Tubular depressed cladding waveguide laser realized in Yb: YAG by direct inscription of femtosecond laser
Abstract
We report on the fabrication of tubular depressed cladding waveguides in single crystalline Yb:
YAG by the direct femtosecond laser writing technique. Full control over the confined light
spatial distribution is demonstrated by the photoinscription of high index contrast waveguides
with tubular configuration. Under optical pumping, highly efficient laser oscillation in depressed
cladding waveguide at 1030 nm is demonstrated. The maximum output power obtained is
68mW with a slope efficiency of 35% for an outcoupling transmission of 50%. A slope
efficiency as high as 44% is realized when the coupling output ratio is 91% and a low lasing
threshold of 70mW is achieved with the output coupling mirror of 10%.