Towards Ultimate High-Power Scaling: Coherent Beam Combining of Fiber Lasers
Round 1
Reviewer 1 Report
The review article “Towards ultimate high-power scaling: coherent beam combining of fiber lasers” by Hossein Fathi, Mikko Närhi, and Regina Gumenyuk is devoted to a very important and topical problem of power scaling of fiber laser systems based on coherent beam combining. High power fiber laser systems are demanded for a lot of applications but power increasing for one channel is limited by different factors such as stimulated Brillouin scattering, stimulated Raman scattering, self-phase modulation, self-focusing, four-wave mixing, transverse mode instability, and pumping limitations. These issues are discussed in the Introduction as well as main ways of their overcoming. Section 2 summaries the published results concerning incoherent beam combining. Section 3 is about the main principles of coherent beam combining. Section 4 and 5 are devoted to coherent beam combining of ultrafast fiber lasers and CW fiber lasers, respectively. Section 6 contains conclusions.
The authors performed an excellent work. The main achievements in the field of beam combining are classified and summarized. The corresponding diagram in Figure 1 demonstrating different approaches to beam combining is very informative and useful. Tables 1-3, which compare the results of different groups, are very valuable to readers. There are more than 300 relevant references in the manuscript reflecting state-of-the-art. The most striking and outstanding results are reported in more detail. The manuscript is well written, well organized, and well illustrated.
I cannot find weakness of the manuscript and have no suggestions to the authors on how to improve their work (only typos in lines 2 and 1245: combing->combining).
So, I am happy to recommend this manuscript for publication.
Author Response
Dear reviewer,
I am much obliged for your kind review and comments. The mentioned typos are corrected in the manuscript, which are highlighted in the text.
The corrected manuscript is attached.
Best regards,
Hossein Fathi
Author Response File: 
Author Response.docx
Reviewer 2 Report
This manuscript review the solutions to high-power scaling of fiber laser. The structure of the article is well organized. It is easy to read although it is very long and covering so many topics. The only confusing thing is in the Figure 1(Topic map of the laser beam combining). In the tree on the right (CBC), there are Tiled aperture, Mixed aperture, and Filled aperture in the branch of Active. while at the sub-branch of Filled aperture, there are Tiled aperture and Filled aperture in CW lasers branch. After clarification this confusion, I think it can be published.
Author Response
Dear reviewer,
I am much obliged for your meticulous review. There was a mistake in Figure 1, which is corrected and replaced in the manuscript. Moreover, two typos in lines 2 and 1244 were corrected which are highlighted in the text.
The corrected manuscript is attached.
Sincerely yours,
Hossein Fathi
Author Response File: Author Response.docx
Reviewer 3 Report
The paper is excellent either for presentation and contents
This referee recommends the relevant publicatyio
Author Response
Dear reviewer,
I am much obliged for your review.
We have included over 300 references and believe covered as many as possible relevant publications in this review.
Sincerely yours,
Hossein Fathi
