Title :
A Highly Sensitive Fiber-Optic Refractive Index Sensor Based on an Edge-Written Long-Period Fiber Grating
Author :
Zhu, Tao ; Rao, Yun-Jiang ; Jiu-Ling Wang ; Song, Yun
Author_Institution :
Chongqing Univ., Chongqing
Abstract :
A novel long-period fiber grating (LPFG) is edge-written without any destructive damage on the fiber based on the thermal shock and rapid cooling effects of the high-frequency CO2 laser pulses exposure method in this letter. The refractive index disturbance induced by high-frequency CO2 laser pulses mainly occurs in the edge region of the fiber cladding rather than in the fiber core. An edge-written LPFG with a resonant peak of ~18 dB is obtained using a standard telecommunication fiber. The experimental results show that such a novel LPFG structure has much higher refractive index sensitivity over conventional LPFGs side-written, which can be used as a refractive index sensor, or a tunable filter and modulator by controlling the refractive index sensitive film which is coated on the cladding of such an LPFG.
Keywords :
Bragg gratings; cooling; fibre optic sensors; refractive index; thermal shock; edge-written long-period fiber grating; fiber cladding; fiber-optic refractive index sensor; high-frequency laser pulses; modulator; rapid cooling; refractive index disturbance; telecommunication fiber; thermal shock; tunable filter; Cooling; Electric shock; Fiber gratings; Fiber lasers; Optical fiber sensors; Optical pulses; Refractive index; Resonance; Telecommunication standards; Tunable circuits and devices; CO$_{2}$ lasers; long-period fiber gratings (LPFGs); optical fiber sensors; refractive index measurement;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2007.908777