New age fibers: the children of the photonic revolution

Focal ratio degradation: a new perspective

“…A standard Gaussian function was fitted to the truncated FRD radial profile data [2], [11], [12] . The Gaussian was a good fit to the central peak of the 8nm rms data, however it provided a poor fit to the energy in the wings of the profile (see Figure 7).…”

“…The cleaved output gave an end-face surface roughness δ o~2 5 nm rms. A series of FRD measurements was taken using the parallel laser beam technique [11], [12] in which a collimated HeNe laser beam is injected into the fiber at various input angles θ i , the fiber output is projected onto a screen which is re-imaged onto the ST-7 CCD as shown in Figure 1. Fiber end-face surface roughness measurements were made using a WYKO NT3300 Optical Surface Profiler in Vertical ScanningInterferometry (VSI) mode and an Olympus optical microscope in phase contrast mode was used to inspect and image the fiber end-faces.…”

“…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. The parallel laser beam technique is highly sensitive to small changes in FRD and is commonly used as a quick look technique however to quantify FRD it assumes that the radial profile of the FRD distribution is a Gaussian and measures FRD in terms of the FWHM [2], [11], [12] . This method works well when measuring the modal diffusion component of FRD because Gloge's model [13] shows modal diffusion to be represented as a Gaussian profile, however if scattering is present the FRD distribution deviates away from a Gaussian profile.…”

“…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.…”

Prototype development of the integral-field unit for VIRUS

“…For details with respect to FBP transmission properties see Haynes at al. 14 . Fibers of this type and the AS200220UVPI fiber from FiberTech (www.fibertech.de) were ordered and tested for FRD properties in the laboratory at AIP (see §6).…”