The development of laser technology has created intense demand for optical confinement materials with high performance. Herein the authors have been investigated Yb 3+ -singly doped and Yb 3+ /Nd 3+ -codoped SiO 2 -based oxyfluoride glasses in terms of their optical absorption, and their near-infrared (NIR) and up-conversion (UC) emissions including emission decay profiles. Under 808 nm laser diode (LD) excitation, four NIR emission bands were observed i.e., (Nd 3+ : 4 F 3/2 → 4 I 9/2 , Yb 3+ : 2 F 5/2 → 2 F 7/2 , Nd 3+ : 4 F 3/2 → 4 I 11/2 , and Nd 3+ : 4 F 3/2 → 4 I 13/2 ) in co-doped glasses. NIR emission cross-sections [ (σ emi ) stimulated, (σ M emi ) from Mc-cumber theory] were calculated for 2 F 5/2 → 2 F 7/2 (∼1030 nm) transition of Yb 3+ ion. σ emi was found to be highest (26.27 × 10 −21 cm 2 ) for the Yb 3+ : 2 F 5/2 → 2 F 7/2 transition in N2 glass. UC emission spectra recorded at 980 nm LD show bands centered at 500, 536, 595 & 610, and 664 nm, attributed to 4 G 9/2 → 4 I 9/2 , 4 G 7/2 → 4 I 9/2 & 4 G 7/2 → 4 I 11/2, 4 G 5/2 → 4 I 9/2 , and 4 G 9/2 → 4 I 13/2 transitions, respectively. Decay profiles were analyzed for Yb 3+ : 2 F 5/2 → 2 F 7/2 (∼1030 nm) and Nd 3+ : 4 F 3/2 → 4 I 11/2 (∼1057 nm) transitions at 808 nm LD. Energy transfer (ET) process from Nd 3+ to Yb 3+ in present glasses were detailed.