Hydrogen-/fluorine-passivation effects in amorphous silica fiber

Highlights: • We provide passivation calculation with H/F in silica fiber. • H/F form robust SiH/SiF bond which can improve electro optic properties. • F is the better passivator combined with electro optic properties. We present first-principles combined GW and Bethe-Salpeter equation on passivation effect between ODC(I) and H/F atoms. The injection of H or F atoms help to form the robust SiH or SiF bond which increase the optical band gap, erase the defect state of ODC(I) at 0.74 eV and improve radiation toughness. The reaction of ODC(I) defect with a H atom or F atoms is barrierless, the SiO length near the ODC(I) sites are all gradually getting shorter and bond energy are getting stronger. Coupled with the atomic structures and electro-optic properties, we found out that F is the better passivator.