  High bandwidth, low voltage electro-optic modulators with high optical power
handling capability are important for improving the performance of analog
optical communications and RF photonic links. Here we designed and fabricated a
thin-film lithium niobate (LN) Mach-Zehnder modulator (MZM) which can handle
high optical power of 110 mW, while having 3-dB bandwidth greater than 110 GHz
at 1550 nm. The design does not require etching of thin-film LN, and uses
hybrid optical modes formed by bonding LN to planarized silicon photonic
waveguide circuits. A high optical power handling capability in the MZM was
achieved by carefully tapering the underlying Si waveguide to reduce the impact
of optically-generated carriers, while retaining a high modulation efficiency.
The MZM has a $V_\pi L$ product of 3.1 V$.$cm and an on-chip optical insertion
loss of 1.8 dB.
