Support-free thermally insensitive hollow core fiber coil
Support-free thermally insensitive hollow core fiber coil
Light traversing an optical fiber is subject to various local phase perturbations driven by temperature. This thermal phase sensitivity is undesirable in fiber interferometers and their applications which require that a fixed, stable phase be received after propagation. The use of hollow core fiber (HCF) has been shown to reduce this thermal phase sensitivity over solid core fibers and here we propose and demonstrate how coiling HCF to a prescribed geometry can further significantly reduce this sensitivity. Our proof-of-concept experiment shows reduction by a factor of ~90 with respect to the uncoiled HCF, and over three orders of magnitude with respect to uncoiled solid core optical fiber. Our strategy exploits a nuance of the elastic properties of fiber coils whereby the constrained thermal expansion of the composite material (fiber + coating) can result in a coil having compressed inner layers and expanded outer layers. Thermal expansion is the dominant effect responsible for thermal phase sensitivity in HCFs, and in this scheme the compressed inner coil layers compensate the thermal expansion of the outer layers. In this study we design the coil parameters using finite element simulations, studying the relationship between coil performance and its key parameters. The proof-of-principle coil has 160 mm diameter and incorporates a 548 m length of HCF out of which a 230 m section shows almost zero (slightly negative) thermal phase sensitivity. Though the coil shows low thermal phase sensitivity over tens of hours, the long-time constant viscoelastic properties of the coating materials used in the HCF under study are shown to limit these benefits. To make this strategy practical for systems with fast temperature dynamics, a coating having more stable mechanical properties could be used. For precision timing systems in which long thermal time constants are already the norm, this scheme represents a low-cost and provides a significant reduction to thermal sensitivity which is immediately practicable.
Coatings, Hollow core fiber, Optical fibers, Sensitivity, Strain, Stress, Temperature sensors, Thermal expansion, thermal phase sensitivity
3145-3152
Wei, Xuhao
7a3cbeb6-9088-4b63-85f1-dba9724e843a
Taranta, Austin
bc2e834f-0d85-44a1-a874-8150df1f73d9
Shi, Bo
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Ding, Meng
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Feng, Zitong
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Richardson, David J.
ebfe1ff9-d0c2-4e52-b7ae-c1b13bccdef3
Poletti, Francesco
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Slavík, Radan
2591726a-ecc0-4d1a-8e1d-4d0fd8da8f7d
15 May 2023
Wei, Xuhao
7a3cbeb6-9088-4b63-85f1-dba9724e843a
Taranta, Austin
bc2e834f-0d85-44a1-a874-8150df1f73d9
Shi, Bo
82147c8a-5263-460b-a260-a863aab0874f
Ding, Meng
4ce864fb-eb5c-47d6-8902-7b3785a162d7
Feng, Zitong
21760dcd-7979-4733-bc84-dea53c64a81c
Richardson, David J.
ebfe1ff9-d0c2-4e52-b7ae-c1b13bccdef3
Poletti, Francesco
9adcef99-5558-4644-96d7-ce24b5897491
Slavík, Radan
2591726a-ecc0-4d1a-8e1d-4d0fd8da8f7d
Wei, Xuhao, Taranta, Austin, Shi, Bo, Ding, Meng, Feng, Zitong, Richardson, David J., Poletti, Francesco and Slavík, Radan
(2023)
Support-free thermally insensitive hollow core fiber coil.
Journal of Lightwave Technology, 41 (10), .
(doi:10.1109/JLT.2023.3241255).
Abstract
Light traversing an optical fiber is subject to various local phase perturbations driven by temperature. This thermal phase sensitivity is undesirable in fiber interferometers and their applications which require that a fixed, stable phase be received after propagation. The use of hollow core fiber (HCF) has been shown to reduce this thermal phase sensitivity over solid core fibers and here we propose and demonstrate how coiling HCF to a prescribed geometry can further significantly reduce this sensitivity. Our proof-of-concept experiment shows reduction by a factor of ~90 with respect to the uncoiled HCF, and over three orders of magnitude with respect to uncoiled solid core optical fiber. Our strategy exploits a nuance of the elastic properties of fiber coils whereby the constrained thermal expansion of the composite material (fiber + coating) can result in a coil having compressed inner layers and expanded outer layers. Thermal expansion is the dominant effect responsible for thermal phase sensitivity in HCFs, and in this scheme the compressed inner coil layers compensate the thermal expansion of the outer layers. In this study we design the coil parameters using finite element simulations, studying the relationship between coil performance and its key parameters. The proof-of-principle coil has 160 mm diameter and incorporates a 548 m length of HCF out of which a 230 m section shows almost zero (slightly negative) thermal phase sensitivity. Though the coil shows low thermal phase sensitivity over tens of hours, the long-time constant viscoelastic properties of the coating materials used in the HCF under study are shown to limit these benefits. To make this strategy practical for systems with fast temperature dynamics, a coating having more stable mechanical properties could be used. For precision timing systems in which long thermal time constants are already the norm, this scheme represents a low-cost and provides a significant reduction to thermal sensitivity which is immediately practicable.
Text
Support-Free Thermally Insensitive Hollow Core Fiber Coil_FINAL VERSION
- Accepted Manuscript
More information
Accepted/In Press date: 21 January 2023
e-pub ahead of print date: 1 February 2023
Published date: 15 May 2023
Additional Information:
Funding Information:
The work of Xuhao Wei was supported by CSC scholarship. The work of Francesco Poletti was supported by EU ERC under Grant 682724. The work of Radan Slavík was supported by RAEng Fellowship. This work was supported by EPSRC Project Airguide Photonics, under Grant EP/P030181/1
Publisher Copyright:
© 1983-2012 IEEE.
Keywords:
Coatings, Hollow core fiber, Optical fibers, Sensitivity, Strain, Stress, Temperature sensors, Thermal expansion, thermal phase sensitivity
Identifiers
Local EPrints ID: 475941
URI: http://eprints.soton.ac.uk/id/eprint/475941
ISSN: 0733-8724
PURE UUID: 2f3c44d2-cae1-451a-b552-fddc84898e4a
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Date deposited: 31 Mar 2023 16:43
Last modified: 17 Mar 2024 03:57
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Author:
Bo Shi
Author:
Zitong Feng
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