Talk:Optical amplification
Reviewer A :
That's fine for me. Let's do as you say and let yet to come contributors decide of this article's future.
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Reply to Reviewer A
My first point is that, although this article is actually a very nice introduction to the subject, obviously intended for readers of different levels, it lacks somehow the generality that the entry of an encyclopedia would require. Yes, the matter of what encyclopedia entries may look like, is debatable. I went through the Scholarpedia contents, and I found that some papers are forthright impossible to grasp from line #1. Most of the contributors assume that the reader made his/her PhD in their subject. Although I took care to remain accessible and self-contained in my presentation, I do not feel guilty if the level is a bit higher than that the “ideal” encyclopedia or of expectations. For certain, it is higher and far more involved/detailed than “Wikipedia” articles on the subject, and that concept was my initial drive to accept the invitation. If a key specialist (I am not alone, here !) offers a public lecture on his subject, better the lecture be good and have some thrust. People who want to know about lasers and amplifiers have plenty of textbooks and tutorials. Besides, I understand that the paper could be incrementally improved by future additions, which, if recognized worth, and with the consent of the initial author, would enable these contributors to become co-authors. This idea sounded very fine and innovative to me, and this is why some aspects of the subject were purposefully left behind. My main concern is that even if the parametric amplification has not found so far much application, it should not be ignored in an article about optical amplification meant for researchers and scholars. This is always the issue with any attempts to lecture about Optical Amplification. As everyone is aware, laser and (non-degenerate) parametric amplification, in which we may place Raman and Brillouin (with phonons as idlers), share some physics (e.g. 3dB noise limits, higher for SBS), despite wholly different physical processes. With parametric amplifiers in the general case, the difficulty is that the global theory must start from quite different first-principles. The classical treatment requires the understanding of 2nd and 3rd-order NL susceptibilities, including tensor properties, space and 1D configurations, etc. In that view, SHG is optical amplification (as we know, it even works in optical glass fibres, which were supposed to be nonlinear only to the 3rd-order). All this takes us a bit too far, for a general subject that, in my academic view, “must” be introduced from the laser and A.E. stimulated emission. After this, the brave may explore the OPA world, with classical and quantum tools. The reverse wouldn’t make sense, neither work out. Another consideration is that the field of OPAs has immensely progressed since, in particular in noiseless (or sub-3dB noise regimes), and clever pumping schemes, thinking about P.Andrekson et al. work, and others. I feel that these people may be far more relevant than me to produce a Scholarpedia entry on OPA. Another point is that in an encyclopedic article, "we" should just never be used. Compared to other articles already published, the list of references is too short, and composed essentially of references to the author's work. Even if the contribution of Emmanuel Desurvire to the domain is remarkable, this article is a little bit too centered on the author's work. A sentence as "a discovery first reported in Desurvire 1999" is not welcome for instance. You have a fine point with this. The “we” to guide/associate the reader (as in “as we have seen”) is not in question here. The “we”, as pointing to personal work, may indeed sound inappropriate indeed, and can be easily turned otherwise. I must however disagree about the issue of the references list. Saleh & Teich is probably the best-ever reference book on lasers/amplifiers, if we overlook the most precious Yariv, Siegmann and Milonni-Eberli ones. But these are about “lasers”, and hardly treat “amplifiers” ; my two reference books, including the second, which is co-authored, are about EDFAs and first-principles thereof. The point is not to cite other minor/introductory books to make the reference list artificially look complete or fair. When an author cites his own textbook, or textbooks from others, this does not suggest in any way that either one has “invented“ the field ! It just shows a recommended selection, hopefully the best adequate for student/teacher reference.. Now about “papers”, the Shimoda et al. and the Yamamoto/Mukai are “musts”. I completed the list with two of my own papers that hardly received the highest citations in my own publication cursus. Yet, they are both relevant here. The second one (3D QBS) has been severely un-noticed in both the academic and industrial communities. The latter could not understand or care more about it. The former thought that it was obvious and well-known, without ever being able to bring a proof. Yet it was a “discovery” that laser OAs need two orthogonal vacuum-noise couplings to explain the noise sources, with a fully quantum treatment (as associated with the stimulated-emission process, and having nothing to do with square-law detection, a semi-classical treatment..). Specialists would argue that (our regretted) Herman Haus has published something similar in his last book.. But this was years after my communication, and we have exchanged a good correspondence about the subject of “conceptual anteriority”, which I preciously keep in my archives. It may thus appear at quick sight that my reference list is immaturely focusing on my own contributions. This is untrue: the reference books are there, and that paper on the 3D QBS is brought to the academic attention. I could have indulged in many other ways, by extensively citing my own work, but completely departing from the scope of the encyclopedia and subject matter, and here you would have a real point of worry and discontent. By the way, my reference list and text does not suggest anywhere that I am a co-inventor of the EDFA, for whatever this notion would mean here. A solution to many concerns could be a change in the title to make it more specific: "Principle of optical amplifiers" or something like that. But not a title as general as optical amplification if it should be limited to a peculiar type of amplification. As you stated yourself, OPAs have not proven their benefits yet (but they will) – I forgot SHG in the laser-source industry (and laser pointers); but let just consider how much the LAser has