Efficient erbium-doped thin-film lithium niobate waveguide amplifiers

TL;DR

This paper presents a compact, efficient erbium-doped lithium niobate waveguide amplifier demonstrating over 5 dB gain at 1530 nm with low pump power, advancing integrated photonics.

Contribution

The work introduces a novel fabrication process for erbium-doped LNOI waveguides achieving significant on-chip amplification.

Findings

>5 dB net gain at 1530 nm

Low pump power of 21 mW required

Compact 5-mm-long waveguide

Abstract

Lithium niobate on insulator (LNOI) is an emerging photonic platform with great promises for future optical communications, nonlinear optics and microwave photonics. An important integrated photonic building block, active waveguide amplifiers, however, is still missing in the LNOI platform. Here we report an efficient and compact waveguide amplifier based on erbium-doped LNOI waveguides, realized by a sequence of erbium-doped crystal growth, ion slicing and lithography-based waveguide fabrication. Using a compact 5-mm-long waveguide, we demonstrate on-chip net gain of > 5 dB for 1530-nm signal light with a relatively low pump power of 21 mW at 980 nm. The efficient LNOI waveguide amplifiers could become an important fundamental element in future lithium niobate photonic integrated circuits.