一维光学格子孤子的传输特性及控制研究

利用解析和数值方法研究了在具有横向折射率周期性调制的克尔型非线性介质中光学格子孤子的传输，得到了孤子参数的演化方程以及格子孤子的形成和稳定传输的条件.结果表明：当光束的入射角小于某临界角度时，光束可被类似波导形式的路径俘获而稳定传输，该临界角随折射率调制周期、调制深度的增加而增大，且光束越窄临界值越大.此外，线性空间啁啾虽然对光束传输的中心位置没有任何影响，但会导致光束发散从而破坏格子孤子的形成和稳定传输，对此提出了采用特定功率取值来补偿啁啾作用从而形成格子孤子的方案. 关键词： 光孤子 光学格子 光传输 矩方法

Study of propagation characteristics and control of one-dimensional optical lattice soliton

Propagation of optical lattice soliton in nonlinear Kerr medium with harmonic modulation of refractive index is investigated analytically and numerically. The equations governing evolution of the soliton parameters and the conditions for soliton formation and stable propagation are obtained. It is shown that the beam is finally trapped in a guide-like channel and propagates stably when the launching angle is smaller than a critical value. The critical angle increases as the depth and period of modulation of refractive index increase, and increases as the beam width decreases. Furthermore, linear spatial chirp upsets the balance between diffraction and nonlinearity, thus affects the formation and stable propagation of the soliton, although it doesn't affect the central position of the beam. In order to maintain the soliton propagation one can offset the effect of the chirp by using proper beam power.