Fig. 20: Demonstrated OPAs with mode confinement enhancement techniques.

a with photonic crystal separation, [i] aperture composition, [ii] crosstalk simulation, [iii] zoom-up of the fabricated aperture, [iv] far-field pattern; (b) with metamaterial cladding, [i, ii] layout and SEM of the grating aperture; (c) with thicker silicon layer, [i] Simulation and [ii, iii] measurement of waveguide crosstalk of different thickness.