Efficient 1.54 μm laser property in near- stoichiometric Er:LiNbO3 crystal

• Near-stoichiometric Er:LiNbO3 crystal was grown by Czochralski technique.
• The strongest 1.54 μm emission is observed for Er:NSLN crystal.
• Judd–Ofelt parameters based on UV–vis-infrared absorption spectra are discussed.
• Absorption/emission cross-section and fluorescence lifetimes are reported.
• Gain cross-section spectra in the eye-safe regime of 1450–1650 nm are studied.

Near-stoichiometric LiNbO3 crystal heavily doped with Er3+ ions (Er:NSLN) was grown by Czochralski technique. An enhancement of 1.54 μm emission and a lengthening lifetime of 4I13/2→4I15/2 transition observed in Er:NSLN crystal would meet the requirement of the greatly shortening optical diffusion route for Er-doped waveguide amplifiers (EDWAs). Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentration of Er3+ ion in the crystal. Based on Judd–Ofelt theory, the spectroscopic properties of Er:NSLN crystal were discussed, and the obtained intensity parameters Ωt implied that the increased [Li]/[Nb] ratio had a large influence on the value of Ω2. The emission cross-sections of 1.54 μm emission were calculated by Füchtbauer–Ladenburg and reciprocity methods. Studies on the gain cross-section, estimated as a function of the population inversion ratio, suggested that Er:NSLN crystal could be considered as a potential material in the application of the tunable lasers around 1.54 μm wavelength.