A new type of combined phase conjugator consisting of a fused silicon rod and an optical fiber is realized in experiment. This conjugator combines a large diameter fused silicon rod with high laser damage threshold and a fiber with a low stimulated Brillouin scattering (SBS) threshold. The composed SBS oscillator-amplifier construction of the two cells type makes a forced SBS process, in which the Stokes beam reflected from fiber injects in the fused silicon rod. According to this mechanism the combined phase conjugating mirror possesses lower SBS threshold and higher reflectivity than the conjugator with bulk fused silicon, single optical fiber or combined fiber. It can also be used in a high power laser system. In a laser diode (LD) pumped high power high repetition rate master oscillator power amplifier (MOPA) laser system with the proposed conjugator, 42.05% reflectivity under 100 Hz was obtained with high beam quality. The beam quality parameter M2 was reduced from 3 to 1.6 and the beam spot was stable. Under 400 Hz repetition the beam quality parameter M2 reached 1.7.