| dc.description.abstract | LiNbO3 has higher nonlinear, electro-optic coefficient and ferroelectric property. We could fabricate a single chip with more capability. By using ferroelectric property and lithography, we can develop the periodically inverted domain, Using the nonlinear coefficient, we can generate any wavelength of laser. Using the electro-optic coefficient, we can produce Q-switched pulse laser. For reduce the effect of photorefractive, we choose MgO:LiNbO3 crystal to improve it. Appling the theory of quasi-phase matching and the fabrication of periodically poled, and combination with low loss optic waveguide, we can get high efficiency of second-harmonic generation (SHG) for green light laser.
We successfully fabricate these 18 um 3rd period domain inverse with 5mol/% Mg-doped Linbo3 substrate, the duty cycle about 50%. This paper makes a comparison among three kind of waveguide, Anneal proton exchange, Soft proton exchange, Reverse proton exchange. Conversion efficiency of soft proton exchange waveguide is about 20%W^(-1) cm^(-2), anneal proton exchange waveguide is about 30%W^(-1) cm^(-2). Due to the depth of the soft proton exchange waveguide not quite enough, coupling efficiency become low. If we increase proton exchange time, can improve this situation.It is predicted that conversion efficiency of SPE waveguide would better than APE waveguide. There is a dead layer result in APE waveguide fabrication process, meanwhile destroy nonlinear coefficient. Due to the bad fiber to waveguide coupling efficiency, therefore scattering of fundamental light and noise were detected to reduce it in the measurement. we will have better result by improving the measurement.
In fabrication the reverse proton exchange waveguide, it will cause the crystal-destroyed. We supposed that the more hydrogen ions accumulate the more crack will occur in crystal when the annealing processed therefore, we proposed some of new fabrication method to improve this situation
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