Integration of a GaAs-based nanomechanical phase shifter with quantum-dot single-photon sources

Abstract: We demonstrate a small-footprint electromechanical phase shifter with a compact active length of $10:\mu \text{m}$ fabricated on a suspended GaAs membrane, offering versatile integration with quantum-dot single-photon sources. The phase shifter is based on a slot-mode waveguide, whose slot width can be controlled by electrostatic forces, enabling a large effective refractive index change $\Delta n_\text{eff} > 0.1$. We observe up to 3$\pi$ phase modulation with 10.6 \text{V} applied bias, and a figure of merit $V_{\pi}L = 5.7\cdot 10^{-3} \text{V}\cdot \text{cm}$. Integration with a Mach-Zehnder interferometer (MZI) further allows routing of single photons with up to 24 \text{dB} extinction ratio at cryogenic temperatures. This device enables advanced manipulation of quantum emitters and the realization of reconfigurable quantum photonic integrated circuits.