A novel density sensor based on high-birefringence fiber loop mirror

In this paper, a novel density sensor based on high-birefringence fiber loop mirror is proposed and studied. The high-birefringence fiber is pasted to a ring shaped rubber gasbag and placed in the liquid. Fasten the gasbag to the bottom of the container. When the density of liquid is changed, the liquid level keeps the same. The change of the pressure outside the gasbag leads to the variation of the volume of the air in the gasbag. Eventually, the strain of high-birefringence fiber varies with the variation of the volume of the air and the transmittance of high-birefringence fiber loop mirror shifts with the density change. The experimental result indicates that the shifts of wavelengths are in good linear relationship with the density of liquid. The experiment shows that the sensitivity is 8.024nm/(kg/m(3)). The novel density sensor has the advantages such as high sensitivity, polarization independent, low cost and good repeatability.