Inverse nanotapers and lensed fibers for highly efficient coupling

Because it is not possible to integrate the light source on the silicon-based photonic chips, it is necessary to study the efficient coupling method to coupling the light from the fiber into the chip. In order to ensure the high coupling efficiency, the edge coupling method is adopted in this paper. The simulation is carried out in the COMSOL software. The incident light is set as a Gaussian beam with a waist diameter of 2.5 μm and a wavelength of 1550 nm to simulate the light emitted from the lensed fiber. The incident region of the waveguide adopts an inverse-nanotaper design, that is along the direction of light propagation, the width and height of the waveguide in the taper region gradually increase and keep constants in the bus waveguide region. In this paper, the specific size of the designed inverse-nanotaper coupler is given, and the coupling efficiency of the edge couplers under different conditions is analyzed, which lays a certain foundation for on-chip integration of related devices.