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arXiv · 2506.01812

Two-colour balanced optical cross-correlator using fibre-coupled PPLN waveguides

Jonathan Christie·James R. Henderson·Edward W. Snedden·Laura Corner
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Abstract

We present a two-colour fully fibre-coupled balanced optical cross-correlator (BOXC) based on sum-frequency generation (SFG) between 1560 nm and 800 nm laser pulses using waveguides implemented in type-0 phase-matched periodically poled LiNbO$_{3}$ (PPLN) crystals. The interaction has an effective nonlinear coefficient of $d_{eff}$ = 16.1 pm/V, many times higher than comparable nonlinear crystals used for this SFG interaction such as barium borate (BBO). The resulting sensitivity of the cross-correlator is measured to be 5.11 mV/fs, five times greater than current bulk-optic BOXCs after accounting for differences in transimpedance gain and photodetector responsivity, with the potential for significantly higher sensitivity after optimisations to the cross-correlator design.

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Jonathan Christie, James R. Henderson, Edward W. Snedden, Laura Corner. 2025-06-02. Two-colour balanced optical cross-correlator using fibre-coupled PPLN waveguides. https://arxiv.org/abs/2506.01812

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