Design And Manufacture Of Metallized Optical Fiber F-P Sensor And Its Temperature Sensing Characteristics

As the technical basis of modern information system,optical fiber sensing technology is now in the stage of vigorous development.As an important branch of optical fiber sensor,optical fiber Fabry Perot interference sensor is widely used in the measurement of strain,temperature,refractive index,humidity,acceleration,ultrasonic,displacement and other parameters.Optical fiber F-P sensor can be widely used in the sensing field because it has a series of advantages,such as simple structure,small size,high reliability,simple fabrication,and can transmit signals in a single optical fiber.Optical fiber F-P sensors can be divided into intrinsic Fabry Perot interference(IFPI)sensors,extrinsic Fabry Perot interference(EFPI)sensors and in-line Fabry Perot interference(ILFP)sensors according to the structure of sensing head.Many methods have been proposed for the fabrication of optical fiber F-P sensor,but there are still some defects.In this paper,the introduction of metal elements in the fabrication of optical fiber F-P sensor is proposed to produce optical fiber F-P sensor which can withstand higher temperature,and the temperature sensing characteristics are studied.The main research contents are as follows:1)Fabrication of optical fiber EFPI sensor based on in-situ plating method.In order to overcome the defects of using arc welding,organic adhesive bonding and laser welding to fix the optical fiber and capillary tube,an in-situ electroplating method was proposed to fix the optical fiber and capillary tube to make the optical fiber EFPI sensor,and the change of the reflection spectrum in the process of in-situ electroplating was monitored in real time.The conclusion is that the optical fiber F-P sensor based on in-situ plating method has smooth,compact and bright appearance,and the reflection spectrum is always complete and clear during the plating process.2)Research on temperature sensing characteristics of optical fiber EFPI sensor based on in-situ plating method.The temperature sensing experiment of EFPI sensor is carried out,and the results show that the reflection spectrum is clear and complete during the heating process,showing good temperature sensing characteristics.The temperature sensitivity of three EFPI sensors with different F-P cavity lengths reaches 700,600 and 400 pm/? respectively.3)The fabrication of fiber ILFP sensor based on fused quartz tube.The results show that the two ends of the fused F-P cavity are flat,and the fused quartz tube and fiber are not damaged.4)Metallization of optical fiber ILFP sensor based on fused silica tube.Electroless nickel combined with electroless nickel plating was used to metallize the optical fiber ILFP sensor.5)Research on temperature sensing characteristics of optical fiber ILFP sensor based on fused silica tube.The temperature sensing experiments were carried out on the optical fiber ILFP sensor before and after metallization,and the sensing results were compared between the two sensors after heating from room temperature to700?.The results show that the temperature sensitivity of the three optical fiber ILFP sensors with different F-P cavity length before metallization is 0.118 nm/??0.3475 nm/? and 0.6578 nm/?,and the temperature sensitivity of the metallized ILFP sensor is up to 0.323 nm/??0.915 nm/? and 1.5717 nm/?,which indicates that the temperature sensing characteristics of the metallized optical fiber ILFP sensor have been greatly improved,and the temperature sensitivity has been greatly improved.