Research on cholesterol solution sensor based on tilted fiber Bragg grating

Detecting cholesterol content is an important auxiliary method for clinical diagnosis of various cardiovascular diseases. In this work, we experimentally demonstrate a high-sensitivity tilted-fiber-Bragg-grating (TFBG) sensor for detecting cholesterol solution with a targeted concentration range of 0.2–4.0 mg/mL. The TFBG embedded in fiber core enables a strong coupling between multiple cladding modes and core mode, generating plenty of resonance peaks in the transmission spectrum for sensing the index change of external environment. The results show that the resonance peak exhibits a good linear relationship (~ 0.12 nm/(mg/mL)) with the concentration of cholesterol solution, and the resonance wavelength is red-shifted with the increase of the concentration. Through temperature-sensing experiments, it is proved that the thermal sensitivity of the core mode and the cladding mode is roughly similar with a value of ~ 8.0 pm/℃. Accordingly, the temperature-induced interference in the concentration-sensing process can also be eliminated in practical application. This study provides a new simple method for the high-efficiency measurement of cholesterol solution and has great potential in the detection of fat soluble solution.