The Research On Optical Fiber Laser For Measuring And Applications

Today, optical fiber has been widely used as the most important transmission medium in the telecommunication networks. Various optical fiber devices have been developed, which greatly enhance the flexibility of the network. Compared with other lasers, optical fiber laser has unparalleled advantages for its excellent performances and cheap prices. It has been widely applied in optical fiber communication, military, medicine , industry fabrication , optical fiber sensing and so on. To ensure single-frequency operation such lasers must necessarily be short or incorporate additional coupled cavities. One is a unidirectional loop laser, the other is the DFB laser. The main advantage of the DFB laser is the use of just one grating for feedback and wavelength selection, which provides better frequency stability. Using the broad-band light source with lower output power as the light source,the reflected light intensity is very weak and signal-to-noise ratio is low. So it is limited to a certian extent in the actual applications.The optic fiber laser is a high-quality light source with high signal-to-noise ratio. Having excellent performance such as good beam of light, narrow breadwidth and high power and so on, the optic fiber laser is applicable to sensing. Applying fiber sensor based on the optic fiber laser can make up the shortage that laser FBG sensor has. Using the optic fiber laser type's sensor can measure the physics parameter such as the temperature, stress, strain, field intensity, current and otherwise. The research on optic fiber laser for measuring and applications will better the performance of fiber sensor , broaden the applications of optic fiber laser and fiber seneor's. In this paper, the research on optical fiber laser for measursing and applications, has been investigated theoretically and experimentally. The main contents are listed as follows.(1) Summarize the basic principles of optical fiber laser and its application in optical fiber sensing, providing foundation of designing optical fiber lasers in the following.(2) Output characteristics of Erbium-doped fiber laser have been investigated. The effects of the intra-cavity loss, the EDF length, the output coupling ratio, and pump power have been studied. A Er-doped fiber laser with high stable quality andnarrow bandwidth is realized.(3) The properties of stress for FBG sensor and a fiber sensor based on the DBR fiber laser have been studied experimentally. Experimental results show good linearity.The optic fiber laser sensor shows higher signal-to-noise ratio and output power.