All-silica fiber with low or medium OH-content for broadband applications in astronomy

Ferwana, Saleh; Eckhardt, H. S.; Simon, T.; Klein, Karl-Friedrich; Haynes, Roger; Khalilov, Valery Kh.; Nelson, Gary W.

doi:10.1117/12.568231

Cited by 14 publications

(12 citation statements)

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“…The tapers were different in most other respects: separate manufacturers, different taper lengths, alternate fabrication techniques, as well as differing end face preparations. The tests were carried out using the same technique described in Ferwana et al (2004) for testing FRD. A HeNe laser was used to inject a nearly collimated beam into the various fiber taper samples at a series of different angles and the far-field profile of the fiber output was observed with a CCD camera.…”

Section: Experimental Setup and Measurementsmentioning

confidence: 99%

Application of fiber tapers in astronomy

2006

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Fiber tapers have the potential to significantly advance instrument technology into the realm of fully integrated optical systems. Our initial investigation was directed at the use of fiber tapers as f-ratio transformation devices. Using a technique developed for testing focal ratio degradation (FRD), a collimated light source was injected at different angles into various fiber taper samples and the far-field profile of the fiber output was observed. We compare the FRD present in the optical fiber tapers with conventional fibers and determine how effectively fiber tapers perform as image converters. We demonstrate that while silica fiber tapers may have slightly more intrinsic FRD than conventional fibers they still show promise as adiabatic mode transformers and are worth investigating further for their potential use in astronomical instruments.In this paper we present a brief review of the current status of fiber tapers with particular focus on the astronomical applications. We demonstrate the conservation of etendue in the taper transformation process and present the experimental results for a number of different taper profiles and manufacturers.

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Section: Experimental Setup and Measurementsmentioning

confidence: 99%

Application of fiber tapers in astronomy

2006

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“…An all-silica (polymer free) fibre is a promising candidate due to the recent establishment of industry standard fabrication expertise, material robustness and sufficient silica purity for high transmissivity as far down as the UV right through to the K-band ∼300 nm to 2.4 μm [4,5]. Air-clad fibres can offer extremely high numerical apertures (NA meas > 0.9 have been measured [13]).…”

Section: Introductionmentioning

confidence: 98%

“…The use of large area, high numerical aperture (NA) multimode optical fibres for the collection of light is critical in astronomy to applications such as multi-object spectroscopy (MOS) and integral-field spectroscopy (IFS) [4,5,[9][10][11]]. An important parameter used to determine the usefulness of an optical fibre for this purpose is the focal ratio degradation (FRD) [5,9,11], which quantifies the spread of the solid input angles of light during propagation.…”

Section: Introductionmentioning

confidence: 99%

“…An important parameter used to determine the usefulness of an optical fibre for this purpose is the focal ratio degradation (FRD) [5,9,11], which quantifies the spread of the solid input angles of light during propagation. Most spectroscopic techniques applied in astronomy rely on as small a FRD as possible so that the longitudinal input solid angle is as close, if not equal, to the output solid angle.…”

Section: Introductionmentioning

confidence: 99%

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Air-clad fibres for astronomical instrumentation: focal-ratio degradation

Åslund

Canning

2009

Exp Astron

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Focal-ratio degradation (FRD) of light launched into high-numerical aperture (NA) single-annulus all-silica undoped air-clad fibres at an NA of 0.54 is reported. The measured annular light distribution remained Gaussian after 30 m of propagation, but the angular FWHM of the output annulus doubled from 4 • after 1 m propagation to 8.5 • after 30 m, which is significantly larger than that reported of standard doped-silica fibres (NA < 0.22). No significant diffractive effects were observed. The design of air-clad fibres for broad-band, high-NA astrophotonics applications is discussed.

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“…Two FRD measurement techniques commonly used are the cone [5], [6], [7], [8], [9], [10] and the parallel laser beam [2], [11], [12] . The cone technique gives a good estimate of the total light loss that might be expected in a fiber based system, however it can be highly sensitive to alignment errors and does not provide information about the possible sources that may be contributing to any FRD.…”

Section: Introductionmentioning

confidence: 99%

Focal ratio degradation: a new perspective

Haynes

Withford

Dawes

et al. 2008

Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation

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We have developed an alternative FRD empirical model for the parallel laser beam technique which can accommodate contributions from both scattering and modal diffusion. It is consistent with scattering inducing a Lorentzian contribution and modal diffusion inducing a Gaussian contribution. The convolution of these two functions produces a Voigt function which is shown to better simulate the observed behavior of the FRD distribution and provides a greatly improved fit over the standard Gaussian fitting approach. The Voigt model can also be used to quantify the amount of energy displaced by FRD, therefore allowing astronomical instrument scientists to identify, quantify and potentially minimize the various sources of FRD, and optimise the fiber and instrument performance.

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All-silica fiber with low or medium OH-content for broadband applications in astronomy

Cited by 14 publications

References 0 publications

Application of fiber tapers in astronomy

Application of fiber tapers in astronomy

Air-clad fibres for astronomical instrumentation: focal-ratio degradation

Focal ratio degradation: a new perspective

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