The optical properties of Er3+ doped LiNbO3, LiNbO3(MgO) and LiNbO3(Zn
O) have been studied. Polarized absorption and laser excited luminesce
nce spectra at liquid-He temperature show different structure dependen
t on the co-dopants (MgO, ZnO). The relationship between the optical c
haracteristics and the impurity sites location is discussed.