All-fiber 50 W coherently combined passive laser array

Abstract

We experimentally demonstrate 50 W of spontaneously phase-locked two-laser array in an all-fiber and all-passive configuration using large-mode-area (LMA) polarization-maintaining fiber laser cavities and an LMA fiber coupler. We show that both laser cavity length difference and fiber nonlinearity play an important role in achieving efficient and stable coherent beam combining. In addition, we compare the difference in coherent combining efficiency by using fibers with different mode-field diameters and discuss the underlying phase-locking mechanism and its power scalability.

Passive coherent beam combining of two femtosecond fiber chirped-pulse amplifiers

“…This necessitates the implementation of a phase detection scheme, feedback electronics, and the insertion of a phase-controlling element in each amplifying arm. Passive coherent combination techniques have been investigated, but in this case the recombination is done within an oscillator [7], which limits their potential. Ultimately, a setup that performs passive coherent beam combining of amplifiers could be a real benefit for obtaining higher peak-powers with FCPA.…”

Modal and scalability analysis of a zigzag array structure for passive coherent beam combining

“…In the CBC category, depending upon methods used to achieve the phase locking in an array, there are two subcategories, the first being active CBC (e.g., master oscillator power amplifiers (MOPA) [6][7][8][9][10]), and the second being passive CBC (e.g., evanescently coupled laser arrays and common cavities) [11][12][13][14][15][16]. Usually, in an active CBC system, the precise control of phase of each emitter in an array renders the system consuming of space, complex, and expensive.…”

Coherent Polarization Beam Combining of Four High-Power Fiber Amplifiers Using Single-Frequency Dithering Technique

“…Coherent beam combination (CBC) provides a feasible approach to overcome the limitations above-mentioned [3][4][5][6][7][8][9][10][11][12][13][14]. In the common CBC configuration, all the emitters are tiled into an array, which induces a portion of power encircled into the sidelobes in the far-field pattern [14], thus inevitably degrades the beam quality and power concentration [5][6][7][8][9][10][11][12][13][14]. As one of the CBC structure, coherent polarization beam combining (CPBC) overcome the deficiency of sidelobes due to that all the beams are coaxially combined [15,16].…”