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

Chen, Y.; Sandoghchi, Seyed Reza; Numkam, E.; Bradley, Thomas D.; Hayes, J. R.; Wheeler, Natalie V.; Jasion, Gregory T.; Gray, D. R.; Poletti, Francesco; Petrovich, M. N.; Richardson, David J.

doi:10.1117/12.2225861

Cited by 3 publications

(1 citation statement)

References 10 publications

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“…At this bend diameter, the PBGF suffers virtually no noticeable additional confinement loss. The resilience of PBGFs to bends is well known and documented, and our simulations at the smaller bend radius of 1 cm still show little additional loss near the centre of the bandgap, as also confirmed in experiments [251,252]. This comes as no surprise since the same principles that endow them with low leakage loss are at play in keeping their bend loss low.…”

Section: Macrobend Loss In Hollow-core Fiberssupporting

confidence: 84%

Loss in hollow-core optical fibers: mechanisms, scaling rules, and limits

Fokoua¹,

Mousavi²,

Jasion³

et al. 2023

Adv. Opt. Photon.

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Over the past few years, progress in hollow-core optical fiber technology has reduced the attenuation of these fibers to levels comparable to those of all-solid silica-core single-mode fibers. The sustained pace of progress in the field has sparked renewed interest in the technology and created the expectation that it will one day enable realization of the most transparent light-propagating waveguides ever produced, across all spectral regions of interest. In this work we review and analyze the various physical mechanisms that drive attenuation in hollow-core optical fibers. We consider both the somewhat legacy hollow-core photonic bandgap technology as well as the more recent antiresonant hollow-core fibers. As both fiber types exploit different guidance mechanisms from that of conventional solid-core fibers to confine light to the central core, their attenuation is also dominated by a different set of physical processes, which we analyze here in detail. First, we discuss intrinsic loss mechanisms in perfect and idealized fibers. These include leakage loss, absorption, and scattering within the gas filling the core or from the glass microstructure surrounding it, and roughness scattering from the air–glass interfaces within the fibers. The latter contribution is analyzed rigorously, clarifying inaccuracies in the literature that often led to the use of inadequate scaling rules. We then explore the extrinsic contributions to loss and discuss the effect of random microbends as well as that of other perturbations and non-uniformities that may result from imperfections in the fabrication process. These effects impact the loss of the fiber predominantly by scattering light from the fundamental mode into lossier higher-order modes and cladding modes. Although these contributions have often been neglected, their role becomes increasingly important in the context of producing, one day, hollow-core fibers with sub-0.1-dB/km loss and a pure single-mode guidance. Finally, we present general scaling rules for all the loss mechanisms mentioned previously and combine them to examine the performance of recently reported fibers. We lay some general guidelines for the design of low-loss hollow-core fibers operating at different spectral regions and conclude the paper with a brief outlook on the future of this potentially transformative technology.

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Section: Macrobend Loss In Hollow-core Fiberssupporting

confidence: 84%

Loss in hollow-core optical fibers: mechanisms, scaling rules, and limits

Fokoua¹,

Mousavi²,

Jasion³

et al. 2023

Adv. Opt. Photon.

View full text Add to dashboard Cite

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Detailed study of bending effects in large mode area segmented cladding fibers

Ma¹,

Ning²,

Li³

et al. 2016

Appl. Opt.

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This paper studies the bending effects on segmented cladding fibers (SCFs) in detail. Rod-type SCFs have offered large effective mode areas (EMAs) very successfully. The low-index segments in the design also enable the optical fibers to be bend-resistant. In this paper, the bending performance of the SCFs has been investigated by using the finite element method. The results indicate that SCFs can provide low-loss effective single-mode operation in a wide bandwidth under a bent configuration, due to the leakage losses of the higher-order modes (HOMs). A large ratio between the HOMs and the fundamental mode losses can be ensured, over a wide range of duty cycle, refractive index difference, and bending radius. Therefore, the required fabrication accuracy decreases. The mode loss ratio and EMA are independent of the bending orientation. Operating at 1550 nm and 10 cm bend radius, large EMA (754 μm²) is achievable with a large loss ratio (>30). The trade-offs between loss, EMA, and bending are studied. The structure has potential for compact high power fiber lasers, amplifiers, and beam delivery applications.

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