Semi-analytical analysis of lithium niobate photonic wires

Lithium niobate (LiNbO3) photonic wires are of growing interest in the field of nonlinear optics and to fabricate micro-ring resonators. In this paper the design and analysis of LiNbO3 photonic wires by a semi-analytical technique is presented. The two-dimensional refractive index profile of the waveguide is transformed into lateral one-dimensional equivalent-index profile by the effective-index method. A transfer matrix method is then applied to this lateral equivalent-index profile of the waveguide to determine the propagation constants and electric-field distributions of the guided modes. Single mode photonic wires at 1.31 μm transmitting wavelength are designed for both TE and TM polarizations and finally, the matrix method is employed along with the conformal mapping technique to determine the bending loss of the curved photonic wires for different radii of curvature. The process needs less computation power, both in terms of elapsed time and memory, and can also be applicable to other photonic materials.