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arXiv · 2506.11953

Few-MHz bandwidth tunable optical filter based on a fiber-ring resonator

Gabriele Maron·Anton Bölian·Xin-Xin Hu·Luke Masters·Arno Rauschenbeutel·Jürgen Volz
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Abstract

We present a fiber-ring resonator that realizes an ultra-narrowband, high-extinction, low-loss, tunable optical filter. It consists of a pair of commercial variable ratio directional couplers that allow precise adjustment of the filter bandwidth and its on-resonance transmission. This design also grants access to multiple modes of operation, such as a simultaneous band-stop and band-pass filter. Our characterization reveals a bandwidth of less than 2 MHz, together with an extinction exceeding 20 dB. The tunability of the filter properties establishes our device as a versatile platform for selective frequency filtering with sub-natural atomic linewidth resolution.

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Gabriele Maron, Anton Bölian, Xin-Xin Hu, Luke Masters, Arno Rauschenbeutel, Jürgen Volz. 2025-06-13. Few-MHz bandwidth tunable optical filter based on a fiber-ring resonator. https://arxiv.org/abs/2506.11953

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