Chunyang Han

Magnetic Field Sensor Based on Microfiber Sagnac Loop Interferometer and Ferrofluid

We demonstrate a novel compact optical magnetic field sensor composed of a single-mode microfiber sagnac loop interferometer (SMSLI) and ferrofluid (FF). The refractive index of FF cladding in the twist area of SMSLI is changed with the externally applied magnetic field, which makes the dip-wavelength of the SMSLI transmission spectra shift. The experimental results show that the transmission spectrum of the proposed sensor shifts regularly with the change of externally applied magnetic field intensity. When the magnetic field intensity increased from 0 to 600 Oe, the dip-wavelength of transmission spectrum shifted nearly 200 pm. In addition, a minimal detectable magnetic field strength of the sensor responding to the 50-Hz alternating magnetic field was demonstrated to be ~3 Oe experimentally.

Demonstration of a refractometric sensor based on an optical micro-fiber three-beam interferometer

With diameter close to the wavelength of the guided light and high index contrast between the fiber and the surrounding, an optical micro-fiber shows a variety of interesting waveguiding properties, including widely tailorable optical confinement, strong evanescent fields and waveguide dispersion. Among various micro-fiber applications, optical sensing has been attracting increasing research interest due to its possibilities of realizing miniaturized fiber optic sensors with small footprint, high sensitivity, and low optical power consumption. Typical micro-fiber based sensing structures, including Michelson interferometer, Mach-Zenhder interferometer, Fabry-Perot interferometer, micro-fiber ring resonator, have been proposed. The sensitivity of these structures heavily related to the fraction of evanescent field outside micro-fiber. In this paper, we report the first theoretical and experimental study of a new type of refractometric sensor based on micro-fiber three-beam interferometer. Theoretical and experimental analysis reveals that the sensitivity is not only determined by the fraction of evanescent field outside the micro-fiber but also related to the values of interferometric arms. The sensitivity can be enhanced significantly when the effective lengths of the interferometric arms tends to be equal. We argue that this has great potential for increasing the sensitivity of refractive index detection.

A novel magnetic field sensor based on the combination use of microfiber knot resonator and magnetic fluid

In this paper, a novel all-fiber magnetic field sensor based on a device consisting of microfiber knot resonator (MKR) and magnetic fluid (MF) is proposed for the first time. MF is infused into a homemade sealed cell containing a partially embedded MKR in low-index polymer as sensing element. Experimental results show that the resonance wavelength of the proposed sensor regularly varies with changes of the applied magnetic field. When the magnetic field increases to 22mT, the wavelength shift reaches nearly 200pm.

A NOVEL ALL-FIBER ELECTRIC FIELD SENSOR BASED ON TAPERED FIBER-SLAB WAVEGUIDE COUPLER

In this paper, a novel all-fiber electric field sensor based on tapered fiber-slab waveguide coupler was proposed for the first time. Experiments were implemented for investigating the dependences of TFSC transmission features on their geometries parameters. On the base of that a TFSC based sensor with optimal construction parameters and sharper coupling spectra were fabricated. The nearly linear relationship between the changes of sensor outputs and the external applied electric field are demonstrated by experiments. The minimal detectable of electric field has also been demonstrated experimentally to be ~50V/cm.

An all-fiber electric field sensor based on tapered fiber-slab waveguide coupler

In this paper, a novel all-fiber electric field sensor based on tapered fiber-slab waveguide coupler was proposed for the first time. Experiments were implemented for investigating the dependences of TFSC transmission features on their geometries parameters. On the base of that a TFSC based sensor with optimal construction parameters and sharper coupling spectra were fabricated. The nearly linear relationship between the changes of sensor outputs and the external applied electric field are demonstrated by experiments. The minimal detectable of electric field has also been demonstrated experimentally to be ∼50V/cm.