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Bulgarian Journal of Physics
Print: 1310-0157 Online: 1314-2666
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RECOGNIZED BY THE EUROPEAN PHYSICAL SOCIETY 
Bulg. J. Phys. vol.17 no.3 (1990), pp. 240-248
Fabrication and Characterization of Proton Exchanged Lithium Niobate Planar Optical Waveguides
M., Kuneva1, I. Savatinova1, S. Tonchev1, M. Armenise2
1Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Lenin blvd, Sofia 1784, Bulgaria
2Dipartimento di Elettrotecnica ed Elettronica, Universita di Bari, Via Re David 200, 70125 Bari, Italy
go back1Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Lenin blvd, Sofia 1784, Bulgaria
2Dipartimento di Elettrotecnica ed Elettronica, Universita di Bari, Via Re David 200, 70125 Bari, Italy
Abstract. Proton exchange process in benzoic acid with l% lithium benzoate added is used lo fabricate planar waveguides in LiNbO3. The surface quality of the waveguides obtained is compared with that of samples exchanged in pure benzoic acid. Planar waveguides in Z-cut substrates fabricated at three different temperatures: 210, 220 and 230°C for 7 hours were systematically studied. The diffusion constant Doz and activation energy Ea in the diffusion equation were calculated from the measured effective indices neff and compared with those obtained by other authors in the case of TIPE process and for exchange in pure benzoic acid. The waveguide stability with time is investigated. IR-spectra of virgin LiNbO3 as well as of exchanged layers were recorded and considered as an indicator of the waveguiding effect, waveguide optical quality and parameter stability.