Proton-exchanged planar waveguides have been fabricated on Z-cut and X-cut lithium niobate crystals by using a new proton source formed by a mixture of benzoic and adipic acids. Waveguide index profiles and optical characteristics have been obtained at different values of the adipic-benzoic acid concentration ratio. The samples have been structurally characterized by Raman and infrared (IR) absorption spectroscopy and double-crystal X-ray diffraction. Good quality samples have been fabricated by using 30 mol% ratio dilution, showing very, low scattering levels (<0.1 dB/cm), relatively high electrooptic coefficient (r(33) = 0.88 pm/V), and low relative percentage of interstitial protons (26%). The main factor limiting the waveguide optical properties is the substitutional-interstitial proton ratio, which can be easily controlled to produce good quality waveguides. A demonstration of the repeatability of the exchange process in the acid mixture is also provided.
|Titolo:||LiNbO3 optical waveguides formed in a new proton source|
|Data di pubblicazione:||2002|
|Digital Object Identifier (DOI):||10.1109/50.974820|
|Appare nelle tipologie:||1.1 Articolo in rivista|