An Integrated Photonic Platform for Rare-Earth Ions in Thin Film Lithium Niobate

TL;DR

This paper presents a new integrated photonic platform using thin film lithium niobate doped with Tm3+ ions, enabling efficient on-chip optical devices with preserved ion properties and lower power requirements.

Contribution

It demonstrates the successful incorporation of rare-earth ions into a thin film lithium niobate platform with optical properties comparable to bulk crystals, advancing integrated quantum and classical photonics.

Findings

Optical lifetimes of ions in thin film match bulk crystal values.

Narrow spectral holes are generated with significantly lower power.

Platform enables scalable on-chip lasers and quantum memories.

Abstract

Rare-earth ion ensembles doped in single crystals are a promising materials system with widespread applications in optical signal processing, lasing, and quantum information processing. Incorporating rare-earth ions into integrated photonic devices could enable compact lasers and modulators, as well as on-chip optical quantum memories for classical and quantum optical applications. To this end, a thin film single crystalline wafer structure that is compatible with planar fabrication of integrated photonic devices would be highly desirable. However, incorporating rare-earth ions into a thin film form-factor while preserving their optical properties has proven challenging. We demonstrate an integrated photonic platform for rare-earth ions doped in a single crystalline thin film on insulator. The thin film is composed of lithium niobate doped with Tm3+. The ions in the thin film exhibit optical lifetimes identical to those measured in bulk crystals. We show narrow spectral holes in a thin film waveguide that require up to 2 orders of magnitude lower power to generate than previously reported bulk waveguides. Our results pave way for scalable on-chip lasers, optical signal processing devices, and integrated optical quantum memories.