本讲介绍了强度调制式传感器的各种机理。这些机理包括：光传输、光反射、光纤微弯曲，吸收、荧光、偏振光与光栅。在介绍机理的同时，给出了不同传感器的结构和传感器的输出曲线，这些曲线可作为光纤传感器设计时的参考。本节最后还讨论了强度调制式光纤传感器误差的主要来源，并指出克服误差的方法。 This talk describes the various mechanisms of intensity-modulated sensors. These mechanisms include: light transmission, light reflection, fiber microbending, absorption, fluorescence, polarization and grating. In introducing the mechanism at the same time, given the structure of different sensors and sensor output curve, these curves can be used as a reference fiber optic sensor design. This section also concludes with a discussion of the main sources of error in intensity-modulated optical fiber sensors and points out ways to overcome them.