Nonlinearity Measurement of Thin-Film Lithium Niobate Phase Modulator

Optical phase modulator linearity is an important concern for high dynamic range phase modulated (PM) optical links. Due to the linearity advantages of conventional lithium niobate (LiNbO ₃ ) modulators over its semiconductor counterparts, and recent advances in its thin-film implementations, it is of particular interest to understand its associated linearity performance. This article concerns the phase modulator linearity measurement of a thin-film LiNbO ₃ modulator. We present measurement results, measurement limitations, and discuss the dynamic range improvement for a phase modulated optic link that can be enabled by a heterogeneously integrated thin-film LiNbO ₃ modulator.