High power fiber lasers are currently a hot research topic. Conventional studies on the fiber lasers have mainly focused on the scalar fieldoperation of the lasers, for the lack of simplicity. However, light propagation in a real high power fiber laser cavity could also involve in thenonlinear coupling between the two orthogonal polarization components of the light, which could result in a number of interestingfeatures. In the project we have both experimentally and numerically investigated the operation of fiber lasers where the vector nature ofthe light propagation in the laser cavity has to be considered. We have called such a fiber laser as the vector cavity fiber laser.Experimental studies on the operation of the fiber lasers have revealed a great number of interesting phenomena, such as the phase or thegroup velocity locked vector solitons, induced solitons, bright-dark pulse pairs, induced dark solitons in the anomalous dispersion cavity fiberlasers etc. Numerical simulations have also well confirmed the experimental observations and shown that the formation of the observedphenomena could be well explained by the nonlinear coupling between the two orthogonal polarization components of the light in thevector fiber cavity. Other effects have also been observed and theoretically studied.