Scattering from side-illuminated clad glass fibers for determination of fiber parameters

Watkins, L. S.

doi:10.1364/josa.64.000767

Cited by 103 publications

(36 citation statements)

References 2 publications

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“…Many techniques have been developed to determine the refractive index and diameter of optical fibres [1][2][3][4][5][6][7][8][9][10] . The refracted near-field (RNF) method [3,4] has been commonly used .…”

Section: Introductionmentioning

confidence: 99%

“…The refracted near-field (RNF) method [3,4] has been commonly used . Another extensively employed method is the light scattering technique [5][6][7][8][9][10] . One of the advantages of this technique is its potential for conducting an on-line inspection .…”

Section: Introductionmentioning

confidence: 99%

“…In order to recover the refractive index and diameter of fibres from the measured scattering patterns, one has to not only measure but also calculate the scattering patterns . Theoretical approaches based on geometric ray optics [5][6][7][8] and wave optics [9,10] are developed .…”

Section: Introductionmentioning

confidence: 99%

“…Watkins [5] found by using ray optics that in a certain range of scattering angles the light directly backward-scattered from the fibre surface and that refracted at the fibre/air interface and scattered at the other surface of the fibre would interfere leading to a modulation of scattering patterns . The cladding/core interface then might be determined by this range .…”

Section: Introductionmentioning

confidence: 99%

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A Simple Method for Calculating Scattering Patterns of Light from Optical Fibres

Wang

1995

Journal of Modern Optics

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Simple Method for Calculating Scattering Patterns of Light from Optical Fibres

Wang

1995

Journal of Modern Optics

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“…Presby [1] has shown that the diameter of an unclad ® bre can be measured by observing the backscattered light. Watkins [2] has proposed a method in which the pro® le of a ® bre with uniform core was calculated from its scattering pattern. This method was modi® ed for an arbitrary pro® le by Okoshi and Hotate [3].…”

mentioning

confidence: 99%

Fibre-as-phase-object approximation in light scattering experiments

Starodumov¹,

Zenteno²,

Mendoza³

1998

Journal of Modern Optics

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Abstrac t.The use of an optical ® bre scattering pattern for measurements of its refractive-index pro® le and diameter through the ® bre-as-phase-object method is discussed. The exact solution from electromagnetic theory and the phase-object approximation are compared. A great discrepancy between the exact solution and the ® bre-as-phase-object approximation used in recently published papers is demonstrated and is critically analysed.Light di raction from an optical ® bre has been used for many years tomeasure the ® bre refractive index pro® le. Di erent methods were developed to recover ® bre parameters from the di raction pattern [1± 5]. Presby [1] has shown that the diameter of an unclad ® bre can be measured by observing the backscattered light. Watkins [2] has proposed a method in which the pro® le of a ® bre with uniform core was calculated from its scattering pattern. This method was modi® ed for an arbitrary pro® le by Okoshi and Hotate [3]. The drawback of this method is that a large number of data points was required. Later, Brinkmeyer [4] proposed to consider a® bre, which was immersed intoan index-matching oil, as aphase object. In this case the core± cladding refractive-index di erence is very small d n ! 1 and the amplitude distribution of aplane optical wave can be considered tobe constant inside the ® bre; this approach simpli® es the scattering pattern analysis. Recently, a new method has been proposed in [6] in order to determine ® bre parameters. As the author of that paper stated, a ® bre was considered as aphase object; in contrast to the paper of Brinkmeyer, refraction inside the ® bre was taken into account, a consideration thatÐ it was arguedÐ permitted one to avoid the need for an indexmatching oil. In this paper we show that the approach proposed in [6]is incorrect, and cannot be used to determine ® bre parameters. We derive the exact solution from electromagnetic theory, which is in good agreement with previously published experimental and theoretical results of other authors [1± 4], but is absolutely di erent from the theory and experimental results published in [6].We consider plane wave di raction from a dielectric cylinder that corresponds to the case of laser beam scattering from a ® bre. Although the term`di raction' is more correct we will use the term`scattering' following the terminology of previous papers [1± 4]. We assume that the electric ® eld of the incident wave is aligned with the ® bre axis in the vertical plane (® gure 1). In [6] the ® bre was considered as a phase object, which introduces just aphase shift. Such assumption means that the ® bre does not change the ampiltude distribution of alaser beam. In

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The Centering of Optical Fiber Coatings by Monitoring Forward Scattering Patterns-Theory and Practice

Eichenbaum¹

1980

Bell System Technical Journal

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The forward scattering pattern from a transversely illuminated polymer‐coated optical fiber is modeled with a ray‐tracing program. For polymers with a refractive index higher than that of silica, the scattering pattern contains caustic surfaces. If the coating is eccentric in a direction perpendicular to the incident rays, we show that the positions of the caustic surfaces (θA) vary monotonically with eccentricity at the rate of 0.85°/μm for small eccentricities for a coating with a 1.539 refractive index and 59.3‐μm thickness on a 110‐μm diameter silica fiber. Another identifiable feature of the pattern (θB) has a predicted small‐signal sensitivity of 1.1°/μm. The information obtained from the pattern can be used to insure well‐centered coatings on optical fibers. A simple interpretation of the scattering pattern provides an error signal to guide compensatory coating cup alignment. The results are reported of well‐centered runs obtained on two separate drawing lines by this means.

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Scattering from side-illuminated clad glass fibers for determination of fiber parameters

Cited by 103 publications

References 2 publications

A Simple Method for Calculating Scattering Patterns of Light from Optical Fibres

A Simple Method for Calculating Scattering Patterns of Light from Optical Fibres

Fibre-as-phase-object approximation in light scattering experiments

The Centering of Optical Fiber Coatings by Monitoring Forward Scattering Patterns-Theory and Practice

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