Strengths indicates a good agreement among them. The absorption band 4I15/2→2H11/2 located at 521 nm is more intense than the other bands, so called as higher sensitive transition which sensitive to environment even small changes around the Ln3+ ions. Itis remarkable the wide absorption band for 4I13/2 in line with similar glasses like TWZEr [25], which is advantageous for some non- linear processes like UC [32].