Experimental Characterization of Elliptical Hollow-Core Photonic Bandgap Fiber at Wavelengths within the Bandgap

Kim, Gilhwan; Cho, Taiyong; Hwang, Kyujin; Lee, Kwanil; Lee, Kyung Shik; Lee, Sang Bae

doi:10.1364/ofc.2009.othk5

Cited by 2 publications

(2 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cores with rectangular [58], [59], square [60], elliptical [61] and double elliptical [62], [63] cross sections have been produced. D-shaped fibers, which have a circular core but the cladding is cut to a flat face on one side to within a few microns of the core-clad interface so that an appreciable optical field exists outside the fiber, have also been produced [64].…”

Section: Non-circular Fiber Coresmentioning

confidence: 99%

Longitudinally graded optical fibers

Evert

James

Hawkins

et al. 2013

Fiber Lasers X: Technology, Systems, and Applications

View full text Add to dashboard Cite

Described herein, for the first time to the best of our knowledge, are optical fibers possessing significant compositional gradations along their length due to longitudinal control of the core glass composition. More specifically, MCVD-derived germanosilicate fibers were fabricated that exhibited a gradient of up to about 0.55 weight percent GeO 2 per meter. These gradients are about 1900 times greater than previously reported for fibers possessing longitudinal changes in composition. The refractive index difference is shown to change by about 0.001, representing a numerical aperture change of about 10 %, over a fiber length of less than 20 m. The lowest attenuation measured from the present longitudinally-graded fiber (LGF) was 82 dB/km at a wavelength of 1550 nm, though this is shown to result from extrinsic process-induced factors and could be reduced with further optimization. The stimulated Brillouin scattering (SBS) spectrum from the LGF exhibited a 4.4 dB increase in the spectral width, and thus reduction in Brillouin gain, relative to a standard commercial single mode fiber, over a fiber length of only 17 m.Fibers with longitudinally uniform (i.e., not gradient) refractive index profiles but differing chemical compositions among various core layers were also fabricated to determine acoustic effects of the core slug method. The refractive index of the resulting preform varies by about ± 0.00013 from the average. Upon core drilling, it was found that the core slugs had been drilled off-center from the parent preform, ii resulting in semi-circular core cross sections that were unable to guide light. As a result, optical analysis could not be conducted. Chemical composition data was obtained, however, and is described herein.A third fiber produced was actively doped with ytterbium (Yb 3+ ) and fabricated similarly to the previous fibers. The preforms were doped via the solution doping method with a solution of 0.015 M Yb 3+ derived from ytterbium chloride hexahydrate and 0.30 M Al 3+ derived from aluminum chloride hexahydrate. The doped preform was engineered to have two core layers of differing chemical composition, resulting in both a gradient refractive index profile as well as a gradient acoustic profile. While exhibiting higher loss than the original LGF, the Yb 3+ -doped fiber showed slightly better SBS suppression with preliminary calculations showing at least 6 dB reduction in Brillouin gain. Lastly, reported here is a straight-forward and flexible method to fabricate silica optical fibers of circular cladding cross-section and rectilinear cores whose aspect ratio and refractive index profile changes with position along the fiber in a deterministic way. Specifically, a modification to the process developed to produce longitudinally-graded optical fibers, was employed. Herein reported are MCVDderived germanosilicate fibers with rectangular cores where the aspect ratio changes by nearly 200 % and the average refractive index changed by about 5 %. Fiber losses were measured to be about 50 dB/km. Such rec...

show abstract

Section: Non-circular Fiber Coresmentioning

confidence: 99%

Longitudinally graded optical fibers

Evert

James

Hawkins

et al. 2013

Fiber Lasers X: Technology, Systems, and Applications

View full text Add to dashboard Cite

show abstract

Section: Non-circular Fiber Coresmentioning

confidence: 99%

Longitudinally-graded optical fibers

Evert¹,

James²,

Hawkins³

et al. 2012

Opt. Express

View full text Add to dashboard Cite

Optical fibers have become ubiquitous tools for the creation, propagation, manipulation, and detection of light. However, while the intensity of light propagating through the fiber can increase or decrease along the length through amplification or attenuation, respectively, the properties of the fiber itself generally do not, thus removing an opportunity to further control the behavior of light and performance of fiber-based devices. Shown here are optical fibers that exhibit significant changes in their longitudinal optical properties, specifically a tailored longitudinal numerical aperture change of about 12% over less than 20 meters of length. This is about 1900 times greater than previously reported. The Brillouin gain coefficient was found to decrease by over 6 dB relative to a standard commercial single mode fiber. Next generation analogs are expected to exhibit more than a 10 dB reduction in SBS gain using larger, yet still reasonably manufacturable gradients over practical lengths.

show abstract

Experimental Characterization of Elliptical Hollow-Core Photonic Bandgap Fiber at Wavelengths within the Bandgap

Cited by 2 publications

References 3 publications

Longitudinally graded optical fibers

Longitudinally graded optical fibers

Longitudinally-graded optical fibers

Contact Info

Product

Resources

About