Mr. Jeff Adams Profile

Jeff Adams

Wireless Consultant

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Author

Publications (12)

Proceedings Article | 27 November 2001 Paper

Measurement by reflection analysis of optical attenuation through windows

Eric Eisenberg, Jeff Adams, Carrie Cornish

Proceedings Volume 4530, (2001) https://doi.org/10.1117/12.449809

KEYWORDS: Reflectivity, Interfaces, Signal attenuation, Glasses, Reflection, Free space optics, Buildings, Absorption, Dielectrics, Photodetectors

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Free space optical communication systems deployed in office buildings are subject to transmission loss through windows. Window attenuation varies between 0.4 and more than 15 dB. Window attenuation values are required to calculate communications link power budget and availability. But direct measurement of window attenuation in high-rise buildings is difficult since it requires access to both sides of the window. In this paper, we present a method of measuring optical attenuation from the interior side of a window. This method is based on measuring back reflections of a laser beam propagating through a semi-transparent dielectric medium, thus eliminating the need for access to the exterior of a building. In this system, a laser beam is launched at 45 degree(s) to normal incidence in order for the user to discriminate between the various reflections from the dielectric interfaces within the medium. A photodetector is then moved through the plane of incidence and the intensities of reflections from interfaces within the medium are measured. A simple formula is used to calculate total transmission of the optical system based on the relative intensities of the incident light beam and all resulting reflections. In this approach, it is assumed that the reflectivities of the first and final interfaces are identical. The index of refraction for glass from one commercial fabricator varies little; hence the reflectivity of uncoated air-glass interfaces in a particular window is the same. The intensity of the reflection from the final interface is attenuated by the entire medium twice. By comparison of the incident, first, and final reflected intensity a transmitted intensity can be determined. The same equation is used for a medium with any number of dielectric interfaces. A measurement of optical loss through a window without access to both sides of the medium is now possible. This method has been demonstrated to be accurate (+/- 1dB) through various windows with optical losses of up to 12dB.

Proceedings Article | 24 June 1999 Paper

Application of COTS high-speed 980-nm pump laser diode and driver for free-space laser communication terminal

Eric Chan, Jeff Adams, Jonathan Saint Clair, Kenneth Morrison, Martin Sosa

Proceedings Volume 3708, (1999) https://doi.org/10.1117/12.351220

KEYWORDS: Semiconductor lasers, Commercial off the shelf technology, Avalanche photodetectors, Free space optical communications, High power lasers, Diodes, Receivers, Telecommunications, Quantum wells, Transmitters

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Proceedings Article | 27 May 1998 Paper

Application of COTS high-power laser diodes and driver for a free-space laser communication terminal

Eric Chan, Jeff Adams, Jonathan Saint Clair, Kenneth Morrison, Martin Sosa

Proceedings Volume 3266, (1998) https://doi.org/10.1117/12.308713

KEYWORDS: Semiconductor lasers, Diodes, Commercial off the shelf technology, High power lasers, Transmitters, Free space optical communications, Avalanche photodetectors, Capacitance, Modulation, Laser applications

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Proceedings Article | 4 January 1995 Paper

Tunable photoconductive switch-based microwave source

R. Aaron Falk, C. David Capps, Jeff Adams

Proceedings Volume 2343, (1995) https://doi.org/10.1117/12.198660

KEYWORDS: Switches, Microwave radiation, Switching, Wave propagation, Data modeling, Circuit switching, Semiconductors, Dielectrics, Resistors, Mathematical modeling

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Proceedings Article | 4 January 1995 Paper

Direct electro-optic measurement of the internal fields of GaAs photoconductive switches

R. Aaron Falk, Jeff Adams, C. David Capps, Stuart Ferrier, Jeffrey Krinsky

Proceedings Volume 2343, (1995) https://doi.org/10.1117/12.198645

KEYWORDS: Gallium arsenide, Electro optics, Switches, Switching, Electrodes, Polarization, Semiconducting wafers, Photoresistors, Imaging systems, Wafer-level optics

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Proceedings Article | 4 January 1995 Paper

Pre-firing electric field distribution in semi-insulating GaAs bulk avalanche switches

Robert Darling, R. Aaron Falk, C. David Capps, Jeff Adams

Proceedings Volume 2343, (1995) https://doi.org/10.1117/12.198668

KEYWORDS: Gallium arsenide, Switches, Electrons, Ionization, Switching, Electrodes, Semiconductors, Absorption, Photoresistors, Instrument modeling

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Proceedings Article | 4 January 1995 Paper

Electromagnetic wave interaction with laser-induced plasmas in GaAs

Liyue Mu, William Donaldson, Jeff Adams, R. Aaron Falk

Proceedings Volume 2343, (1995) https://doi.org/10.1117/12.198649

KEYWORDS: Plasmas, Gallium arsenide, Microwave radiation, Ionization, Electromagnetic radiation, Wavefronts, Picosecond phenomena, Doppler effect, Pulsed laser operation, Laser energy

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Proceedings Article | 9 June 1993 Paper

Time-dependent model of optically activated GaAs switch

C. David Capps, R. Aaron Falk, Jeff Adams

Proceedings Volume 1873, (1993) https://doi.org/10.1117/12.146542

KEYWORDS: Switching, Switches, Gallium arsenide, Mathematical modeling, Ionization, Pulsed laser operation, Resistors, Information operations, Lithium, Instrument modeling

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Proceedings Article | 9 June 1993 Paper

Characterization of current filamentation in GaAs photoconductive switches

Jeff Adams, R. Aaron Falk, C. David Capps, Gail Bohnhoff-Hlavacek

Proceedings Volume 1873, (1993) https://doi.org/10.1117/12.146546

KEYWORDS: Luminescence, Gallium arsenide, Switches, Picosecond phenomena, Absorption, Temperature metrology, Pulsed laser operation, Microscopes, Switching, Semiconductors

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Proceedings Article | 28 May 1993 Paper

Bulk avalanche semiconductor switches (BASS) for high-resolution ultrawideband radar (UWBR) applications

Heikki Helava, Michael Herman, Charles Leung, Jeffrey Oicles, Larry Ragle, Susan Wessman, R. Aaron Falk, Jeff Adams, Stephen Davis

Proceedings Volume 1875, (1993) https://doi.org/10.1117/12.145525

KEYWORDS: Switches, Microwave radiation, Video, Radar, UWB radar, Semiconductors, Reliability, Gallium arsenide, High power microwaves, Solid state electronics

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Proceedings Article | 12 May 1992 Paper

Dark current characterization of photoconductive switches

Jeff Adams, R. Aaron Falk, C. David Capps, Stuart Ferrier

Proceedings Volume 1632, (1992) https://doi.org/10.1117/12.59063

KEYWORDS: Switches, Gallium arsenide, Switching, Resistance, Semiconductors, Electrodes, Electrons, Surface finishing, Ionization, Temperature metrology

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Proceedings Article | 1 March 1991 Paper

Temporal model of optically initiated GaAs avalanche switches

R. Aaron Falk, Jeff Adams

Proceedings Volume 1378, (1991) https://doi.org/10.1117/12.25068

KEYWORDS: Switching, Gallium arsenide, Switches, Pulsed power, Ionization, Semiconductor lasers, Data modeling, Instrument modeling, Oscilloscopes, Chlorine

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Showing 5 of 12 publications

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