Development Of White-Light F-P Optical Fiber Sensor

The extrinsic Fabry-Perot (F-P) optical fiber sensor has many advantages, such as simple structure, low cost, high measure precision and broad measure range and so on. It could be easy to put into full production and have a lot of places to use. The white light interferometric F-P optical fiber sensor with broad spectrum light source solves the problem that the conventional optical fiber F-P sensor can only measures relatively, therefore this kind of sensor is considered as a delicate one with broad development that can be used in smart structure. The work of this paper is to develop a low reflectivity and tiny F-P cavity length extrinsic optical fiber F-P sensor according to the white light inferometric principle. (1)The optical fiber F-P cavity working principle and the effect of strain on optical fiber F-P cavity are analysised in detail using the inteferometric principle and white light interferometric principle. The mathematical model of extrinsic F-P optical fiber sensor is deduced. Based on these principle, the optical fiber F-P cavity length is calculated by the position of inteferometric wave crest, and then the impact of waste in optical fiber F-P cavity on the visibility of interferometric fringe is discussed and analysised. (2)The structural parameter of extrinsic optical fiber F-P cavity is particularly analysised and calculated in theory and then structural parameter of extrinsic F-P optical fiber cavity is offered. The reflectivity of surfaces in optical F-P cavity is ensured by theoretical calculation, and a 15μm length optical fiber F-P cavity is designed according to light source's trait. (3)The semiautomatic adjusting disk of optical fiber F-P cavity is designed, which is used to manufacture the tiny optical fiber F-P cavity, and every part of the desk is investigated at large. The manufactural technics of F-P optical fiber sensor head with the semiautomatic adjusting disk of optical fiber F-P cavity is illuminated at length, and whole manufactural process of sensor head is completed. For broadening the working range of sensor head, the design scheme of scaling the length of F-P optical fiber sensor by fusion splicer is offered. At the end, the places need improving in manufacturing the F-P optical fiber sensor are pointed out and the further research direction and steps are indicated.