Active waveguides in LiNbO3

In Integrated Optics (IO), LiNbO3 is a well known material, widely used to realize very efficient electro-optic integrated devices for telecommunication such as phase modulators, intensity modulators and directional couplers. But, with the availability of good quality rare earth doped material and the perfecting of a new waveguide fabrication technique, Proton Exchange (PE), a completely different set of active devices are now possible. The common factor of these devices is that they take advantages of the high optical power resistance of the PE waveguides, of the amplification due to the rare earths, and, of the electro-optic/nonlinear properties of the crystal. In this paper the authors present: an optical pumped CW amplifier in Nd:MgO:LiNbO3 offering up to 8 dB small signal gain at λ = 1.085μm; an optically pumped CW laser in Nd:MgO:LiNbO3 emitting 14 mW at λ = 1.085μm with a slope efficiency of 34% and a threshold of 2.7 mW; an FM Mode-locked waveguide laser in Nd:MgO:LiNbO3 realized by electro-optically driving the laser at the cavity round-trip frequency emitting 8 ps pulses of 250 mW peak power with a 6.2 GHz repetition rate; a self doubled waveguide laser in Nd:MgO:LiNb3 emitting some hundreds of μW in the blue (SHG of the pump and mixing the pump with the laser frequency) and the green (SHG of the laser wavelength)