Passive phase locking of an array of four fiber amplifiers by an all-optical feedback loop
ABSTRACT We report the passive phase locking of an array of four fiber amplifiers in a unidirectional ring cavity. The feedback loop consists of a single-mode fiber that filters intracavity the far-field pattern of the four emitted beams. The pointing of the laser output can be managed by the intracavity filtering.
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ABSTRACT: In this manuscript, we theoretically and experimentally investigate the influence of mode mismatch errors on active coherent polarization beam combining (CPBC) system. Firstly, by incorporating a piezo-mounted mirror (PMM) to generate artificial tilt phase aberrations, we design an experimental system to theoretically and experimentally investigate the influence of mode-mismatch errors induced by tilt phase aberrations on the combining efficiency of CPBC system. Further, by employing a spatial light modulator (SLM) to impose higher-order phase aberrations, the impact of mode-mismatch errors induced by higher-order phase aberrations on the CPBC system is also studied specifically. In the situation of adding each man-made aberration, experimental results correspond well with the theoretical ones. By theoretical and experimental analysis, we also show that the combining efficiency of the CPBC system is susceptible to the phase mismatch errors among different channels while has high tolerance on the intensity mismatch errors, which is compatible with the analysis in other CBC configurations. Besides, experimental results also show that the combining efficiency of the CPBC system is independent on the modulation frequency of dynamical tilt phase aberrations. Our analysis and designs provide useful approaches to diagnose the influence of mode-mismatch errors on CPBC system and optimize the whole CPBC system specifically.Optics Express 11/2014; 22(22). DOI:10.1364/OE.22.027321 · 3.53 Impact Factor
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ABSTRACT: We demonstrated a passive phase locking of a seven-element 352 W all-fiber polarization-maintaining amplifiers array using an all-optical feedback loop. Every single channel has four-stage amplifiers and is seeded by a broadband master oscillator for stimulated Brillouin scattering free. The seven laser beams are tiled side by side into a hexagonal laser array with a high space duty ratio of 65% in the near field. When system is in closed-loop, a visibility more than 90% of coherent pattern in the far field is obtained. By using the all-optical feedback loop and more pump power, higher power scaling with high beam quality appears to be achievable in a coherent beam combination system.Photonics Asia; 11/2012
Conference Paper: Coherent Laser Combination using a Self-Fourier Cavity[Show abstract] [Hide abstract]
ABSTRACT: A coherent fiber laser array in a Self-Fourier cavity is described. The Self-Fourier cavity has been shown to coherently combine an array of fiber lasers through its ideal supermode discrimination as a result of its passive coupling matrix of rank 1. Recently, a static model has been developed that extrapolates this technique to an array of very large number of fiber lasers by exploiting the gain-dependent phase shift and incorporating specific levels of individual feedback to each fiber amplifiers, transforming them into regenerative amplifiers. By engineering the resonator in the manner described here, this enables us to circumvent predicted scaling limits and offers the possibility to achieve a highly phased state for a large number of fiber lasers in such an array. Experimental results are presented, the model of operation is discussed, and scaling predictions are presented.Laser Optics 2010; 07/2010