The ferroelectric crystal lithium niobate (LiNbO3) is an attractive material for a variety of photonics applications due to its excellent electro-optic and nonlinear properties. Another benefit of rare-earth doped LiNbO3 is the easy implementation of low-loss waveguides leading to the development of waveguide amplifiers as well as waveguide lasers. In the past, a great deal of attention was attracted to the development of optically pumped Er3+- and Nd3+-doped LiNbO3 waveguide lasers emitting around the 1.5 μm telecom wavelength range and 1.08 μm, respectively. Up to date, Er- and Nd-doped LiNbO3 channel waveguide lasers with slope efficiencies up to 30 %  and 40 % , respectively, have been reported. However, a further improvement of the laser performance can be achieved by using a ridge waveguide geometry due to the smaller mode fields and improved overlap of modes at different wavelengths as well as the reduction of photorefractive damage.
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