Improvement of optical characteristics of silicon based 1×3 beam splitter with photonic crystal waveguide

Abstract

In this work, we propose a new structure of 1×3 beam splitter with photonic crystal (PhC) waveguide in order to improve their optical characteristics such as higher optical transmission power and lower losses. At first, we design a two dimensional (2D) triangular lattice structure consisting of circular air holes drilled in a silicon slab for 1550 nm of wavelength. Then, we use a structure in Y-junction waveguides with a large separating angle for designing a photonic crystal 1×3 beam splitter. The proposed 1×3 beam splitter consists of two different 1×2 beam splitters. The first 1×2 beam splitter has an unequal power distribution with two splitting ratios of 1/3 and 2/3 in both output ports. In this first splitter, we have introduced a Drop Houl defect in their distribution zone for having unequal division. The second one is a 1×2 beam splitter with an equal power distribution. Finally, the optical characteristics of the modified structure of photonic crystal 1×3 beam splitter are numerically analyzed by FDTD method. The obtained results show that the proposed photonic crystal 1×3 splitter has a total of transmission efficiency about 92% at 1550 nm and 1573 nm, respectively. An equal power distribution has been obtained about 31% in each output power. The proposed splitter also exhibited a transmission loss lower than 10%.