Coherent beam combination of two fiber amplifiers with multi-dithering technique

Abstract

Coherent beam combination of two W-level fiber amplifiers with multi-dithering technique is demonstrated. In the experiment, the master laser is split into two channels. Multi-dithering technique is used for phase control. One channel is modulated with a 100 kHz sine wave produced by signal generator, and DSP lock-in amplifier is used for electric signal processing in the feedback loop. When the phase control loop is off, the far field interference pattern is blurred and dynamic with 20% fringe contrast. When the feedback loop is closed, the far field interference pattern is clear and stable with 72% fringe contrast, and 75% coherent combination efficiency is achieved.

Keywords

Fiber Laser / Reference Beam / MOPA / Fiber Amplifier / Heterodyne Detection

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