Core-shell LaF₃:Er,Yb nanocrystal doped sol–gel materials as waveguide amplifiers

Abstract

The oleic acid (OA)-modified LaF₃:Er,Yb and LaF₃:Er,Yb–LaF₃ core-shell nanocrystals are synthesized. The lifetime values could be further improved by incorporating core-shell nanocrystals. A kind of sol–gel derived organic–inorganic hybrid material (SGHM) allows for 50 wt.% or even more of both the two nanocrystals in the matrix, and we give the explanation from scattering analysis. It’s precisely because we use the erbium nanocrystals rather than erbium organic complexes, and avoid the undesirable luminescence quenching by Er–Er clustering with a high Er³⁺ concentration. LaF₃:Er,Yb–LaF₃/SGHM transparent films and optical waveguides are also fabricated. The nanocomposite films show strong 1550 nm luminescence intensity under the excitation of 980 nm after heat treatment below 150 °C and the full-width-at-half-maximum is about 51 nm. The loss and optical gain of the waveguide are measured. A relative gain of about 3.5 dB is measured at 1550 nm in a 1.7 cm long waveguide.