A theoretical study of a Ti-diffused Er:LiNbO/sub 3/ waveguide laser

A detailed theoretical procedure of determining the mode sizes of fundamental mode field distribution in a coaxially pumped Ti-diffused Er:LiNbO/sub 3/ waveguide laser has been described. The mode sizes, effective refractive indexes, effective pump area, and coupling efficiency as a function of the initial Ti stripe width W were numerically calculated for the waveguide with 95- and 100-nm initial Ti stripe thicknesses, respectively. The results indicated that the threshold pump power is severely affected by the stripe width, while slope efficiency is hardly changed as W; both show little difference between 95- and 100-nm stripe thickness. In addition, the stimulated emission cross section of Er/sup 3+/ in Er:LiNbO/sub 3/ channel waveguide versus the wavelength were calculated directly from its fluorescence spectra using the /spl beta/-/spl tau/ method. Subsequently, threshold pump power and slope efficiency were evaluated.