Jiang Mingshun

Refractive index sensor based on plastic optical fiber with tapered structure

This work reports a refractive index sensor made of plastic optical fiber (POF) with tapered structure. Transmission loss is measured when the external environments refractive index changes from 1.33 to 1.41. Three wavelengths (532, 633, and 780 nm) are used to evaluate the sensitivity of the sensor, and results indicate that 633 nm is the best sensing wavelength due to the increased levels of sensitivity achieved at this wavelength. A biconical sensing structure is designed to enhance the sensitivity of the sensor. A sensitivity of 950 μW/RIU at 633 nm is obtained for a biconical sensing structure when launched power is 1 mW. Due to its sensitivity to the refractive index and simple construction, POF with tapered structure has potential applications in the biosensing field.

High-Temperature FBG Sensor and Interrogation System for Aluminum Smelter Cell

An on-line temperature monitoring system is established for aluminum tank shell, and a novel high FBG temperature sensor is designed. There are many shortcomings can not be avoided of traditional detection methods under high magnetic environment. Fiber Bragg grating has advantages of anti-electromagnetic interference and corrosion resistance. It is suitable be used in aluminum tank shell temperature monitoring. Combining with optical time division multiplexing (TDM) and wavelength division multiplexing (WDM) technology, a complete system consists of 104 FBG sensors is designed. FBG sensor temperature range is −20~400 °C, with temperature accuracy +2 °C. Measured data of the system provide reliable real-time basis for the process control and condition diagnosis.

Sensitivity-Tunable FBG Interrogation System Utilizing a Mechanically Induced Long Period Fiber Grating

A mechanically induced long-period fiber grating (MLPFG) scheme and a sensitivity tunable fiber Bragg grating (FBG) interrogation system is presented. The MLPFG is made by pressing a plate with periodic grooves (which were fabricated using mechanical line processing technology) against a short length of single mode fiber. The strength of that resonant band of MLPFG is altered by applying pressure to the fiber. A FBG whose center-wavelength is localized on the slope of a resonant band of a mechanical grating is chosen. By applying a pressure with a value from 20 N to 60 N on the MLPFG, the FBG is submitted to strain values of up to 3000 μe, during which the Bragg wavelength and the respective transmitted peak power through the MLPFG are recorded. It is demonstrated that the sensitivity of this FBG interrogation system to strain variations increased from 0.802 nW/μe to 1.204 nW/μe.