  Integrated photonics operating at visible-near-infrared (VNIR) wavelengths
offer scalable platforms for advancing optical systems for addressing atomic
clocks, sensors, and quantum computers. The complexity of free-space control
optics causes limited addressability of atoms and ions, and this remains an
impediment on scalability and cost. Networks of Mach-Zehnder interferometers
can overcome challenges in addressing atoms by providing high-bandwidth
electro-optic control of multiple output beams. Here, we demonstrate a VNIR
Mach-Zehnder interferometer on lithium niobate on sapphire with a CMOS
voltage-level compatible full-swing voltage of 4.2 V and an electro-optic
bandwidth of 2.7 GHz occupying only 0.35 mm$^2$. Our waveguides exhibit 1.6
dB/cm propagation loss and our microring resonators have intrinsic quality
factors of 4.4 $\times$ 10$^5$. This specialized platform for VNIR integrated
photonics can open new avenues for addressing large arrays of qubits with high
precision and negligible cross-talk.
