A new way of achieving phase shifts in fiber Bragg grating (FBG) by increasing direct current refractive index of the FBG is proposed. Simulation and experimental results show that arbitrary phase shifts can be achieved by the presented method. Comparison between the proposed direct-current phase-shift and traditional discrete phase-shift FBG is made, which shows a good agreement. 7- and 63-chip optical code-division multiple-access en/decoders are fabricated. The fine en/decoding performance verifies the feasibility of fabricating multi-phase shifted FBG by the proposed method. High-precision and phase mask are not required in fabrication. This method has advantages in cost-effectiveness, flexibility and simplicity compared to traditional ways.