Optical modulators are at the heart of optical communication links. Ideally, they should feature low insertion loss, low drive voltage, large modulation bandwidth, high linearity, compact footprint and low manufacturing cost. Unfortunately, these criteria have only been achieved on separate occasions. Based on a Silicon and Lithium Niobate hybrid integration platform, we demonstrate Mach-Zehnder modulators that simultaneously fulfill these criteria. The presented device exhibits an insertion loss of 2.5 dB, voltage-length product of 2.2 V•cm, high linearity, electro-optic bandwidth of at least 70 GHz and modulation rates up to 112 Gbit/s. The high-performance modulator is realized by seamless integration of highcontrast waveguide based on Lithium Niobate -the most mature modulator material -with compact, low-loss silicon circuits. The hybrid platform demonstrated here allows for the combination of "best-in-breed" active and passive components, opening up new avenues for enabling future high-speed, energy efficient and cost-effective optical communication networks.

We report, to our knowledge, the first dual-polarization thin-film lithium niobate coherent modulator for next-generation optical links with sub-1-V driving voltage and 110-GHz bandwidth, enabling a record single-wavelength 1.96-Tb/s net data rate with ultrahigh energy efficiency.

Growing global data traffic requires high-performance modulators with a compact size, a large bandwidth, a low optical loss, and a small power consumption. A careful trade-off among these parameters usually has to be made when designing such a device. Here, we propose and demonstrate an electro-optic ring modulator on the thin-film lithium niobate platform without compromising between any performances. The device exhibits a low on-chip loss of about 0.15 dB with a high intrinsic quality-factor (Q-factor) of 7.7 × 10 5 . Since a pure coupling modulation is employed, the photon lifetime is no longer a limiting factor for the modulation speed. A large electro-optic bandwidth is obtained without any roll-off up to 67 GHz. The device, with a footprint of 3.4 m m × 0.7 m m , also exhibits a low half-wave voltage of 1.75 V, corresponding to a half-wave voltage length product of 0.35 V ⋅ c m considering the 2-mm-long modulation section. Driverless data transmission up to 240 Gb/s is also demonstrated with a peak-to-peak driving voltage of 0.75 V.

We propose and demonstrate a hybrid silicon and lithium niobate Michelson interferometer modulator (MIM) with a reduced half-wave voltage-length product compared to a Mach-Zehnder modulator. The modulator is based on seamless integration of a high-contrast waveguide based on lithium niobate—a widely used modulator material—with compact, low-loss silicon circuitry. The present device demonstrates a half-wave voltage-length product as low as 1.2 V cm and a low insertion loss of 3.3 dB. The 3 dB electro-optic bandwidth is approximately 17.5 GHz. The high-speed modulations are demonstrated at 32 Gbit/s and 40 Gbit/s with the extinction ratio of 8 dB and 6.6 dB, respectively. The present device avoids absorption loss and nonlinearity in conventional silicon modulators and demonstrates the lowest half-wave voltage-length product in lithium niobate modulators. The hybrid MIM demonstrates high-speed data modulation showing potential in future optical interconnects.

High-performance and compact integrated photonics platform based on silicon rich nitride-lithium niobate on insulator APL Photonics 6, 116102 (2021);