Study On Photoluminescence And Optical Gain Properties Of Er/Yb Co-doped Borate-silicate Glasses

Er-doped glass has been payed much attention, due to the transition ⁴I_13/2â†'⁴I_15/2 of Er³⁺ can generate 1.53μm photoluminescence which correspond to the maximum transparency of silica-based optical fibers. Nowadays, maximizing the optical properties of Er³⁺ becomes a hotspot. Er/Yb co-doped system has been found to be an effective method toenhance the gain due to the excellent sensitizing ability of Yb³⁺. Therefore, it is of importance to study the photoluminescence properties of Er/Yb co-doped system in various glasses.In this dissertation, Er/Yb co-doped borate-silicate glass with 0.5 molï¼…Er₂O₃ were fabricated by solid reaction method. The concentration of Yb₂O₃ was in the range of 0.0 molï¼…to 5.5 molï¼…. The absorption and photoluminescence (PL) spedctra, together with the lifetime of Er³⁺-⁴I_13/2 were measured.The major points of this work are summarized as follows:The absorption cross section of Er³⁺ were calculated, due to the absorption spedctra.The sensitizing effect of Yb³⁺ has been approved and the Yb³⁺ co-doping effect on the absorption spedctra of Er³⁺ has been researched.The optical parameters such as Judd-Ofelt intensity parameter and radiative lifetime of Er³⁺-⁴I_13/2 were calculated by Judd-Ofelt theory. Using Judd-Ofelt intensity parameter, we analyzed the local environment of Er³⁺ in the glass.The dependence of PL intensity on Yb³⁺ concentration has been investigated and the broadening of PL spectra owing to the increasing of Yb³⁺ has been observed. With the purpose of finding the factors affecting the PL properties, we measured the up-conversion specta and calculated the energy transfer rate between Er³⁺ and Yb³⁺ by Inokuti-Hirayama exchange mechanism. Also, the dependence of the particle population on the Er³⁺-⁴I_13/2 level on Yb₂O₃ concentration was studied.In order to investigate the gain property of Er/Yb co-doped waveguide amplifier, the rate equation model for Er/Yb co-doped system and the propagation equation of the waveguide have been established based on the first-handed data obtained from the measurements. The dependence of optical gain on Yb₂O₃ concentration, pump power, waveguide length and waveguide loss are studied by solving these two equation.