Thermo-optic dispersion formula for the ordinary wave in 5 mol% MgO doped LiNbO3 and its application to temperature insensitive second-harmonic generation

•High accuracy Sellmeier equation for the 5 mol% MgO doped LiNbO3 is presented.•High accuracy thermo-optic dispersion formula for the 5 mol% MgO doped LiNbO3 is presented.•We found that MgO:PPLN has the temperature insensitive SHG points for the first time.

We report the high accuracy thermo-optic dispersion formula for the ordinary wave of 5 mol% MgO doped congruent LiNbO3 (MgO:LiNbO3), which reproduces well our experimental data for the temperature-dependent birefringent phase-matching (BPM) and quasi-phase-matching (QPM) conditions with the oo–e, oo–o, and oe–o interactions in the 0.41–3.7 μm range. In addition, we found the temperature insensitive quasi-phase-matched second-harmonic generation (QPM/SHG) points exist in periodically poled MgO:LiNbO3 (MgO:PPLN) with the oo–o and oe–o interactions for the first time.