Figure 4. Hong–Ou–Mandel interference between TE0 and TE1.

(a) Schematic of asymmetric grating to couple even to odd modes. The period (Λ) is 8 μm, the number of periods (N) is 8 and the grating depth, d, is 24 nm. The width, w, is 1,010 nm and the height is 190 nm. This corresponds to a splitting ratio η=0.64. (b) We show the coincidence rate (accidentals subtracted) of the two output arms as we delay one input arm. The red line is a Gaussian fit to the experimental data. The HOM visibility is 78±0.3%. The error bars indicate standard error of measurement.