Hybrid Lithium Niobate Research Articles

Design of an ultra-low mode volume piezo-optomechanical quantum transducer.

Coherent transduction of quantum states from the microwave to the optical domain can play a key role in quantum networking and distributed quantum computing. We present the design of a piezo-optomechanical device formed in a hybrid lithium niobate on silicon platform, that is suitable for microwave-to-optical quantum transduction. Our design is based on acoustic hybridization of an ultra-low mode volume piezoacoustic cavity with an optomechanical crystal cavity. The strong piezoelectric nature of lithium niobate allows us to mediate transduction via an acoustic mode which only minimally interacts with the lithium niobate, and is predominantly silicon-like, with very low electrical and acoustic loss. We estimate that this transducer can realize an intrinsic conversion efficiency of up to 35% with <0.5 added noise quanta when resonantly coupled to a superconducting transmon qubit and operated in pulsed mode at 10 kHz repetition rate. The performance improvement gained in such hybrid lithium niobate-silicon transducers make them suitable for heralded entanglement of qubits between superconducting quantum processors connected by optical fiber links.

Hybrid Silicon and Lithium Niobate Modulator

Hybrid Lithium Niobate (LN) and Silicon photonic (SiPh) integration platform has emerged as a promising candidate to combine the scalability of silicon photonics with the excellent modulation performance of LN. Mach-Zehnder modulators (MZMs) based on this platform exhibit outstanding performance with low insertion loss, low drive voltage, and large bandwidth. In this paper, we discuss the technologies for realizing hybrid LN/SiPh platform. The configuration and key metrics of LN/SiPh MZM are analyzed in detail. Furthermore, various functional devices derived from the Mach-Zehnder interferometer (MZI) configuration are also reviewed.

Vertical mode transition in hybrid lithium niobate and silicon nitride-based photonic integrated circuit structures.

This Letter presents an optical mode transition structure for use in Si3N4/LiNbO3-based hybrid photonics. A gradual modal transition from a Si3N4 waveguide to a hybrid Si3N4/LiNbO3 waveguide is achieved by etching a terrace structure into the sub-micrometer thick LiNbO3 film. The etched film is then bonded to predefined low pressure chemical vapor deposition Si3N4 waveguides. Herein we analyze hybrid optical devices both with and without the aforementioned mode transition terrace structure. Experimental and simulated results indicate that inclusion of the terrace significantly improves mode transition compared to an abrupt transition, i.e., a 1.78 dB lower mode transition loss compared to the abrupt transition. The proposed transition structure is also applied to the design of hybrid Si3N4-LiNbO3 micro-ring resonators. A high-quality factor (Q) resonator is demonstrated with the terrace transition which mitigates undesired resonances.