We investigate an aluminum nitride (AlN)-silicon hybrid platform to enable AO modulation on silicon waveguides. The AO interaction is enhanced through a Fabry–Perot resonant cavity, achieving a π-phase shift voltage (V_π) of 27.8 V and a half-wave voltage-length product (V_πL) of 0.55 V·cm with a modulation length of 200 μm. We also demonstrate AO modulation under cryogenic conditions, where the device performance metrics improve to 16.5 V and 0.33 V·cm, respectively. Fabricated using complementary metal-oxide-semiconductor-compatible processes, this AlN-silicon device offers seamless integration with photonic and electronic components, underscoring its potential for next-generation photonic systems.