Regulating emission in Er doped silicate glass and fiber via coordination engineering

L-band Er doped fiber (EDF) laser sources are in great demand for extending communication bandwidth. However, the gain performance is limited by the low emission cross section ( σ e ) of Er 3+ at wavelengths longer than 1590 nm. In our study, we revealed the mechanism of regulating Er emission behavior in silicate glass, and provided a linear model to predict the σ e of Er-doped silicate glass with R 2 = 92.3%. The σ e1600 was increased to 23.5 × 10 −22 cm 2 through erbium coordination engineering. Results were elucidated using X-ray absorption fine structure (XAFS) spectra, molecular dynamics (MD) simulations and fluorescence. Furthermore, this work validates this model in Er doped silicate fibers and obtained >20 dB amplification in the range of 1585–1625 nm. This coordination engineering shows significant potential in applications of Er-doped silicate glasses and fibers. It provides an attractive prospect for expanding communication bandwidth by efficiently manipulating the emission of erbium to cover long wavelength. • Atomic-scale elucidation of Er 3+ L-band emission dynamics was achieved via EXAFS and MD. • Next-nearest neighbor structural modulation was identified as the dominant factor. • An emission cross-section-field strength regulation model was constructed with accuracy of 92 %. • Coordination-engineered optical fiber amplification at L band was demonstrated.