Application Research Of Optical Fiber White-light Interferometry

With the rapid development of science and technology,people’s requirements for intelligent production and life are constantly improved.Sensor measurement technology is an important link in the development of social intelligence and network,and the requirements of its measurement accuracy,system stability,technical reliability and service environment are constantly improved.Therefore,it is more and more urgent to develop mature and reliable sensing and measurement technology.Optical fiber sensors have been widely used in the aviation industry,petroleum industry,nuclear power industry,space exploration industry and other advanced scientific and technological fields due to their high measurement accuracy,stable performance,strong anti-interference ability and other excellent characteristics.The appearance of optical fiber white-light interference technology makes optical fiber sensing technology gradually enter the production and life of ordinary people,due to its outstanding characteristics such as high measurement accuracy,simple structure,low light source requirements and strong scalability,it has been widely used in sensor research and development,measurement and testing industry,biomedicine and other fields.In this paper,a single point/quasi-distributed optical fiber pressure sensor is designed based on optical fiber white light interferometry technology of optical path difference modulation,the sensor adopts the elastic cylinder wrapped by optical fiber as the pressure sensing unit,which has the characteristics of remote measurement,multiplexing,adjustable measurement accuracy and range,simple structure and low price.The experimental results show that the pressure sensor has a measuring range of 0⁶00N and a sensitivity of0.0415mm/N under the specific structure design.In this paper,a kind of optical fiber temperature sensor is designed based on optical fiber white-light interferometry technology of optical path difference modulation.The sensor uses single-mode optical fiber as the temperature sensing unit,and the piezoelectric ceramic column wrapped by optical fiber as the optical path scanning unit of reference optical path.Through the further experiment shows that the temperature sensor in 34⁷0℃within the scope of the sensitivity of 2.978 V/℃,and by changing the temperature sensing element and reference light path optical path scanning unit structure design can meet different measuring range and accuracy requirements.Based on the principle of optical fiber white-light interference and the structure of mechanical balance,an optical fiber balance is designed in this paper.Experiments show that the measurement accuracy of the balance can be greatly improved by observing the zero-order fringes of white-light interference instead of recognizing the balance pointer with the naked eye.When the length of optical fiber balance arm is 65mm,the tilt resolution angle of the optical fiber balance is=7.7×10^-55 rad,which is far higher than the human eye Angle resolution limit under the ideal state U=3.3×10^-4rad.The maximum weight deviation of the optical fiber balance in the range of 0～200g is less than 0.005g,the resolution is on the order of 10^-3g,and the measurement accuracy can be improved by optimizing the optical path scanning system and increasing the length of the optical fiber balance arm.