Er:Ti:LiNbO3 ridge waveguide optical amplifiers by optical grade dicing and three-side Er and Ti in-diffusion

摘要

Erbium-doped titanium in-diffused ridge waveguide optical amplifiers in x-cut congruent-LiNbO3 substrates pumped by a 1486 nm laser diode are reported for the first time. High internal gain of 2.7 dB/cm has been demonstrated in 2.5 cm long waveguides for the coupled pump power 200 mW exceeding the best literature values reported for Er: Ti: LiNbO3 channel waveguides. For gain improvement, we have developed a novel technique which is comprised of ridge definition using diamond blade dicing followed by three-side erbium (Er) and titanium (Ti) layer deposition and high-temperature diffusion. Thereby both higher Er concentrations with more symmetric diffusion profiles and lower scattering losses due to the high-temperature smoothened waveguide side walls have been obtained.