Photonic Bandgap Fibers
Photonic bandgap fibers are optical fibers where a photonic bandgap effect rather than a fiber core region with increased refractive index is utilized for guiding light. Such a guiding mechanism normally works only in a limited wavelength region. The conceptually simplest kind of realization is a kind of two-dimensional Bragg mirror.
The earliest realization of photonic bandgap fibers, called Bragg fibers, was based on concentric rings with different refractive index . Later, a special type of photonic crystal fiber has been developed, which also implements guidance with a photonic bandgap [3, 6], but in this case based on tiny air holes.
The refractive index of the core itself can be lower than that of the cladding structure. The core can even be hollow (→ hollow-core fibers), so that its refractive index is that of air (close to 1). As most of the light is then propagating in air rather than in glass (air-guiding fibers), such kinds of hollow-core photonic bandgap fibers may be used for guiding light in spectral regions where the absorption in the glass is relatively high. For example, light from a CO2 laser may be guided. Also, hollow-core fibers have a very weak nonlinearity, which makes them promising e.g. for the dispersive compression of ultrashort pulses with high peak power, or for the delivery of high-power laser beams.
However, photonic bandgap fibers are generally more difficult to produce due to their tight fabrication tolerances, have a limited bandwidth for low-loss transmission, and often exhibit relatively high propagation losses. It is also substantially more difficult to understand and model their propagation characteristics, compared to index-guiding fibers.
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|||P. Yeh, A. Yariv, and E. Marom, “Theory of Bragg fiber”, J. Opt. Soc. Am. 68 (9), 1196 (1978), doi:10.1364/JOSA.68.001196|
|||C. M. de Sterke et al., “Differential losses in Bragg fibers”, J. Appl. Phys. 76 (2), 680 (1993), doi:10.1063/1.357811|
|||T. A. Birks et al., “Full 2-d photonic bandgaps in silica/air structures”, Electron. Lett. 31, 1941 (1995), doi:10.1049/el:19951306|
|||J. Broeng et al., “Highly increased photonic band gaps in silica/air structures”, Opt. Commun. 156, 240 (1998), doi:10.1016/S0030-4018(98)00470-2|
|||Y. Fink et al., “A dielectric omnidirectional reflector”, Science 282, 1679 (1998), doi:10.1126/science.282.5394.1679|
|||R. F. Cregan et al., “Single-mode photonic band gap guidance of light in air”, Science 285, 1537 (1999) (first hollow-core PCF), doi:10.1126/science.285.5433.1537|
|||S. Johnson et al., “Low-loss asymptotically single-mode propagation in large-core OmniGuide fibers”, Opt. Express 9 (13), 748 (2001), doi:10.1364/OE.9.000748|
|||K. Saitoh and M. Koshiba, “Photonic bandgap fibers with high birefringence”, IEEE Photon. Technol. Lett. 14, 1291 (2002), doi:10.1109/LPT.2002.801045|
|||B. Temelkuran et al., “Wavelength-scalable hollow optical fibres with large photonic bandgaps for CO2 laser transmission”, Nature 420, 650 (2002), doi:10.1038/nature01275|
|||S. Guo et al., “Comparative analysis of Bragg fibers”, Opt. Express 12 (1), 198 (2004), doi:10.1364/OPEX.12.000198|
|||P. J. Roberts et al., “Ultimate low loss of hollow-core photonic crystal fibres”, Opt. Express 13 (1), 236 (2005), doi:10.1364/OPEX.13.000236|
|||G. Ren et al., “Low-loss all-solid photonic bandgap fiber”, Opt. Lett. 32 (9), 1023 (2007), doi:10.1364/OL.32.001023|
|||S. Février et al., “High-power photonic-bandgap fiber laser”, Opt. Lett. 33 (9), 989 (2008), doi:10.1364/OL.33.000989|
|||Z. Várallyay et al., “Photonic bandgap fibers with resonant structures for tailoring the dispersion”, Opt. Express 17 (14), 11869 (2009), doi:10.1364/OE.17.011869|
|||W. Li et al., “151 W monolithic diffraction-limited Yb-doped photonic bandgap fiber laser at ∼978 nm”, Opt. Express 27 (18), 24972 (2019), doi:10.1364/OE.27.024972|
|||B. Pulford et al., “kW-level monolithic single-mode narrow-linewidth all-solid photonic bandgap fiber amplifier”, Opt. Lett. 46 (18), 4458 (2021), doi:10.1364/OL.434879|