Experimental Evaluation of Passive Polarization Compensation Techniques for Fiber-Distributed Polarization-Entangled Photons
- URL: http://arxiv.org/abs/2609.02554v1
- Date: Wed, 02 Sep 2026 13:05:30 GMT
- Title: Experimental Evaluation of Passive Polarization Compensation Techniques for Fiber-Distributed Polarization-Entangled Photons
- Abstract summary: Entanglement distribution through optical fibers is essential for quantum communication networks.<n> fiber transmission can alter photon polarization and modify the observed correlations of polarization-entangled states.<n>We experimentally evaluate two passive polarization compensation techniques.
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- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: Entanglement distribution through optical fibers is essential for quantum communication networks; however, fiber transmission can alter photon polarization and modify the observed correlations of polarization-entangled states, necessitating polarization compensation to recover the desired entangled state in the measurement basis. Here, we experimentally evaluate two passive polarization compensation techniques: a free-space Quarter-Half-Quarter (QHQ) waveplate configuration and an in-fiber three-paddle Fiber Polarization Controller (FPC). The polarization transformation along each downconverted-photon path is independently compensated through a systematic path-by-path optimization procedure. Using both techniques, we recover high-quality polarization correlations and entanglement, with visibilities exceeding $93\%$ in three mutually unbiased bases and fidelities above $94.5\%$. The results demonstrate comparable restoration using free-space waveplate-based and fiber-based control, establishing a systematic framework for laboratory and short-reach quantum communication links.
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