Open AccessSilicon optical filter with transmission peaks in wide stopband obtained by anti-symmetric photonic crystal with defect in multimode waveguides
Author(s) -
Manuel Mendez-Astudillo,
Hideaki Okayama,
Hirochika Nakajima
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.001841
Subject(s) - stopband , optics , materials science , photonic crystal , optoelectronics , multi mode optical fiber , coupled mode theory , photonic integrated circuit , refractive index , optical fiber , physics , resonator
We experimentally demonstrate and characterize a wide optical stopband filter with transmission peaks constituted by two parallel rows of an anti-symmetric one-dimensional (1D) photonic crystal with defect in a multimode waveguide. The working principle is based on mode coupling for the wavelengths that meet the phase matching condition as the fundamental mode is coupled to a higher-order mode and then filtered out with linear tapers as they are reflected back. The defect in the photonic crystal works as a Fabry-Perot like cavity that allows for localized states in the stopband to quantify the effects of the design parameters and we show a Fabry-Perot filter that extends through the 200 nm stopband. A compact 7 μm 2 device is demonstrated with standard fabrication techniques in Silicon-on-Insulator (SOI), and compared to Fabry-Perot filters in single mode waveguides, we obtain a larger bandwidth and lower back reflections. Applications include refractive index sensors, optical communications and on-chip spectroscopy.