Optical damage resistant Ti-diffused Zr/Er-codoped lithium niobate strip waveguide for high-power 980 nm pumping

Ti 4+ -diffused Zr 4+ /Er 3+ -codoped LiNbO 3 strip waveguide was fabricated on an X-cut LiNbO 3 substrate by thermal diffusion in sequence of Er 3+ , Zr 4+ and Ti 4+ . Secondary ion mass spectrometry study shows that the Ti 4+ ions follow a sum of two error functions in the width direction and a Gauss function in the depth direction of the waveguide. Both Er 3+ and Zr 4+ profiles follow the desired Gauss function, and entirely cover the Ti 4+ profile. Optical study shows that the waveguide is TE or TM single mode at 1.5 μm wavelength, and has a loss of 0.3 (0.5) dB/cm for the TM (TE) mode. In the case of 980 nm pumping, the waveguide shows stable 1547 nm signal output under high-power pumping without optical damage observed, and a net gain of 1.1 dB/cm is obtained for the available pump power of 120 mW.