The Investigation Of MOPA Single-frequency Fiber Laser At 1.0 ?m

In the past few years,single-frequency laser source at 1.0 ?m waveband has attracted a lot attention for its important application in different fields,such as,non-linear frequency conversion,gravitational wave detection,beam combining and optical frequency standard.By far,the main method to get the single-frequency laser at a central wavelength of 1.0 ?m waveband includes the traditional bulk solid lasers and fiber lasers.However,the volume of traditional bulk solid lasers is usually very huge and the structures are also complicated with many bulk optical components used in them.It is not convenient to test and maintain the traditional bulk solid lasers,and output from the traditional bulk solid lasers is sensitive to the surroundings.So they can not satisfy the applications in field which is usually surrounded by complex conditions.Compared with the traditional bulk solid lasers,fiber lasers at 1.0 ?m waveband can make up for the drawbacks and are compact,reliable,easy to test and maintain.What's more,their costs are lower,their craftsmanship is simpler,and their performances are better.In this dissertation a highly Yb3+-doped phosphate glass fiber developed by our research institute as the gain medium of 1.0 ?m single-frequency fiber laser is used and an amplifing system is made.Much attention is paid into the design,development process and the performances of them.The study includes:1.By optimizing the resonant cavity's length and the fiber bragg grating's reflectivity of the 1.0 ?m single-frequency fiber laser,with the help of the high gain Yb3+-doped phosphate glass fiber,a single-frequency fiber laser is made with a maximum output power of 34.8 m W at a center wavelength of 1033.81 nm and the power unstability is less than ±1%.A linearly polarized single-frequency fiber laser is made with a maximum output power of 46.5 m W at a center wavelength of 1064.41 nm,the power unstability is less than ±1%,and the polarization extinction ratio(PER)is lager than 24 d B.The laser's spectrum,single longitude mode,relative intensity noise(RIN)and linewidth are also studied.2.The successfully developed 1033 nm single-frequency fiber laser is usded as the seed source and self-developed Yb3+-doped phosphate glass fiber is used as the gain medium.A low noise 1033 nm Yb3+-doped phosphate glass fiber MOPA(master oscillator power amplifier)amplify system is made with the help of the SOA's(semiconductor optical amplifier)saturation absorption effect.An amplifying system uses the commercial available double clad Yb3+-doped silica fiber as the gain medium and consists of two amplifiers to have the 1064 nm linearly polarized single-frequency fiber laser amplified.The influence of the Yb3+-doped silica glass fiber's length in each amplifier of the amplifying system on the output power,the slope efficiency,and the signal noise ratio(SNR)of the fiber amplifier is studied and the optimum fiber length is got.What's more,the theoretical analysis and experimental study of stimulated Brillouin scattering(SBS)threshold are carried out on the fiber length and fiber core diameter.