Empirical verification of principal mode orthogonality and relative phase calibration in photonic lanterns
Abstract
Photonic lanterns efficiently map input spatial modes to single-mode outputs for applications like high angular resolution imaging and nulling interferometry. However, manufacturing limits prevent full control over the device's mode transfer matrix at the design stage, making empirical characterisation essential. In this work we further analyse a dataset of direct measurements of a photonic lantern's principal modes using digital off-axis holography over a 73 nm range near 1550 nm. By analysing the electric field directly, we find that the principal modes are significantly more orthogonal than random vectors in a space of the same size, as expected for near-adiabatic devices. We propose metrics for quantifying this effect, noting that mode converters with orthogonal principal modes provide better conditioned inverse solvers. We also simulate additional measurements that characterisation systems could take, where the orthogonality would be leveraged to determine the relative phase between principal modes.
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BibTeX
@misc{taras2026empirical,
title = {{Empirical verification of principal mode orthogonality and relative phase calibration in photonic lanterns}},
author = {Adam K. Taras and Barnaby R. M. Norris and Christopher Betters and Daniel S. Dahl and Nathan Long and Andrew Ross-Adams and Peter G. Tuthill and Jin Wei and Sergio Leon-Saval},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.14767},
eprint = {2607.14767},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.14767},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Empirical verification of principal mode orthogonality and relative phase calibration in photonic lanterns
AU - Adam K. Taras
AU - Barnaby R. M. Norris
AU - Christopher Betters
AU - Daniel S. Dahl
AU - Nathan Long
AU - Andrew Ross-Adams
AU - Peter G. Tuthill
AU - Jin Wei
AU - Sergio Leon-Saval
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2607.14767
UR - https://arxiv.org/abs/2607.14767
AB - Photonic lanterns efficiently map input spatial modes to single-mode outputs for applications like high angular resolution imaging and nulling interferometry. However, manufacturing limits prevent full control over the device's mode transfer matrix at the design stage, making empirical characterisation essential. In this work we further analyse a dataset of direct measurements of a photonic lantern's principal modes using digital off-axis holography over a 73 nm range near 1550 nm. By analysing the electric field directly, we find that the principal modes are significantly more orthogonal than random vectors in a space of the same size, as expected for near-adiabatic devices. We propose metrics for quantifying this effect, noting that mode converters with orthogonal principal modes provide better conditioned inverse solvers. We also simulate additional measurements that characterisation systems could take, where the orthogonality would be leveraged to determine the relative phase between principal modes.
ER -