Detection of Aflatoxin B1 in Food Based on SMF Taper Combined With Fiber Loop Ring Down Technique

In this paper, a fiber sensing system combined with fiber loop ring down (FLRD) technique to detect aflatoxin B
₁
(AFB
₁
) in food is proposed. The single-mode fiber (SMF) taper was set as the sensor head, and the waist diameter of it was determined to be 17.1 μm by the refractive index (RI) measurement experiments. When a light pulse enters and circulates in the fiber loop, it experiences a little loss each time as it passes through the sensor head. The ring-down time of the system would be altered by intensity loss near the sensor head, which is related to the concentration of the AFB
₁
solution. The experimental results showed that the sensitivity of AFB
₁
was -0.755 μ s/(μg/ml) in the concentration range of 0-5 μ g/ml with a precision of 0.016 μg/ml. Compared with other AFB
₁
sensors, the system has the advantages of simple structure, low cost, fast response and insensitive to light source fluctuation.