Highly sensitive current sensor utilizing CrNi-wire supported microfiber coils

High current sensitivity is obtained based on a microfiber that is wrapping around a chrome-nickel (CrNi) wire. Due to the strong heating effect of the CrNi wire with the flowing electric current, the mode index and the loop length of microfiber are changed, resulting in the shift of resonant wavelength. The measured current responsivity is as high as 220.65nm/A 2 , which is in two or three magnitude orders than the previously-obtained ones. We study the influence of component size to the structure performance, which is useful for future applications of current sensing or tuning devices.