Open AccessShallow-etched thin-film lithium niobate waveguides for highly-efficient second-harmonic generation
Author(s) -
Jianhui Zhao,
Michael Rüsing,
Usman A. Javid,
Jingwei Ling,
Mingxiao Li,
Qiang Lin,
Shayan Mookherjea
Publication year - 2020
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.395545
Subject(s) - lithium niobate , materials science , optics , poling , second harmonic generation , waveguide , energy conversion efficiency , optoelectronics , thin film , wavelength , laser linewidth , laser , ferroelectricity , physics , dielectric , nanotechnology
High-fidelity periodic poling over long lengths is required for robust, quasi-phase-matched second-harmonic generation using the fundamental, quasi-TE polarized waveguide modes in a thin-film lithium niobate (TFLN) waveguide. Here, a shallow-etched ridge waveguide is fabricated in x-cut magnesium oxide doped TFLN and is poled accurately over 5 mm. The high fidelity of the poling is demonstrated over long lengths using a non-destructive technique of confocal scanning second-harmonic microscopy. We report a second-harmonic conversion efficiency of up to 939 %.W -1 (length-normalized conversion efficiency 3757 %.W -1 .cm -2 ), measured at telecommunications wavelengths. The device demonstrates a narrow spectral linewidth (1 nm) and can be tuned precisely with a tuning characteristic of 0.1 nm/°C, over at least 40 °C without measurable loss of efficiency.