End-capping hollow-core fibers with suppressed coupling into higher-order modes
End-capping hollow-core fibers with suppressed coupling into higher-order modes
We propose a hollow-core fiber (HCF) end-cap that incorporates a short segment of a single-mode fiber (SMF) that serves as a modal filter. To adapt the end-cap input and output beam to the desired size, the SMF was fusion spliced with short
segments of mode-field adapting graded index (GRIN) fibers on both sides. The end-cap is anti-reflective coated to minimize insertion loss and parasitic reflections. The presented proof-ofconcept experiments show its ability to suppress coupling into HCFs’ higher-order modes. For example, without any end-cap, the extinction ratio between the LP11 and the fundamental mode
was found to be as low as 9 dB when coupling light from a freespace beam that was misaligned by as little as 1.1◦ This was improved to 23 dB when inserting the developed end-cap. Such small angle misalignment often exists when aligning the input beam with 3-axis (x,y,z) stages only (rather than 5-axis that also include pitch and yaw). Finally, we glued the end-cap with the HCF, providing hermetic sealing to the HCF input/output. This is of interest for stable operation in applications that use free-space light launch or require HCF output into free space.
end-capping, higher-order mode, Hollow-core fiber (HCF), nested antiresonant nodeless fiber
1-9
Zhong, Ailing
4dd4add1-12d2-4e78-828b-a60d2b57ff83
Ding, Meng
4ce864fb-eb5c-47d6-8902-7b3785a162d7
Numkam Fokoua, Eric
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Zvanovec, Stanislav
037bcfba-8cc7-4f6f-8226-72d29fe7e636
Poletti, Francesco
9adcef99-5558-4644-96d7-ce24b5897491
Komanec, Matej
be991afd-3cb0-458a-a7c8-4557051e2bcf
Slavík, Radan
2591726a-ecc0-4d1a-8e1d-4d0fd8da8f7d
26 March 2024
Zhong, Ailing
4dd4add1-12d2-4e78-828b-a60d2b57ff83
Ding, Meng
4ce864fb-eb5c-47d6-8902-7b3785a162d7
Numkam Fokoua, Eric
d49bc8af-9293-473b-a08a-853e2cd3f68d
Zvanovec, Stanislav
037bcfba-8cc7-4f6f-8226-72d29fe7e636
Poletti, Francesco
9adcef99-5558-4644-96d7-ce24b5897491
Komanec, Matej
be991afd-3cb0-458a-a7c8-4557051e2bcf
Slavík, Radan
2591726a-ecc0-4d1a-8e1d-4d0fd8da8f7d
Zhong, Ailing, Ding, Meng, Numkam Fokoua, Eric, Zvanovec, Stanislav, Poletti, Francesco, Komanec, Matej and Slavík, Radan
(2024)
End-capping hollow-core fibers with suppressed coupling into higher-order modes.
IEEE Journal of Selected Topics in Quantum Electronics, 30 (6), , [4300909].
(doi:10.1109/JSTQE.2024.3381797).
Abstract
We propose a hollow-core fiber (HCF) end-cap that incorporates a short segment of a single-mode fiber (SMF) that serves as a modal filter. To adapt the end-cap input and output beam to the desired size, the SMF was fusion spliced with short
segments of mode-field adapting graded index (GRIN) fibers on both sides. The end-cap is anti-reflective coated to minimize insertion loss and parasitic reflections. The presented proof-ofconcept experiments show its ability to suppress coupling into HCFs’ higher-order modes. For example, without any end-cap, the extinction ratio between the LP11 and the fundamental mode
was found to be as low as 9 dB when coupling light from a freespace beam that was misaligned by as little as 1.1◦ This was improved to 23 dB when inserting the developed end-cap. Such small angle misalignment often exists when aligning the input beam with 3-axis (x,y,z) stages only (rather than 5-axis that also include pitch and yaw). Finally, we glued the end-cap with the HCF, providing hermetic sealing to the HCF input/output. This is of interest for stable operation in applications that use free-space light launch or require HCF output into free space.
Text
End_capping_hollow_core_fibers_with_suppression_of_higher_order_modes
- Accepted Manuscript
More information
e-pub ahead of print date: 26 March 2024
Published date: 26 March 2024
Additional Information:
Publisher Copyright:
© 1995-2012 IEEE.
Keywords:
end-capping, higher-order mode, Hollow-core fiber (HCF), nested antiresonant nodeless fiber
Identifiers
Local EPrints ID: 488998
URI: http://eprints.soton.ac.uk/id/eprint/488998
ISSN: 1077-260X
PURE UUID: 89bf979c-8e65-4107-b99c-920ff56709d0
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Date deposited: 10 Apr 2024 16:58
Last modified: 14 May 2024 01:41
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Contributors
Author:
Ailing Zhong
Author:
Eric Numkam Fokoua
Author:
Stanislav Zvanovec
Author:
Matej Komanec
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