Broadband amplification and upconversion luminescence properties of Er3+/Yb3+ co-doped fluorophosphate glass

Broadband and upconversion properties were studied in Er3+/Yb3+ co-doped fluorophosphate glasses. Large Ω6 and Sed/(Sed+Smd) values and the flat gain profile over 1530-1585 nm indicate the good broadband properties of the glass system. And a premise of using Ω6 as a parameter to estimate the broadband properties of the glasses is proposed for the first time to our knowledge. Results showed that fluorescence intensity, upconversion luminescence intensity, the intensity ratio of red/green light (656 nm/545 nm) are closely related to the Yb3+:Er3+ ratio and Er3+ concentration, and the corresponding calculated lifetime of 4F9/2 and 4S3/2 states for red and green upconversion samples proves this conclusion. The upconversion mechanism is also discussed.