We design and analyze a novel low-loss symmetric Y-branch in Lithium Niobate by heavily annealed proton exchange (APE). In this design, a wide transitional waveguide is used between the input and two S-shape output waveguides, making the field match with the mode in the two output waveguides by intentionally generating second-order mode and radiation. By this method, optical power can be coupled into the two output waveguides with high efficiency. simultaneously , the minimum gap between the two output waveguides is 2.7 microns, thus the stem region of this Y-branch has no sharp taper and the fabrication of the device is easy. The Y-branch is optimized by the method of three-dimensional FD-BPM, after optimization, losses can be less than 0.05dB.

Date Published: 28 August 2002
PDF: 4 pages
Proc. SPIE 4904, Optical Fiber and Planar Waveguide Technology II, (28 August 2002); doi: 10.1117/12.481216

Published in SPIE Proceedings Vol. 4904:
Optical Fiber and Planar Waveguide Technology II
Shuisheng Jian; Steven Shen; Katsunari Okamoto, Editor(s)