Review of 1.55 μm Waveband Integrated External Cavity Tunable Diode Lasers

Round 1

Reviewer 1 Report

In the manuscript ' Research on 1.55 μm waveband integrated external cavity tunable diode lasers, ' the authors Zhang et al reviewed the current technique development of the integrated external cavity tunable diode laser in 1.55 μm range. This manuscript generally provided the reference for the readers on the relative topic thus can be suggested to be accepted as the publication of Photonics while some improvement must be done.

1. The title of the manuscript is kind of confusing as this is a review not a research report. The authors are suggested to add ' Review' to the title.

2. The authors are encouraged to add the application examples to the tunable diode lasers such as the optical coherence tomography.(G. Zhang, and W. Wei, “4-D Imaging of Beating Tissues Using Optical Coherence Tomography. ”IEEE Photon. J, 13, 3900211 (2021).)   

3. As the beam quality is also a key problem in diode lasers during applications, the authors are encouraged to do some discussions on the improvement of the beam quality of the tunable diode lasers. Especially, there is a GRIN fiber which is very promising in achieving the TEM00 beam which is very important in solid-state lasers.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript contains a review of recent research on integrated tunable diode lasers with emphasis on 1.55 um waveband. The topic seems to be quite specific and rarely discussed in such detail in the literature. So, I think that the paper would be helpful and interesting for specialists in laser physics and technics. Therefore, I can recommend acceptance with only a pair of minor comments:

1) The Introduction can be expanded by discussing the aims of this manuscript. Why have the authors decided to write it at all?

2) It should be "Mach–Zehnder interferometer", not "Mach–Zendel".

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The review article describes the progress of research on laser diodes with a wavelength of 1.55 µm and an external resonator. The content is well done - but some more detailed descriptions of the techniques would be helpful. However, there are many linguistic, grammatical and punctuation errors in the text. This makes a very sloppy impression, which also casts doubt on the accuracy of the content.  The first question I have, however, is why 14 authors are needed for a review article - 14 authors would be a lot in my eyes, even for a paper that deals with a new technology plus experimental proof of the parameters, and I would ask myself what each individual has contributed - I can understand this even less in a review. Especially when there are so many technical errors.
Some remarks:

Mach Zendel  = Mach-Zehnder ? -

What is Q (most readers will know, but not all),

in Fig.1 there is no GC, SSC PS... - these abbreviations should be explained in the text when they appear for the first time

Fig. 4 Transmi ?

There is no Table 6 - Table 6 should be table 2

Generally: there should be space beween number and unit, there should be space after a comma,

Author Response

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Author Response File: Author Response.pdf