Watt-level SHG in undoped high step-index PPLN ridge waveguides

Vincent Pecheur,Henri Porte,Mathieu Chauvet,Moise Deroh,Jérôme Hauden,Florent Bassignot

doi:10.1364/osac.420448

Abstract

Nonlinear quadratic waveguides are key components to obtain efficient frequency conversion. In this paper we present the performances of highly multimode periodically poled lithium niobate (PPLN) ridge waveguides for high power CW SHG are presented. We report the generation of 1 W of second harmonic on the fundamental guided mode with a conversion efficiency of 56% at telecom wavelengths. A stable nonlinear process is obtained despite use of an undoped congruent LiNbO3 crystal. The input damage threshold of the ridge waveguide is found to set the maximum usable power.

Highlights

Optical frequency conversion is of interest for various domains such as astronomy where parametric upconversion from mid infrared to visible range is exploited for efficient detection [1, 2], for life science imaging and analysis of interfaces details [3,4] or for medical or safety applications based on spectroscopy in the terahertz range [5, 6]
Quantum technologies have strong interest in nonlinear optical materials especially for generation of entangled pairs of photons [7, 8] and for cooling atoms [9,10,11]. The latter applications typically rely on CW watt level sources that take advantage of the mature technology of telecommunication components in combination with efficient frequency conversion devices to shift the wavelength to the requested value by second harmonic generation (SHG)
We have shown that highly multimode ridge periodically poled lithium niobate (PPLN) waveguides designed for SHG of telecom wavelengths give stable generation of over 1W output power in CW regime with an efficiency of 56%

Summary

Introduction

Optical frequency conversion is of interest for various domains such as astronomy where parametric upconversion from mid infrared to visible range is exploited for efficient detection [1, 2], for life science imaging and analysis of interfaces details [3,4] or for medical or safety applications based on spectroscopy in the terahertz range [5, 6]. Quantum technologies have strong interest in nonlinear optical materials especially for generation of entangled pairs of photons [7, 8] and for cooling atoms [9,10,11] The latter applications typically rely on CW watt level sources that take advantage of the mature technology of telecommunication components (tunable near infrared sources, modulators, optical amplifiers) in combination with efficient frequency conversion devices to shift the wavelength to the requested value by second harmonic generation (SHG). Such SHG devices are often based on Lithium Niobate (LiNbO3) crystals thanks to its high nonlinear second order coefficient, large transparency window and wavelength conversion versatility using the quasi-phase matching process. The influence of the PR effect is analyzed along with the maximum usable power

Design and Fabrication

Optical characterization

Objective

Findings

Conclusion