To study the photonic-crystal fiber applied in the chemical sensor, the photonic-crystal fiber was used as transmission
medium. With Sol-Gel method, we selective coated thin film containing fluorescent probe in the photonic-crystal fiber
core, then attained an excellent photonic-crystal fiber acetylcholinesterase sensor. The sensor could be applied in
biological / chemical research, clinical medicine, environmental protection, food inspection, biochemical preventive war
field and so on. In organophosphorus pesticide residue testing, the experimental results indicated that the linear
measurement range could arrive to 1×10-9~ 1×10-3 mol/L, moreover the detection limit is 1×10-10 mol/L.