Thank you very much Sam Sung for the useful links. However, I think we have somehow deviated from the main problem Gurpreet stated. I think it would help him and me much more than a hundred links if you would very kindly make an osd file, demonstrating how to get multiple wavelengths from the same laser. Because you have read the papers you have introduced and sure know how to do that more than we do. I also have Gurpreet’s problem and it would be a real help if you do this for us. Thank you in advance.