Acousto-optic modulation in lithium niobate on sapphire

Abstract: We demonstrate acousto-optic phase modulators in X-cut lithium niobate films on sapphire, detailing the dependence of the piezoelectric and optomechanical coupling coefficients on the crystal orientation. This new platform supports highly confined, strongly piezoelectric mechanical waves without suspensions, making it a promising candidate for broadband and efficient integrated acousto-optic devices, circuits, and systems.