Highly-Stablized Coherent Beam Combining Of Short-Pulsed Fiber Laser Using Active Feedback Control Loop

We demonstrate a short pulsed Yb-doped fiber laser system comprising two coherently combined fibers with 15ps pulse width and 20MHz repetition rate. The system delivers an average laser power of 6.6mW, of which the RMS error is only 0.13%. The stability is optimal for a coherent beam combining system with multiple combining stages, thanks to an active feedback control loop implemented in the system. The feedback control loop constantly checks the system output power, automatically maximizing and stabilizing it. Implementation of the active feedback control loop is simple, robust, and versatile.