Optical Fiber Laser Salinity Sensor Based on Multimode Interference Effect

An optical fiber laser salinity sensor based on multimode interference effect is proposed and demonstrated. The sensor head manufactured by splicing a section of no-core fiber (NCF) between two single-mode fibers possesses a transmission peak at a certain wavelength due to multimode interference effect. Salinity of the liquid it immerges can be measured from wavelength shift the transmission peak. Enhanced measurement accuracy is achieved by inserting the sensor head into the cavity of an erbium-doped fiber ring laser, because the laser’s linewidth is much narrower than that of the transmission peak. Linear response with salinity sensitivity of 19.4 pm/% has been achieved and the measurement range is from 3.86% to 21.62%.

[1]  A. Castillo Guzman,et al.  Widely tunable erbium-doped fiber laser based on multimode interference effect , 2010 .

[2]  R. C. Kamikawachi,et al.  Salinity measurement in water environment with a long period grating based interferometer , 2009 .

[3]  J E Antonio-Lopez,et al.  Fiber-optic sensor for liquid level measurement. , 2011, Optics letters.

[4]  L. Nguyen,et al.  Three-Wave Fiber Fabry–Pérot Interferometer for Simultaneous Measurement of Temperature and Water Salinity of Seawater , 2011, IEEE Photonics Technology Letters.

[5]  A. Mehta,et al.  Multimode interference-based fiber-optic displacement sensor , 2003, IEEE Photonics Technology Letters.

[6]  P. LiKamWa,et al.  Tunable multimode-interference bandpass fiber filter. , 2010, Optics letters.

[7]  Kangsheng Chen,et al.  Fiber optic Bragg grating sensor based on hydrogels for measuring salinity , 2002 .

[8]  Hwa-Yaw Tam,et al.  Salinity sensor based on polyimide-coated photonic crystal fiber. , 2011, Optics express.

[9]  Orlando Frazão,et al.  Refractometric sensor based on a phase-shifted long-period fiber grating. , 2006, Applied optics.

[10]  E. M. Stanley.  The refractive index of seawater as a function of temperature, pressure and two wavelengths☆ , 1971 .

[11]  P. Lu,et al.  A multiplexed fiber Bragg grating sensor for simultaneous salinity and temperature measurement , 2008 .

[12]  N. Díaz-Herrera,et al.  In situ salinity measurements in seawater with a fibre-optic probe , 2006 .

[13]  E.C.M. Pennings,et al.  Optical multi-mode interference devices based on self-imaging: principles and applications , 1995 .

[14]  Qiang Wu,et al.  High sensitivity SMS fiber structure based refractometer--analysis and experiment. , 2011, Optics express.

[15]  J V Moloney,et al.  Detailed investigation of self-imaging in large-core multimode optical fibers for application in fiber lasers and amplifiers. , 2008, Optics Express.

[16]  Q. Han,et al.  Fiber ring laser interrogated zeolite-coated singlemode-multimode-singlemode structure for trace chemical detection. , 2012, Optics letters.

[17]  Orlando Frazão,et al.  Industrialization of advanced optical technologies for environmental monitoring , 2010 .