Engineering cm-scale true push-pull electro-optic modulators in a suspended GaAs photonic integrated circuit platform by exploiting the orientation induced asymmetry of the Pockels r₄₁ coefficient

Electro-optic modulators (EOMs) underpin a wide range of critical applications in both classical and quantum information processing. While these devices have been extensively optimized in a wide range of materials from ferroelectric insulators like lithium niobate to semiconductors like gallium arsenide and indium phosphide, there is a need to explore new design and manufacturing methods with a view towards improving device performance. Here, we demonstrate true push-pull EOMs in a suspended GaAs photonic integrated circuit (PIC) platform by exploiting the orientation induced asymmetry of the Pockels r₄₁ coefficient, and folding the two arms of a cm-scale Mach–Zehnder interferometer (MZI) modulator along two orthogonal crystal axes. Our work also shows the potential of incorporating ideas from micro-electro-mechanical systems (MEMS) in integrated photonics by demonstrating high-performance active devices built around cm-scale suspended waveguides with sub-µm optical mode confinement.