Characterization of optical properties and laser behavior in Yb3+/Al3+ co-doped microstructure optical fiber

A microstructure optical fiber with Yb 3 + /Al 3 + co-doped glass core is fabricated using high-temperature laser sintering process combined with stack-capillary-draw technology. No crystal is observed in the core glass and its fluorescence lifetime is measured to be 1.31 ms. The bonding features of glass and fiber, together with the structure of fiber core and cladding, are provided and analyzed. Moreover, the uniform element distributions and the axial stress profiles show a highly symmetrical variation trend which is in good agreement with the intensity distribution of Raman signal in Micro-Raman mapping. Excited by 976-nm LD, the laser slope efficiency of microstructure optical fiber reaches up to 72.5 % at 1032 nm. The near-field beam intensity distribution of fiber laser with spectrum FWHM of 8 nm exhibits an excellent laser beam quality. This work strongly suggests Yb 3 + /Al 3 + co-doped silica preform fabricated by high-temperature sintering method is applicable for the field of high-power laser.