New Method for Path-length Equalization of Long Single-mode Fibers for Interferometry
Abstract
The ability to use single mode (SM) fibers for beam transport in optical interferometry offers practical advantages over conventional long vacuum pipes. One challenge facing fiber transport is maintaining constant differential path length in an environment where environmental thermal variations can lead to cm-level variations from day to night. We have fabricated three composite cables of length 470 m, each containing 4 copper wires and 3 SM fibers that operate at the astronomical H band (1500-1800 nm). Multiple fibers allow us to test performance of a circular core fiber (SMF28), a panda-style polarization-maintaining (PM) fiber, and a lastly a specialty dispersion-compensated PM fiber. We will present experimental results using precision electrical resistance measurements of the of a composite cable beam transport system. We find that the application of 1200 W over a 470 m cable causes the optical path difference in air to change by 75 mm (+/- 2 mm) and the resistance to change from 5.36 to 5.50 Ω. Additionally, we show control of the dispersion of 470 m of fiber in a single polarization using white light interference fringes (λc=1575 nm, Δλ=75 nm) using our method.
Versions
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BibTeX
@misc{anderson2026method,
title = {{New Method for Path-length Equalization of Long Single-mode Fibers for Interferometry}},
author = {M. Anderson and J. D. Monnier and K. Ozdowy and J. Woillez and G. Perrin},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.10771},
eprint = {2609.10771},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.10771},
}
RIS
TY - UNPB
TI - New Method for Path-length Equalization of Long Single-mode Fibers for Interferometry
AU - M. Anderson
AU - J. D. Monnier
AU - K. Ozdowy
AU - J. Woillez
AU - G. Perrin
PY - 2026
DA - 2026/09/09
PB - arXiv
DO - 10.48550/arxiv.2609.10771
UR - https://arxiv.org/abs/2609.10771
AB - The ability to use single mode (SM) fibers for beam transport in optical interferometry offers practical advantages over conventional long vacuum pipes. One challenge facing fiber transport is maintaining constant differential path length in an environment where environmental thermal variations can lead to cm-level variations from day to night. We have fabricated three composite cables of length 470 m, each containing 4 copper wires and 3 SM fibers that operate at the astronomical H band (1500-1800 nm). Multiple fibers allow us to test performance of a circular core fiber (SMF28), a panda-style polarization-maintaining (PM) fiber, and a lastly a specialty dispersion-compensated PM fiber. We will present experimental results using precision electrical resistance measurements of the of a composite cable beam transport system. We find that the application of 1200 W over a 470 m cable causes the optical path difference in air to change by 75 mm (+/- 2 mm) and the resistance to change from 5.36 to 5.50 Ω. Additionally, we show control of the dispersion of 470 m of fiber in a single polarization using white light interference fringes (λc=1575 nm, Δλ=75 nm) using our method.
ER -