Regular Article

Electro-optic properties of singly and doubly doped lithium niobate crystal by rare earth elements for optoelectronic and laser applications

¹ Institute for Physical Researches, National Academy of Sciences of Armenia, Ashtarak-2, Armenia
² Armenian State Pedagogical University, Yerevan, Tigran Mets Ave. 17, Yerevan, Armenia
³ Laboratoire Matériaux Optiques, Photonique et Systèmes, LMOPS, EA 4423, Université de Lorraine, 57070 Metz, France
⁴ Laboratoire Matériaux Optiques, Photonique et Systèmes, LMOPS, CentraleSupelec, Université Paris-Saclay, 57070 Metz, France

^* e-mail: aillerie@metz.supelec.fr

Received: 29 October 2018
Received in final form: 27 February 2019
Accepted: 6 March 2019
Published online: 26 April 2019

Abstract

Congruent lithium niobate (LN) doped with rare-earth elements is a promising host for integrated optic combining the properties straightforwardly associated to the dopant with the good electro-optic (EO) properties. By direct technique based on interferometric optical arrangement at a wavelength of 633 nm and at room temperature, we have experimentally determined the figure of merit F = n³r_eff, (n is the refractive index and r_eff, the effective EO coefficient) and finally calculated the EO coefficients r_eff of the third-column of the unclamped EO tensor of three series of singly doped LN with Yb³⁺, Ho³⁺, Tm³⁺ and two series of doubly doped Er³⁺–Yb³⁺. It is found that in all the studied opto-geometric configurations, the unclamped figure of merit and consequently the corresponding EO coefficients are relatively constant in the considered dopant concentration range. As the figure of merit, F qualifies crystals for EO modulation and laser applications, all reported results confirm that the LN singly or doubly doped with rare-earth elements are very promising versatile candidates for several multifunctional nonlinear devices in optoelectronic and laser applications.