I skimmed the first article and can see your points. Not sure what is "opt"-coupling; I could understand "opto"-coupling much better. Furthermore, wavelength tuning... I have a hard time that just the red LED will produce enough to stimulate a solar cell to any major degree as stated.?
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The article also starts out early on with the statement, "However no practical devices were developed in their works." One could probably see why; this is like a cold-fusion paper.
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DerekK
DDK-ICS
Derek Koonce