Fig. 3: Measurements of cross-correlation coefficients. | npj Quantum Information

Fig. 3: Measurements of cross-correlation coefficients.

From: Towards a spectrally multiplexed quantum repeater

Fig. 3

a Simplified Tm level scheme. b Measurement sequence. c A trench in the Tm absorption profile used to filter the signal modes. d 5 × 5 cross correlation coefficients measured with a VIPA array, 5 SNSPDs and a Tm:LiNbO3 filter e 89 cross correlation coefficients on a 20 × 20 grid of signal and idler spectral modes, measured using a single collection fiber and only the 6.1 GHz cavity filter for the 795 nm photons. Panels (d) and (e) use the same heatmap to indicate the value of \({{\rm{g}}}_{s,i}^{(2)}\).

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