revolutionized society, and for that matter, the fibre LASER amplifier (EDFA), for the telecoms and the global internet. In my view, it doesn’t hurt that “Optical amplification” overlooks an introduction to OPA, since the applications do not compare. This being said, it is important not to induce the reader into the conclusion that OPAs do not exist! The last sentence of the first paragraph was probably insufficient. I have amended the text accordingly. Changing the title into “Optical laser amplification” would miss the point. The invention/discovery of “light amplifiers” definitely remains the LASER. Beside the fact that SRS, SBS, and ND OPA can be treated the same way, with the same conclusions. It should not make any problem, or phase anyone, considering the hypertext facilities in this publication medium, to include (in the near future) a link to a great “Optical Parametric Amplification” article. The english should be checked, too. I'm not a native (that is probably obvious), and that may explain why some expressions seemed a little bit strange to me - like "upon traversing said medium". The english should be as simple as possible, so that the article can be easily understood by anybody. For small things, maybe I could have made some modifications myself. The expression “upon traversing said medium” is in fact fully correct. I agree that it may sound a bit patent-attorney jargon stuff. But it reads well in the context, though. Please provide other examples that may sound really quite odd or obscure. About simplifying the English, I really don’t know how to effect any style changes. There is no way to change “a cat is a cat” into something more accurate or possibly inspiring. My writing is based upon a long practice with Wiley, and recently, Cambridge, with their tough copy-editing. However imperfect and/or perfectible, I don’t see any way such a text can be rewritten. After this people might say that I did not explain clearly enough the meaning of “i” or “a^+” in the equations. I believe that Scholarpedia should not be restricted to “natives”, based upon the fact that English is the common language. Finally, in teaching exact sciences, the competition for excellence is not about language : if one is accurate and clear, one may win any class worldwide, that they will be happy people To conclude on a less negative comment (sorry for that, reviewers are not here to make only compliments), I think the approach chosen by the author is quite refreshing - it should make the article easy to understand and use even by students, which is definitely not the case of other articles I've read. That's maybe what could explain the lack of generality of the entry as is now too. Your comments were relevant, truly meaning it. I hope I have responded accurately and in a fair mode. We seem to rather strongly agree that clarity and thrust is not commonplace in the articles already posted (not talking about cosmology ones !!!) Every contributor, -- to recall : working for free and volunteering for a project that will not impact their careers, should remain free to keep their imperfections and own style, as long as “quality” is there, and shows. IMHO, as the dopy acronym goes, this is what the Scholarpedia students expect first and foremost. They don’t mind anything else. On that note, I shall come back to a previous observation : a key differentiator of this project is not to have a “wiki” paper entering into one’s ISI database (and boost one’s H factor), but, to have other people coming up with improvements/developments of the initial paper, becoming potentially co-authors of a historical endeavor. How easy the process, we don’t know as yet. But I already proposed to our editor that, for instance, the Laser paper from Townes be developed. Co-authoring with Townes! Such is the excellent challenge of this project, behind the project as of its current infancy. Here are some small remarks: After equation 1, there is an unfinished sentence. Corrected Fig 4 has too low a resolution. Most of the other ones, too. It is not intentional. The PPTs changed into JPEGs do not generally work too well for graphics. As benevolent contributors, we can’t spend so much time to refine graphics quality and meet any standards, which would imply otherwise to invest in re-drawing figures from old talks or publications. There is also an indirect advantage in the situation: people may not “steal” the pictures for their own unauthorized reproductions and publications. Why working a whole day to have people copy-paste the figures in their courses or books? It sounds fair that honest scholars may contact the author and ask him/she for a gracious PPT original, should it still exist or be found.
My first point is that, although this article is actually a very nice introduction to the subject, obviously intended for readers of different levels, it lacks somehow the generality that the entry of an encyclopedia would require. My main concern is that even if the parametric amplification has not found so far much application, it should not be ignored in an article about optical amplification meant for researchers and scholars.
Another point is that in an encyclopedic article, "we" should just never be used. Compared to other articles already published, the list of references is too short, and composed essentially of references to the author's work. Even if the contribution of Emmanuel Desurvire to the domain is remarkable, this article is a little bit too centered on the author's work. A sentence as "a discovery first reported in Desurvire 1999" is not welcome for instance.
A solution to many concerns could be a change in the title to make it more specific : "Principle of optical amplifiers" or something like that. But not a title as general as optical amplification if it should be limited to a peculiar type of amplification.
The english should be checked, too. I'm not a native (that is probably obvious), and that may explain why some expressions seemed a little bit strange to me - like "upon traversing said medium". The english should be as simple as possible, so that the article can be easily understood by anybody. For small things, maybe I could have made some modifications myself.
To conclude on a less negative comment (sorry for that, reviewers are not here to make only compliments), I think the approach chosen by the author is quite refreshing - it should make the article easy to understand and use even by students, which is definitely not the case of other articles I've read. That's maybe what could explain the lack of generality of the entry as is now too.
Here are some small remarks :
-After equation 1, there is an unfinished sentence. -Fig 4 has too low a resolution.
