Silicon On-Chip One-Dimensional Photonic Crystal Nanobeam Bandgap Filter Integrated With Nanobeam Cavity for Accurate Refractive Index Sensing

A novel method for integration of high-performance 1-D photonic crystal nanobeam bandgap filter (1-D PC-NBF) and high-sensitivity 1-D PC nanobeam cavity sensor (1-D PC-NCS) is proposed on a monolithic silicon chip. The 1-D PC-NBF consists of a simple 1-D PC nanobeam waveguide, in which the bulk air-...

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Bibliographic Details
Main Authors: Daquan Yang, Chuan Wang, Yuefeng Ji
Format: Article
Language:English
Published: IEEE 2016-01-01
Series:IEEE Photonics Journal
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Online Access:https://ieeexplore.ieee.org/document/7422659/
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Summary:A novel method for integration of high-performance 1-D photonic crystal nanobeam bandgap filter (1-D PC-NBF) and high-sensitivity 1-D PC nanobeam cavity sensor (1-D PC-NCS) is proposed on a monolithic silicon chip. The 1-D PC-NBF consists of a simple 1-D PC nanobeam waveguide, in which the bulk air-hole grating radii are kept the same. The 1-D PC-NCS consists of a common 1-D PC nanobeam cavity, in which the air-hole grating radius is parabolically tapered from center to end. By using the 3-D finite-difference time-domain (3-D-FDTD) method, the proposed 1-D PC-NBF with an effective low-pass bandgap ranging from 1533 to 1785 nm (with width &#x003E; 250 nm) is demonstrated, where the resonant wavelengths lying in the bandgap are not guided. Then, by connecting an additional 1-D PC-NBF to a 1-D PC-NCS in series, a transmission spectrum only containing the specific fundamental mode of the 1-D PC nanobeam cavity for sensing purposes is created, while the other high-order modes are filtered out. Moreover, the additional 1-D PC-NBF has no influence on the properties (e.g., <inline-formula> <tex-math notation="LaTeX">$Q$</tex-math></inline-formula>-factor, resonance position, and sensitivity) of the fundamental resonant mode of 1-D PC-NCS. In particular, the footprint of the proposed 1-D PC nanobeam integrated sensor is ultracompact around <inline-formula> <tex-math notation="LaTeX">$0.7\ \mu\text{m}\times 10\ \mu\text{m}$</tex-math></inline-formula>, which is improved more than three orders of magnitude compared with the integrated sensor devices based on 2-D PC. Thus, the method presented here is promising to build highly parallel integrated sensor arrays for lab-on-a-chip applications and accurate detections.
ISSN:1943-0655