Dependence of Ti-diffused Er:LiNbO/sub 3/ laser efficiency on waveguide fabrication parameters and pump wavelength

The mode size, effective pump area, and coupling efficiency as function of initial Ti-stripe width W, diffusion temperature T, and initial Ti-stripe thickness H in c-cut Ti-diffused Er:LiNbO/sub 3/ waveguide laser have been studied theoretically, taking into account optical pumping /spl lambda//sub p/=1.477 /spl mu/m and 0.98 /spl mu/m. The main features of the mode sizes in terms of these diffusion parameters were collected and, as compared with the experimental results, a qualitative agreement has been achieved. The effective pump areas exhibit both significant initial Ti-stripe width and diffusion temperature dependence, especially for W>9 /spl mu/m and T>1050/spl deg/C, whereas the initial Ti-stripe thickness can hardly give influence when pumping with /spl lambda//sub p/=0.98 /spl mu/m radiation. On the other hand, coupling efficiency is approximately unchanged with values 0.76-0.78 for /spl lambda//sub p/=1.477 /spl mu/m and 0.8-0.85 for /spl lambda//sub p/=0.98 /spl mu/m, indicating that there are no optimized values of these parameters to increase slope efficiency through coupling efficiency. Moreover, the 0.98 /spl mu/m pumping reveal lower threshold and higher coupling efficiency than 1.477-/spl mu/m pumping. Finally, the appropriate waveguide fabrication parameters were proposed for the fabrication of a more efficient laser.