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Please find the appropriate data in the relevant CSV format:

"Figure 1. Down conversion efficiency" 

"Figure 2. Coincidence measurements at 2.1um"

"Figure 3. Two-photon interference" 



Figure 1A: Characterization of the spontaneous down conversion efficiency in a 50 nm bandwidth centred at the 2090 nm degenerate emission wavelength. (A) Shows that the estimated conversion efficiency in the linear regime is of the order of 3.0±0.2×10-11 (input power of 10 mW). The conversion efficiency is not constant and grows with the input power as expected in a nonlinear fashion (see text). The black dashed line is a fit of the conversion efficiency based on the simple model mentioned in the text. The light grey dashed curves indicate the 95% prediction bounds. 



Figure 1B: In (B) we show the measured number of photons generated for input powers up to 1 W. The dashed line is based on the fit in (A).



Figure 2B: Measured coincidence to accidental ratio (CAR) as a function of the averaged single count rates between detector 1 and 2.  The red curve is a fitted CAR based on the model detailed in the text.



Figure 3B: The observed two-photon interference (HOM dip) where the dots represent the experimental two-fold coincidence counts, and the solid curve is the fit to the experimental data (see Materials and Methods for details). Errors were estimated assuming Poisson statistics.