Ultra sensitive NH3 gas detection using microfiber Bragg Grating

In this paper, a microfiber Bragg grating (MFBG) is proposed and performed to detect ammonia gas directly with high sensitivity. The sensor is fabricated by etching Fiber Bragg grating (FBG) inscribed in a single mode photosensitive optical fiber. The response of the sensor for ammonia gas detection is studied by experiments. The result shows that the MFBG central wavelength red-shift occurs as the ammonia gas concentration increase. The experimental concentration detection sensitivity is about 171 pm/(mg/L) in range of 21.84-43.68 mg/L. And the sensor is insensitive for several possible interfering volatile organic compounds.