We demonstrated a stable single-frequency, single-polarization operation of ytterbium-doped fiber laser. As a novel practical method to realize single-polarization operation of fiber distributed Bragg reflector (DBR) laser, we proposed self-injection locking (SIL) with an active fiber ring feedback cavity. The laser has high output power exceeding 15 mW, wavelength of 1053.20 nm, and side-mode suppression ratio greater than 60 dB. The SIL fiber laser shows the improvements in output power and side-mode suppression compared with the fiber DBR laser. No mode-hopping is observed within 2 hours.