title: Electro-optic guided-to-radiation mode conversion in annealed proton-exchanged PPLN waveguides.
abstract: We report the design and experimental demonstration of electro-optically active TM-guided to TE-radiation mode converters in annealed proton-exchanged (APE) periodically poled lithium niobate (PPLN) channel waveguides in telecom S-C-L bands (1495-1640 nm). A maximum mode conversion efficiency of >95%/cm was obtained at 1520 nm from a 24-μm-period APE PPLN waveguide under an electro-optic (EO) field of ~6.3 V/μm at 35°C. This efficiency has been enhanced by a factor of >4.6 over a waveguide built in the single-domain (unpoled) LiNbO3; it is also to the best of our knowledge the most efficient guided-to-radiation (GTR) mode converter ever reported based on LiNbO3 on-axis waveguides. A conversion bandwidth of ~250 nm was also observed from this EO GTR mode converter.
authors.affiliation: Department of Optics and Photonics, National Central University, Jhongli 320, Taiwan.
authors.forename: J W
authors.initials: JW
authors.lastname: Chang
authors.forename: Y H
authors.initials: YH
authors.lastname: Chen
authors.forename: Q H
authors.initials: QH
authors.lastname: Tseng
authors.forename: W K
authors.initials: WK
authors.lastname: Chang
authors.forename: S L
authors.initials: SL
authors.lastname: Deng
authors.forename: C S
authors.initials: CS
authors.lastname: Hsieh