Temperature characteristics for surface acoustic wave in annealed proton-exchanged LiNbO/sub 3/ waveguides

Chien-Chuan Cheng Chien-Chuan Cheng,Ying-Chung Chen Ying-Chung Chen,Kuo-Sheng Kao Kuo-Sheng Kao

doi:10.1109/isaf.2002.1195954

Chien-Chuan Cheng Chien-Chuan Cheng, Ying-Chung Chen Ying-Chung Chen + Show 1 more

https://doi.org/10.1109/isaf.2002.1195954

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Abstract

The temperature characteristics for surface acoustic wave (SAW) in annealed proton-exchanged (APE) LiNbO/sub 3/ waveguides were investigated. The process performed by immersing z-cut LiNbO/sub 3/ substrates in pure octanoic acid was experimentally studied. The penetration depth of hydrogen assumed to be equal to the waveguide depth (d) was measured by secondary-ion mass spectrometry (SIMS). The annealing process was carried out in a horizontal furnace kept at 400/spl deg/C for 4 h under a dry O/sub 2/ gas flow. The velocity (V/sub p/) and temperature coefficient of frequency (TCF) of SAW measured by a network analyzer were observed. The results showed that the V/sub p/ and TCF in APE LiNbO/sub 3/ samples tended to improve in comparison with the PE LiNbO/sub 3/ samples. It exhibited that the annealing effect could result in a restoration of the decreased V/sub p/ and an improvement of TCF. However, the values of TCF in APE LiNbO/sub 3/ samples were larger than that of the unexchanged one.

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