Tapered depressed-cladding waveguide lasers modulated by Ag nanoparticles embedded in SiO2

• Fabrication of tapered circular depressed-cladding waveguides in Nd:YAG crystal by femtosecond laser direct writing. Demonstration efficient Q -switched mode-locked lasers based on waveguide structures employing silver nanoparticles embedded fused silica as saturable absorber. The influence geometrical parameters guiding properties and performance is studied. We report fabrication writing (FsLDW). Based the fabricated waveguides, for first time to best our knowledge, (QML) are realized (NPs) absorber (SA) element. Laser pulses short 25 ps with a repetition rate 7.7 GHz generated at wavelength 1064 nm. systematically explore incident-output facet reduction factors conducting comparative study different tapers, it has been found that can suppress multi-mode while ensure fundamental-mode output lasers. Our work paves new way toward developing three-dimensional (3D) applications on-chip ultrafast sources.