Optical side scattering radiometry for high resolution, wide dynamic range longitudinal assessment of optical fibers

Abstract

Current optical reflectometric techniques used to characterize optical fibers have to trade-off longitudinal range with spatial resolution and therefore struggle to provide simultaneously wide dynamic range (>20dB) and high resolution (<10cm). In this work, we develop and present a technique we refer to as Optical Side Scattering Radiometry (OSSR) capable of resolving discrete and distributed scattering properties of fibers along their length with up to 60dB dynamic range and 5cm spatial resolution. Our setup is first validated on a standard single mode telecoms fiber. Then we apply it to a record-length 11km hollow core photonic band-gap fiber (HC-PBGF) the characterization requirements of which lie far beyond the capability of standard optical reflectometric instruments. We next demonstrate use of the technique to investigate and explain the unusually high loss observed in another HC-PBGF and finally demonstrate its flexibility by measuring a HC-PBGF operating at a wavelength of 2µm. In all of these examples, good agreement between the OSSR measurements and other well-established (but more limited) characterization methods, i.e. cutback loss and OTDR, was obtained.

Power Coupling Between Light Diffusing Fibers: Modelling and Validation

“…The fiber attenuation of the employed fiber at 1550 nm, 976 nm, and 520 nm, has been evaluated by side-scattering technique [29], [30], resulting in the estimated values of 0.86 ± 0.04 m −1 , 1.46 ± 0.01 m −1 , and 1.86 ±0.03 m −1 respectively.…”

Detailed study of macrobending effects in a wide transmission bandwidth hollow-core photonic bandgap fiber

“…Outside the low loss region, the fiber shows transmission with higher loss from ~1225 to 1725nm, with two broad loss peaks due to groups of surface modes at around 1350 and 1425nm; these can be easily identified in the spectral transmission recorded in "loose" condition shown in Fig 2(a). In order to assess the longitudinal uniformity of this fiber, a novel side scattering measurement was carried out for the whole fiber length 6 . The result is shown in Fig 3 (c), in which a flat slope corresponding to ~5dB/km loss is observed and only minor deviations and very small scattering events, demonstrating that the fiber structure is highly uniform along the full length.…”

The Structural Defects and Optical Performance of Polarization-Maintaining Hollow-Core Photonic Bandgap fiber

“…According to Sagnac effect [15], the long fiber loop is beneficial for improving the precision of FOGs, which requires optical fibers to have both long distance and high performance. However, due to the structural complexity, HC-PBGF is affected by the instability factors during its long-distance fabrication process and prone to structural defects [16]. Previous study shows that the structural defects of HC-PBGF leads to the degradation of fiber longitude uniformity and fiber loss [17], [18], [19].…”