Temperature-Dependent Group Delay of Photonic-Bandgap Hollow-Core Fiber Tuned by Surface-Mode Coupling

Yazhou Wang, Zhengran Li, Fei Yu, Meng Wang, Ying Han, Lili Hu, Jonathan Knight

Research output: Contribution to journalArticlepeer-review

Abstract

Surface modes (SM) are highly spatially localized modes existing at the core-cladding interface of photonic-bandgap hollow-core fiber (PBG-HCF). When coupling with SM, the air modes (AM) in the core would suffer a higher confinement loss despite being spectrally within the cladding photonic bandgap, and would be highly dispersive around the avoided crossing (anti-crossing) wavelength. In this paper, we numerically explored how such avoided crossings can play an important role in the tuning of the temperature dependence of group delay of AM of PBG-HCF. At higher temperatures, both the thermo-optic effect and thermal expansion contribute to the redshift of avoided crossing wavelength, giving rise to a temperature dependence of the AM dispersion. Numerical simulations show that the redshift of avoided crossing can significantly tune the thermal coefficient of delay (TCD) of PBG-HCF from −400 ps/km/K to 400 ps/km/K, approximately −120 ppm/K to 120 ppm/K. In comparison with the known tuning mechanism by thermal-induced redshift of photonic bandgap [Fokoua et al., Optica 4, 659, 2017], the tuning of TCD by SM coupling presents a much broader tuning range and higher efficiency. Our finding may provide a new route to design PBG-HCF for propagation time sensitive applications.

Original languageEnglish
Pages (from-to)222-231
Number of pages10
JournalOptics Express
Volume30
Issue number1
DOIs
Publication statusPublished - 3 Jan 2022

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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