Ardakani Abbas Ghasempour
Appl Opt. 2018 Feb 1;57(4):625-631. doi: 10.1364/AO.57.000625.
We first investigate the propagation of an initially localized optical beam through an ordered waveguide array in which the real part of the refractive index of all waveguides is the same, while there is a linear gradient loss along the transverse direction x. When the optical loss is an increasing function of x, the beam injected into every point of the array propagates to the left edge of the array. But for the case at which optical loss is a decreasing function of x, the optical beam propagates to the right edge of the array. In both cases, as the beam reaches the array edge, it is first reflected by the edge due to the presence of a repulsive potential near the array boundary, and then its width remains constant. We next study the wave propagation through a disordered array of waveguides in which the real parts of the refractive indices of waveguides are random numbers, and there exists a transverse loss gradient. For different random realizations with the same disorder level, when the beam is injected into the central waveguide, the beam becomes localized near the array edge with the lower loss.
我们首先研究初始局域化光束在有序波导阵列中的传播情况，该阵列中所有波导的折射率实部相同，但沿横向x存在线性梯度损耗。当光学损耗是x的增函数时，注入阵列每个点的光束会传播到阵列的左边缘。但对于光学损耗是x的减函数的情况，光束会传播到阵列的右边缘。在这两种情况下，当光束到达阵列边缘时，由于阵列边界附近存在排斥势，它首先会被边缘反射，然后其宽度保持不变。接下来，我们研究波在无序波导阵列中的传播，其中波导的折射率实部是随机数，并且存在横向损耗梯度。对于具有相同无序程度的不同随机实现，当光束注入中心波导时，光束会在损耗较低的阵列边缘附近局域化。
