Study On Tandem Optical Parametric Oscillation And Amplification Technology Based On MgO:Ppln Crystal

Tandem OPO and OPA technique based on a single block of one periodical MgO: PPLN crystal is an effective way to get high-power broadband tunable mid-infrared laser. In this thesis, we mainly to design a Tandem Optical Parametric Oscillator based on a single block of one periodical MgO:PPLN crystal which pumped by a high repetition rate acousto-optical Q-switched Nd:YVO4lasers.Firstly, based on the QPM technology and the OPO principle, Theoretically simulated the wavelength tunability by changing temperature and grating of MgO:PPLN crystal,built the five wavelength coupling equation,analyzed the quantum conversion efficiency of TOPO.Secondly bulit the heat conduction equation of tandem OPO+OPA based on MgO: PPLN crystal,gave the physical model of the temperature distribution in crystal,analyed the thermal effects in crystal.Then,for the degenerate points of tandem process, completed the design of the mid-infrared laser.Finally,obtained the output power21W at repetition rate50kHz, the pulse width is13.64ns,the peak power is30.8kW.The pump power is10.93W, obtained the single wavelength1.702μ m, and the degenerate wavelength2.837μm at temperature81℃the grating period is31.5μm. Obtained the single wavelength1.704u m and the degenerate wavelength2.834μm at temperature192.1℃the grating period is31.0μm, the experimental values are consistent with the theoretical calculations.The total power under the two grating and temperature is3.0W and2.459W, the conversion efficiency is27.4%and22.5%,respectively, higher than the ordinary OPO.