In this work, we presents the refractometric sensor based multimode optical fiber with titanium dioxide (TiO₂) coating for measurement of the refractive index change of bulk media. The phase retardation, which is induced by the TiO₂ coated optical fiber, was measured by homodyne detection system. The results show that the sensor detection limit was experimentally achieved around 5.67 × 10⁻⁸ (RIU) with an operating refractive index range of 7.5 × 10⁻⁵ (RIU), obtained at single operating wavelength of 632.8 nm without using spectroscopic techniques. Those features, with the sensor merits of highly sensitive device, have led to potential applications for biomedical and biochemical detection in label-free manner.

在这项工作中，我们提出了基于折光传感器的多模光纤，带有二氧化钛 (TiO ₂ ) 涂层，用于测量体介质的折射率变化。通过零差检测系统测量由TiO ₂涂层光纤引起的相位延迟。结果表明，在不使用光谱技术的情况下，在 632.8 nm 的单一工作波长下获得的传感器检测极限在实验上达到约 5.67 × 10 ^-8 (RIU)，工作折射率范围为 7.5 × 10 ^-5 (RIU)。这些特征以及高灵敏度设备的传感器优点，已导致以无标记方式进行生物医学和生化检测的潜在应用。