We propose a simple all-fiber solution for coherent beam combining of Er-doped fiber amplifiers. This method, which we believe to be a new method, employs the effect of refractive index changes in Yb-doped fibers induced at by optical pumping at , which is performed for an active phase control in the fiber configuration. An algorithm based on population inversion in a two-level system supports the straightforward implementation of the effect into a feedback loop. Combining two 500 mW Er-doped amplifiers in a single-mode fiber is successfully demonstrated with control by laser diode. The method is shown to operate against the acoustic phase noise within the range of and with a rate of that potentially serves combining of at least 50 amplifiers similar to those used in practical work.
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