Optical absorption and emission properties of Nd3+-doped fluorophosphates glass for broadband fiber amplifier applications

Abstract

A new series of fluorophosphate glass is developed which can be doped with an extremely high concentration of Nd³⁺. The dependence of the optical absorption and emission properties on dopant concentration is reported here for the concentration range 2.5×10²⁰ to 1.25×10²¹ ions/cm³. Absorption and emission measurements are performed in order to evaluate the spontaneous emission probability, absorption cross-section, emission cross-section, and laser performance parameters. We have synthesized two glass systems: MBBA/NdI with an Nd³⁺ concentration of 2.50×10²⁰ cm³ and MBBA/NdII with an Nd³⁺ concentration 6.26×10²⁰ cm³. The stimulated emission cross sections are 1.14 and 1.64×10⁴ cm² for the ⁴F_3/2→⁴I_13/2 transition and 3.68 and 6.68×10⁴ cm² for the ⁴F_3/2→⁴I_13/2 transition in MBBA/NdI and MBBA/NdII, respectively. Similarly, the extraction efficiencies are measured to be 1.91, 2.31 (⁴FI_3/2→⁴I_13/2) and 6.18, 9.41 (⁴F_3/2→⁴I_11/2) in MBBA/NdI and the MBBA/NdII, respectively. This new (Mg, Ba)F₂-based fluorophosphate glass (MBBA system) is promising for broadband compact optical fiber and waveguide amplifier applications.