Remote sensing based on reflective bandpass long-period fiber grating and fiber ring laser

Abstract

A remote sensing system based on bandpass long-period fiber grating (LPFG) and fiber ring laser is proposed in this paper. The reflective bandpass LPFG is fabricated by fusion splicing a piece of hollow core fiber (HCF) to the LPFG.And the fiber ring laser is employed to narrow the line-width of the bandpass LPFG and realize remote sensing. As an application example, a temperature experiment is conducted at the spot more than 1 km away from the fiber ring laser.The experimental results show that such a sensor has a sensitivity of 0.0254nm/°C within the range of 20-150°C.

Sensing and Demodulation of Special Long-Period Fiber Gratings Induced by ScanningCO2Laser Pulses

“…However, the inherent broad bandwidth of the LPFG limits the precision of measurements when the measurement is realized by means of wavelength shift. Recently, a remote sensing system based on LPFG and fiber ring laser is presented [65]. The stopband in the transmission spectrum of the LPFG is inverted into a pass-band by fusion splicing a piece of HCF to the grating.…”

“…Then such an inverted LPFG is employed in the master and slave ring laser, in which the grating is used as the wavelength selector and sensor head simultaneously. The temperature experiment shows that such a system can measure the temperature more than 1 km away and the sensitivity is ∼0.02 nm/ • C within the range of 20-150 • C. The remote sensing schematic diagram is shown in Figure 21 [65]. The LPFG with band pass characteristics working in the reflective mode is used as sensor and band pass filter simultaneously, which is shown schematically in Figure 22(a).…”