Interestingly they use regenerative dividers. Pretty good read. Thanks Paul WB8TSL
On Tue, Jan 13, 2015 at 4:49 PM, Tom Knox <act...@hotmail.com> wrote: > I think the key to this concept is an optical comb filter. > Archita Hati of the Phase Noise measurement Group at NIST has been > researching ultra low phase noise 5MHz references using an optical > standard and comb filter > as well as extensive RF components to down converting to the desired > frequency. > In experiments I believe she has achieved phase noise better then -154db @ > 1Hz offset. > It does appear to be the future but currently is far to large and complex > for most if any > practical use. I believe this link is the paper by Archita Hati I referred > addressing > State-of-the-Art RF Signal Generation From Optical Frequency Division. > http://tf.boulder.nist.gov/general/pdf/2646.pdf > Enjoy; > Thomas Knox > > Thomas Knox > > > > > From: namic...@gmail.com > > Date: Wed, 14 Jan 2015 07:00:09 +1100 > > To: time-nuts@febo.com > > CC: namic...@gmail.com > > Subject: Re: [time-nuts] Current state of optical clocks and the > definition of the second > > > > > > THe stability /accuracy of lasers is entirely dependent on the cavity > length. > > Materials used are usually invar or silica, so you are no better off than > > with a quartz crystals. > > They are just a resonant cavity. > > cheers, > > Neville Michie > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.