Coherent beam combining of a large number of PM fibers in a 2D fiberarray

Yu, Charles; Kansky, Jan; Shaw, S. E. J.; Murphy, Daniel V.; Higgs, C. Fred

doi:10.1109/cleo.2006.4627929

Cited by 6 publications

(6 citation statements)

References 4 publications

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“…CBC has been implemented for various types of lasers, such as diode lasers [10][11][12], solid state lasers [1,13,14], fiber lasers [15][16][17] and gas lasers [18], to improve the brightness and beam quality of the combined beam. Due to the advantages of fiber lasers and beam combining requirements, they are the most applicable choice for beam combining systems.…”

Section: Coherent Beam Combiningmentioning

confidence: 99%

Step bulk arrangement of 19 fiber laser collimators for directed energy applications

Ghasemi¹,

Haghparast²

2021

Laser Phys.

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We designed an arrangement of 19 high-power fiber laser collimators on an aluminum step bulk in coherent combination for use in directed energy applications. Strong environmental turbulence degrades coherent beam combining advantages; therefore, we only consider low-turbulence levels. The combining elements are single mode 3 kW high-power fiber lasers, which are collected by 19 right-angle prisms in two concentric hexagonal rings for combination. With this configuration, a high combining efficiency of 88%, a high filling factor up to f = 0.9 and lower cost production of the beam combining process are possible.

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Section: Coherent Beam Combiningmentioning

confidence: 99%

Step bulk arrangement of 19 fiber laser collimators for directed energy applications

Ghasemi¹,

Haghparast²

2021

Laser Phys.

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“…An interferometric technique, based on the analysis of an interference pattern of the output beams recorded on a camera, performs a collective phase measurement of the beams from a single image [15]. This method is *marie.antier@thalesgroup.com therefore a promising candidate towards very large channel counts applications.…”

Section: Introductionmentioning

confidence: 99%

Interferometric phase measurement techniques for coherent beam combining

et al. 2015

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Coherent beam combining of fiber amplifiers provides an attractive mean of reaching high power laser. In an interferometric phase measurement the beams issued for each fiber combined are imaged onto a sensor and interfere with a reference plane wave. This registration of interference patterns on a camera allows the measurement of the exact phase error of each fiber beam in a single shot. Therefore, this method is a promising candidate toward very large number of combined fibers. Based on this technique, several architectures can be proposed to coherently combine a high number of fibers. The first one based on digital holography transfers directly the image of the camera to spatial light modulator (SLM). The generated hologram is used to compensate the phase errors induced by the amplifiers. This architecture has therefore a collective phase measurement and correction. Unlike previous digital holography technique, the probe beams measuring the phase errors between the fibers are co-propagating with the phase-locked signal beams. This architecture is compatible with the use of multi-stage isolated amplifying fibers. In that case, only 20 pixels per fiber on the SLM are needed to obtain a residual phase shift error below λ/10rms. The second proposed architecture calculates the correction applied to each fiber channel by tracking the relative position of the interference finges. In this case, a phase modulator is placed on each channel. In that configuration, only 8 pixels per fiber on the camera is required for a stable close loop operation with a residual phase error of λ/20rms, which demonstrates the scalability of this concept.

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“…24mm and the spacing between two adjacent microlens is 0. 25mm, which results in a duty cycle of approximately 96% [15]. In the coherent beam combination of fiber lasers, the output end of fiber is required to have high positioning accuracy.…”

Section: Introductionmentioning

confidence: 99%

A novel fiber collimator with the rod lens for coherent beam combination of fiber laser array

Luo

et al. 2023

AOPC 2022: Advanced Laser Technology and Applications

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Coherent beam combination of fiber lasers is considered to be a promising technology to obtain high-brightness laser. In tiled-aperture coherent beam combination, in order to obtain the best combination effect, a high fill factor is required for the beam array output from the fiber collimators. Thus, the collimator array must be closely arranged and each single-mode Gaussian beam must be truncated, which brings great difficulties to design a fiber collimator. We propose a scheme of fiber collimator based on rod lens, which compares to the fiber collimator with the thin lens, has the following advantages. Firstly, rod lenses for beam collimation can be arranged in an array without a frame to get a high fill factor of fiber collimators. Secondly, the single-mode Gaussian beam from fiber can be truncated in any proportion to get a good result of coherent beam combination. Thirdly, almost all of the laser energy output from a fiber include the stray light with the large NA is emitted into space outside the collimator by the rod lens. Fourth, the structure of fiber collimator with the rod lens is simple, which makes it easy to build a large number of fiber lasers array. In this paper, we have developed a rod lens colllimator and carried out the preliminary experiments, the results show that the rod lens collimator can emit a collimated beam with the good beam quality, and all stray light with the large NA in the collimator can be exported to space.

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Coherent beam combining of a large number of PM fibers in a 2D fiberarray

Cited by 6 publications

References 4 publications

Step bulk arrangement of 19 fiber laser collimators for directed energy applications

Step bulk arrangement of 19 fiber laser collimators for directed energy applications

Interferometric phase measurement techniques for coherent beam combining

A novel fiber collimator with the rod lens for coherent beam combination of fiber laser array

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