Optimization of the buffer layer of a side-polished fiber-slab coupler based on a 3-d alternating direct implicit beam propagation method

The buffer layer of a side-polished fiber-slab coupler was optimized by using a 3-dimensional alternating-direction implicit (ADI) beam propagation method, where the refractive index and the thickness of the buffer layer and the distance between the fiber core and the buffer layer for effective coupling were gained by tuning. For a buffer layer thickness of 0.4μm, a refractive index of the buffer layer of 1.4675, and a distance between the fiber core and the buffer layer of 0.9 μm, we were able to achieve maximum coupling.