Open AccessPlanar waveguide moiré grating
Author(s) -
Shengping Liu,
Yating Zhou,
Yong Zhao,
Jilin Zheng,
Jun Lu,
Xiangfei Chen
Publication year - 2017
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.024960
Subject(s) - optics , grating , materials science , waveguide , planar , apodization , fiber bragg grating , diffraction grating , semiconductor laser theory , blazed grating , optoelectronics , semiconductor , wavelength , physics , computer science , computer graphics (images)
We propose a new kind of planar waveguide Bragg grating structure, i.e., planar waveguide moiré grating (MG), which is formed by two transverse adjacent gratings with slightly different Bragg wavelengths. It is found that this kind of structure shows the same light properties as the conventional MG that is realized by superimposing two Bragg gratings. Because the proposed MG structure is a planar pattern, the fabrication becomes much easier if applying a semiconductor microfabrication process, which is very beneficial for its applications in photonic integrated devices. Similar to the well-known Vernier effect, the coupling coefficient distribution can be easily adjusted by the alignment of the two adjacent gratings. Consequently, some special grating profiles can be achieved, such as perfect apodization with two sides of the coupling coefficient approaching zero. One important potential application of these specific features is the distributed feedback (DFB) semiconductor laser for improved properties, such as reduced spatial-hole burning and more power extraction. Some design examples are also given in this paper.