Nd : MgO : LiNbO_3 和Er : Ti : LiNbO_3 波导激光器的理论研究

THEORETICAL STUDY OF Nd∶MgO∶LiNbO 3 AND Er∶Ti∶LiNbO 3 WAVEGUIDE LASERS

首次报导了Ｎｄ∶ＭｇＯ∶ＬｉＮｂＯ３和Ｅｒ∶Ｔｉ∶ＬｉＮｂＯ３波导激光器的理论研究结果．对于Ｎｄ∶ＭｇＯ∶ＬｉＮｂＯ３质子交换波导激光器，通过假设在波导宽度／深度方向上模场强度分布为Ｇａｕｓｓｉａｎ／Ｈｅｒｍｉｔｅ－Ｇａｕｓｓｉａｎ和Ｇａｕｓｓｉａｎ／Ｔｗｏ－ｈａｌｆ－Ｇａｕｓｓｉａｎ两种试探函数，给出了阈值泵浦功率和斜率效率的计算结果．对于钛扩散Ｅｒ∶Ｔｉ∶ＬｉＮｂＯ３波导激光器，利用变分法计算了光波导信号和泵浦光模场强度分布高斯参数和有效折射率随波导条宽的变化关系，还计算了相应的有效泵浦面积与信号光及泵浦光之间的耦合效率．此外，直接从Ｅｒ∶Ｔｉ∶ＬｉＮｂＯ３光波导的荧光光谱计算了Ｅｒ３＋的受激发射截面，并计算了Ｅｒ∶Ｔｉ∶ＬｉＮｂＯ３波导激光器的阈值泵浦功率和斜率效率．

The theoretical results of Nd∶MgO∶LiNbO 3 and Er∶Ti∶LiNbO 3 waveguide lasers have been presented.For annealed proton exchange Nd∶MgO∶LiNbO 3 waveguide lasers,by assuming Gaussian/Hermite Gaussian and Gaussian/two half Gaussian mode intensity distributions in the direction of width/depth of the waveguide,the threshold pump power and slope efficiencies were calculated and compared with experimental results.For Ti diffused Er∶LiNbO 3 waveguide lasers,Gaussian parameters,effective refractive indices,effective pump area and coupling efficiency as function of the initial Ti stripe width were numerically calculated for respectively 95 and 100 nm initial Ti stripe thickness.In addition,the stimulated emission cross section of Er 3+ in Er∶LiNbO 3 waveguide were calculated directly from its fluorescence spectra using β τ method,and the calculated results of the threshold pump power and slope efficiency were given.