[Microwave] An update to the best low noise signal sources.

[Dr. Gerald N. Johnson]

In the April 2009 Microwave Journal that arrived today there is an
advertisement from OEwaves (www.oeowaves.com, page 83). They claim a
phase noise of -145 dBc/Hz at 10 kHz offset at 10 GHz. That is really
good.

An article about it is referenced on their web page:

> Phase noise of a high performance OEO and an ultra low noise floor
> cross-correlation microwave photonic homodyne system 
>         Authors: Danny Eliyahu, David Seidel, Lute Maleki
>         
>         OEwaves, Inc., Pasadena, CA
>         
>         Proceedings of Frequency Control Symposium, 2008 IEEE
>         International, Honolulu, HI.
>         pp. 811-814, 19-21 May 2008. ISBN: 978-1-4244-1794-0 DOI:
>         10.1109FREQ.2008.4673111
>         
>         Abstract
>         This paper describes two recent types of opto-electronic
>         oscillators. The first is a long fiber opto-electronic
>         oscillator, utilizing a high power laser with long delay, and
>         consisting of low noise components. This oscillator generates
>         a stable 10 GHz signal with phase noise of -163 dBc/Hz at 6
>         kHz offset from the carrier. The second is a low noise 10 GHz
>         compact opto-electronic oscillator. This latter oscillator
>         consists of coupled optical and microwave loops utilizing a
>         short fiber. We also report on an automatic ulta-low noise
>         floor measurement system, designed and built to measure the
>         phase noise of the above (and other) oscillators. This delay
>         line cross-correlation measurement system utilizes microwave-
>         photonic links, eliminating the need for a second oscillator.
>         This system provides quick and reliable measurement of the
>         oscillator under test.    Read More
>         
Might be a viable technique we could be using. Might only be affordable
with a DARPA grant. I've not yet read more.

Beginning on pages 106 - 112 is a product feature from Pascall
Electronics Ltd (www.pascall.co.uk), talking about a 100 MHz range OCXO
(their F series) with a guaranteed phase noise better than -178 dBc/Hz
at 10 kHz offset at 100 MHz. Temperature stability better than 2 x 10^-7
over a temperature range of -30 to +70 degrees C. Ultimate phase noise
down to about -190 dBc/Hz at around 10 MHz offset. That is a QUIET
oscillator. http://www.mwjournal.com/Journal/article.asp?HH_ID=AR_7320
It will take a free registration to read the entire article.

73, Jerry, K0CQ