[time-nuts] Current state of optical clocks and the definition of the second
bruce.griffiths at xtra.co.nz
Wed Jan 14 01:21:57 EST 2015
Although the phase noise when using optical combs to generate Rf signals
is low there is no mention of the am noise.
On Tuesday, January 13, 2015 02:49:33 PM Tom Knox 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
> and comb filter as well as extensive RF components to down converting
> the desired frequency. In experiments I believe she has achieved phase
> noise better then -154db @ 1Hz offset. It does appear to be the future
> 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.
> Thomas Knox
> Thomas Knox
> > From: namichie at gmail.com
> > Date: Wed, 14 Jan 2015 07:00:09 +1100
> > To: time-nuts at febo.com
> > CC: namichie at 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
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