Research on fiber loop coupled resonator slow light and displacement sensing technology

Slow light technology is becoming a research hotspot because of light-matter interaction enhancement effects, especially sensitivity enhancement effects. This paper theoretically studied the technology of slowing light speed down based on fiber double-loop coupled resonator, which mainly carried on a numerical simulation about the loop loss influence on characteristics of slow light by using iterative and parameter matrix methods. The slow light time delay of 32.0668 ns was achieved in the experimental system. And then a micro-displacement sensing scheme using loop loss and a bending loss modulator was proposed and designed. In order to implement micro-displacement sensing, bending loss effect of single-mode fiber was induced into one loop to produce a controllable loss. Finally, a 2 μm displacement resolution and a 50 ns/mm displacement sensitivity of slow light micro-displacement sensing at the displacement range of 0-350 μm were obtained from the experimental results.