DETECTION OF MAGNETIC FIELD BY OPTICAL FIBER MAGNETIC FIELD SENSOR

摘要

PURPOSE:To improve the variance of Verdet's constant due to temperature by making two light beams different in wavelength incident on an optical fiber magnetic field sensor and detecting the Faraday rotation angle for each wavelength. CONSTITUTION:Light beams from a light source 1 which emits light having a wavelength lambda1 and a light source 2 emits light having a wavelength lambda2 are made incident on an optical fiber 4 through a multiplexer 3. They are converted to parallel rays of light by a rod lens 5 and are turned by a rectangular prism 6 and are made incident on a polarizing prism 7. The incident light is converted to linear light and is made incident on a Faraday rotating element 8. The exit light is divided into (x) and (y) components by a polarizing beam splitter prism 9. Light of the (y) component is made incident on an optical fiber 11 by a rod lens 10 and is inputted to a demultiplexer 12. This light is divided to light beams having wavelengths lambda1 and lambda2 again by the demultiplexer 12, and they are made incident on detectors 13 and 14. Light of the (x) component is turned by a rectangular prism 15 and is converted to parallel rays of light by a rod lens 16 and is made incident on an optical fiber 17 and is inputted to a demultiplexer 18. This light is divided into light beams having wavelengths lambda1 and lambda2 again by the demultiplexer 18, and they are made incident on detectors 19 and 20.