Amplification combination of Er3+ and Tm3+ emissions in titanium-diffused lithium niobate strip waveguide

Ti:Er:Tm:LN strip waveguide was fabricated by Ti-diffusion following Er3+/Tm3+ co-diffusion. The waveguide supports TE or TM single-mode at 1.5 µm and has a loss < 0.5 dB/cm. Tm3+ codoping effectively promotes the resistance to optical damage. Net gain of 0.8/0.1 dB/cm is obtained for the 1547/1450 nm small signal, showing that Er3+/Tm3+ codoping enables to combine the amplifications of the emissions of both ions. Higher gain is expected by optimizing the fabrication condition and employing a Zr4+-doped NS LN to more effectively withstand the optical damage. The waveguide then has great potential for integrated optics.368