S. Steinberg et al., COMPARISON OF PHOTOREFRACTIVE-INDEX CHANGES IN ANNEALED-PROTON-EXCHANGED CHANNEL WAVE-GUIDES IN MGO-DOPED AND CONGRUENT LINBO3, Optics letters, 20(7), 1995, pp. 683-685
A quantitative comparison of the photorefractive effect in annealed pr
oton-exchanged channel waveguides in MgO-doped and congruent LiNbO3 at
the wavelengths of 633 and 830 nm is presented. An accurate measureme
nt technique is described to measure the refractive-index change as a
function of time and the guided mode intensity for different wavelengt
hs. The results show that doping with 7% MgO reduces the photorefracti
ve effect at a wavelength of lambda = 633 nm by 2 orders of magnitude.
The photorefractive effect in the doped substrate shows only a weak d
ependence on the guided power. Doping with 4 mol.% MgO has only little
effect on the photorefractive effect compared with that on the congru
ent material. A reduced photovoltaic current is responsible for the sm
all photorefractive effect in the 7 mol.%-doped substrate.