Fig. 2: Architecture, optical fanout, and modulator performance.
From: An integrated photonic engine for programmable atomic control
a An incident s-polarization hologram produced by a Fourier-domain SLM couples to many transverse electric (TE) waveguide modes via grating couplers (i–iii; c). Integrated MZIs impart programmed waveforms on each channel. Output grating couplers direct light, now p-polarized, back to free-space towards the target sites (iv). For better visibility, four channels—rather than the full sixteen—are shown in this diagram. b, A top-down view of our setup illustrates the lenses and objectives omitted from the simplified diagram in a. The half-waveplate in front of the objective aligns the beamsplitter and grating polarization axes. A double-4f lens configuration, with one lens participating in both 4fs, enables large fields of view. White dots represent imaging or Fourier planes. c The 1 × 16 input and d, the 4 × 4 output grating coupler arrays on our device in white light (i) and under coherent excitation (ii), showing the WGS-generated fanout hologram (c ii) and the resulting uniform output beams (d ii). Scalebars represent 50 μm. e Several iterations of WGS yield peak-to-peak optical output power errors σpk-pk of ~1% and standard deviations σstd of~0.1%. f Wirebonding to a PCB connects each of our sixteen channels to external control electronics. The scalebar represents 500 μm. g, Switching bandwidth of a modulator channel. h A trace of device transmission versus voltage.
