Advances in optical fiber-based Faraday Rotation Diagnostics

White, A. D.; McHale, Glen; Goerz, D.A.

doi:10.1109/ppc.2009.5386240

Cited by 11 publications

(14 citation statements)

References 4 publications

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“…The Faraday Effect causes linearly polarized light in the sensing fiber to rotate when exposed to an external magnetic field in the direction of light propagation [4][5][6][7][8]. The effect in an optical fiber is illustrated in Fig.…”

Section: Basic Sensor Operationmentioning

confidence: 99%

A fiber-optic current sensor for lightning measurement applications

2015

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An optical-fiber sensor based on Faraday Effect is developed for measuring total lightning electric current. It has many unique capabilities not possible with traditional current sensors. Designed for aircraft installation, the sensor is lightweight, non-conducting, structure-conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements.Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. The broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with about 60 dB dynamic range.Three sensor systems were built with different sensitivities from different laser wavelengths. Operating at 850nm, the first system uses twisted single-mode fiber and has a 150 A -150 KA range. The second system operates at 1550nm, uses spun polarization maintaining fiber, and can measure 400 A -400 KA. Both systems were validated with rocket-triggered lightning measurements and achieved excellent results when compared to a resistive shunt. The third system operates at 1310nm, uses spun polarization maintaining fiber, and can measure approximately 300 A -300 KA. High current measurements up to 200 KA were demonstrated at a commercial lightning test facility. The system was recently installed on an aircraft and flown near icing weather conditions.

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Section: Basic Sensor Operationmentioning

confidence: 99%

A fiber-optic current sensor for lightning measurement applications

2015

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“…Optical-fiber based Faraday Rotation diagnostics are our primary means of measuring FCG current [6,7]. By looping our sensing fibers around the current carrying conductors in our generators an integer number of times, Ampere's law can be exploited to relate the observed optical rotation to generator current without any in situ calibration or geometric corrections.…”

Section: Specialized Diagnostic Capabilitymentioning

confidence: 99%

Explosive pulsed power experimental capability at LLNL

White

Milhous

Goerz

et al. 2012

2012 14th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS)

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Abstract-LLNL has developed a family of advanced magnetic flux compression generators (FCGs) used to perform high energy density physics experiments and material science studies. In recent years we have performed these experiments at explosive test sites in New Mexico and Nevada. In 2011, we re-established an explosive pulsed power test facility closer to Livermore. LLNL's Site 300 is a U.S. DOE-NNSA experimental test site situated on 7000 acres in rural foothills approximately 15 miles southeast of Livermore. It was established in 1955 as a non-nuclear explosives test facility to support LLNL's national security mission. On this site there are numerous facilities for fabricating, storing, assembling, and testing explosive devices. Site 300 is also home to some of DOE's premier facilities for hydrodynamic testing, with sophisticated diagnostics such as high-speed imaging, flash X-ray radiography, and other advanced diagnostics for performing unique experiments such as shock physics experiments, which examine how materials behave under high pressure and temperature. We have converted and upgraded one particular firing bunker at Site 300 (known as Bunker 851) to provide the necessary infrastructure to support high explosive pulsed power (HEPP) experiments. In doing so, we were able to incorporate our established practices for handling grounding, shielding, and isolation of auxiliary systems and diagnostics, in order to effectively manage the large voltages produced by FCGs, and minimize unwanted coupling to diagnostic data. This paper will discuss some of the key attributes of the Bunker 851 facility, including the specialized firesets and isolated initiation systems for multistage explosive systems, a detonator-switched seed bank that operates while isolated from earth and building ground, a fiber-optic based timing, triggering and control system, an EMI Faraday cage that completely encloses diagnostic sensors, cabling and high-resolution digitizers, optical fiber-based velocimetry and current sensor systems, and a flash X-ray radiography system. The photos and experimental results from recent FCG experiments will also be shown and discussed.

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“…2,3 The Faraday effect has found a tremendous amount of applications: spin detection in spintronics, 4-7 measurement of ellipticity and rotation angle to ascertain the Hall mobility and effective mass of free carriers, [8][9][10][11][12] investigation of thin magnetic films and magnetic multi-layers, 13,14 and pulsed current measurements. 15 The authors have been actively pursuing photonic applications of magneto-optic materials, specifically transparent switches for all-optical networks that will enable interoperability between a multitude of bit-rates, protocols, and formats, as well as allowing the operators to better scale their networks to meet the subscriber requirements and enhance their services. 16,17 In order to analyze a structure consisting of fibers, films, birefringent, and magnetic materials, it is helpful to have an analysis structure.…”

Section: Improved Formulation For Faraday Rotation Characterizationmentioning

confidence: 99%

“…With the source on the input port and terminations on the output port, we obtain the relationships in (15). Conversely with the source on the output port and terminations on the input port, we obtain the relationships in (16).…”

Section: Improved Formulation For Faraday Rotation Characterizationmentioning

confidence: 99%

Improved formulation for Faraday rotation characterization

Tioh

Weber

Mina

2011

Journal of Applied Physics

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The analysis of complex structures consisting of fibers, films, birefringent, and magnetic materials is greatly aided by the availability of an analysis structure. Jones calculus is typically utilized in the course of such analyses. However, standard Jones calculus does not account for the effect of reflections. An improved formulation for the characterization of Faraday rotation that alleviates this shortcoming is reported here and is integral for the proper analysis of devices employing magneto-optic effects.

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Advances in optical fiber-based Faraday Rotation Diagnostics

Cited by 11 publications

References 4 publications

A fiber-optic current sensor for lightning measurement applications

A fiber-optic current sensor for lightning measurement applications

Explosive pulsed power experimental capability at LLNL

Improved formulation for Faraday rotation characterization

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