High speed phase modulators for silicon photonic integrated circuits: a role for lithium niobate?

Integrating lithium niobate (LN) modulators with other functions on a single optical chip has proven difficult, until the development of thin film LN, which has enabled the development of silicon integrated photonic chips including LN modulators that can operate at very low voltage and at high speed. Recent progress on thin-film LN for high speed modulators is evaluated.