelectronic recirculating Banyan network based on CMOS/SEED smart pixel device is used in this configuration. Thirty-two X two single-mode fiber bundle array and 32 X 2 multi- mode fiber bundle array are fabricated respectively based on the features of high density, high precision and array permutation of the CMOS/SEED optoelectronic integrated devices. The measuring results show that the center to center spacing between adjacent optical fibers in the same layer of the fiber array is 125 micrometer, and the spacing between …


Differential Reflection Phase Shift Under Conditions Of Attenuated Internal Reflection, R. M.A. Azzam Jul 1999

Differential Reflection Phase Shift Under Conditions Of Attenuated Internal Reflection, R. M.A. Azzam

Electrical Engineering Faculty Publications

The angle-of-incidence dependence of the differential reflection phase shift Δ between p and s polarizations is considered a function of the real and imaginary parts of the relative complex dielectric function ε of an interface in the domain of fractional optical constants, i.e., under conditions of internal reflection. The constraint on complex ε such that oscillatory and monotonic angular responses are obtained is determined. A sensitive and stable technique, which is based on attenuated internal reflection ellipsometry between the Brewster angle and the critical angle, is proposed for measuring small induced absorption (εi∼10−5) in the medium …


Laser Beam Profile Deformation Effect During Bragg Acousto-Optic Interaction: A Non-Paraxial Approximation, Ray S. Huang, Chen-Wen Tarn, Partha P. Banerjee, Doungchin Cao Jul 1999

Laser Beam Profile Deformation Effect During Bragg Acousto-Optic Interaction: A Non-Paraxial Approximation, Ray S. Huang, Chen-Wen Tarn, Partha P. Banerjee, Doungchin Cao

Electrical and Computer Engineering Faculty Publications

It is commonly known that the spatial profiles of the diffracted light beams during Bragg acousto-optic interaction are distorted due to the Bragg angle selection mechanism. All the conventional studies on this effect use the paraxial approximation. But this approximation should be amended when the incident angle of the light is large enough that the diffracted light waves do not propagate closely along the optic axis of the acousto-optic diffraction system. By using a spatial Fourier transform approach, we rigorously study the light beam profile deformation effect of the diffracted light during the Bragg acousto-optic interaction beyond the paraxial approximation. …


Guest Editorial: Special Section On Acousto-Optic Devices And Optical Information Processing: Research And Developments, Partha P. Banerjee, Ting-Chung Poon Jul 1999

Guest Editorial: Special Section On Acousto-Optic Devices And Optical Information Processing: Research And Developments, Partha P. Banerjee, Ting-Chung Poon

Electrical and Computer Engineering Faculty Publications

This guest editorial provides an overview of the topical area and an introduction to the articles featured in the special section.


Examination Of Beam Propagation In Misaligned Holographic Gratings And Comparison With The Acousto-Optic Transfer Function Model For Profiled Beams, Monish Ranjan Chatterjee, David D. Reagan Jul 1999

Examination Of Beam Propagation In Misaligned Holographic Gratings And Comparison With The Acousto-Optic Transfer Function Model For Profiled Beams, Monish Ranjan Chatterjee, David D. Reagan

Electrical and Computer Engineering Faculty Publications

A transfer function formalism developed earlier for the propagation of profiled optical beams through acousto-optic Bragg cells is revisited and applied to a thick holographic grating. The results based on the holographic coupled wave model and the acousto-optic multiple scattering model are shown to be compatible, and equivalent parameters such as the Q and grating strength are defined for the two systems. Results for a Gaussian spatial profile are numerically computed and compared. For the holographic grating, a profiled beam may be interpreted as an angular misalignment or Bragg-angle mismatch problem. The case of Bragg-wavelength mismatch is also investigated for …


Output Control Of Vertical Microcavity Light Emitting Device, James A. Lott Apr 1999

Output Control Of Vertical Microcavity Light Emitting Device, James A. Lott

AFIT Patents

An improved intracavity sensor based output power control for microcavity light emitting devices. An improved phototransistor transducer is both configured and physically disposed so that it passively transmits the spurious optical energy output of the microcavity light emitting device while simultaneously generating a light determined electrical signal of easily used large magnitude that is nearly free of error. The base-collector region of the transistor is disposed with a quantum well absorbing layer and produces a signal responsive to a selected emission wavelength. The configuration of the optical energy communicating transducer is arranged so that it is improved in sensitivity and …


Direct Current Glow Discharges In Atmospheric Air, Robert H. Stark, Karl H. Schoenbach Jan 1999

Direct Current Glow Discharges In Atmospheric Air, Robert H. Stark, Karl H. Schoenbach

Bioelectrics Publications

Direct current glow discharges have been operated in atmospheric air by using 100 μm microhollow cathode discharges as plasma cathodes. The glow discharges were operated at currents of up to 22 mA, corresponding to current densities of 3.8 A/cm2 and at average electric fields of 1.2 kV/cm. Electron densities in the glow are in the range from 1012 to 1013  cm−3. Varying the current of the microhollow cathode discharge allows us to control the current in the atmospheric pressure glow discharge. Large volume atmospheric pressure air plasmas can be generated by operating microhollow cathode discharges …


Time-Resolved Reflection High-Energy Electron Diffraction Study Of The Ge(111)-C(2×8)-(1×1) Phase Transition, Xinglin Zeng, Bo Lin, Ibrahim El-Kholy, Hani E. Elsayed-Ali Jan 1999

Time-Resolved Reflection High-Energy Electron Diffraction Study Of The Ge(111)-C(2×8)-(1×1) Phase Transition, Xinglin Zeng, Bo Lin, Ibrahim El-Kholy, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The dynamics of the Ge(111)-c(2×8)-(1×1) phase transition is investigated by 100-ps time-resolved reflection high-energy electron diffraction. A laser pulse heats the surface while a synchronized electron pulse is used to obtain the surface diffraction pattern. Slow heating shows that the adatoms in Ge(111)-c(2×8) start to disorder at ∼510 K and are converted to a disordered adatom arrangement at 573 K. For heating with 100-ps laser pulses, the Ge(111)-c(2×8) reconstructed adatom arrangement starts to disorder at 584±16K, well above the onset temperature of ∼510 K for the disordering of Ge(111)-c(2×8) observed for slow …