Paper
28 June 2013 Single-helix chiral long period fiber gratings for wavelength-interrogated liquid level sensing
Author Affiliations +
Abstract
We develop coupled-mode formulism for multimode couplings of LP01 core modes to LP1n cladding modes in singlehelix chiral long-period fiber gratings (S-CLPG). Then mode-coupling characteristics of the structure, such as coupling coefficients and relative bandwidths of dips are studied and compared with those of the conventional long-period fiber grating (LPG). Subsequently, transmission spectral characteristics in response to the liquid level are investigated for SCLPG partially immersing in a liquid with refractive index lower than that of the fiber cladding. Simulation results indicate that the dips corresponding to the multimode couplings in the transmission spectrum will shift continuously and monotonically as liquid level changes. Thus S-CLPG could be used for liquid level sensing based on wavelength interrogation, which is beneficial to avoid sensitivity deterioration caused by power instability in power interrogation for most conventional LPG-based liquid level sensors. In addition, we identify that the sensitivity can be enhanced with a thinner fiber cladding or by utilizing higher-order cladding mode resonance. The optimization result indicates that the wavelength shift will be over 1.03 nm per millimeter liquid level change.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Li Yang and Yunfei Wu "Single-helix chiral long period fiber gratings for wavelength-interrogated liquid level sensing", Proc. SPIE 8561, Advanced Sensor Systems and Applications V, 85610B (28 June 2013); https://doi.org/10.1117/12.999607
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Cladding

Liquids

Refractive index

Sensors

Structured optical fibers

Etching

Resonance enhancement

Back to Top