K(+)-Na+ ion-exchanged waveguides in Er(3+)-Yb3+ codoped phosphate glasses using field-assisted annealing

Buried channel waveguides were fabricated in Er(3+)-Yb3+ codoped phosphate glasses with use of the thermal two-step ion-exhange method. The K(+)-Na+ ion-exchange process was first carried out in pure KNO3 molten bath, and then field-assisted annealing (FAA) was used to make the buried waveguides. The fluorescence properties of bulk glasses and channel waveguides were characterized, and the waveguide properties were studied. The formation mechanism of buried waveguides was analyzed, and the improved gain characteristics of the waveguide amplifiers with use of different FAA temperatures were measured. The maximum net gain of the waveguide amplifiers at 1.534-microns wavelength was measured to be approximately 3.4 +/- 0.1 dB/cm with 120-mW pump power at 975-nm wavelength.