Re: Current Controller for Laser Diode

From: Ken Smith (kensmith_at_green.rahul.net)
Date: 02/24/05 

Date: Thu, 24 Feb 2005 14:53:16 +0000 (UTC)

In article <421cb798$0$3404$5402220f@news.sunrise.ch>,
Rene Tschaggelar <none@none.net> wrote:
[...]
>Well, an aspherical lens, a few squaremillimeters of AR coat,
>a squarecentimeter of grating is doable for a couple of dollars,
>it is the mounting and handling that is time consuming.
>With some automation, in numbers, the price should come down.
>Yes, the mechanical stability is important. Possibly thermally
>stabilized. But a micro setup should be doable.

Its the fine machined parts that worry me the most about the costs. One
nice thing about the NIST project is that the fine machining is done with
normal silicon processing steps. The disadvantage is the same thing.
Mere mortals can't round up enough cash to buy the machines to make
millions of low cost atomic clocks.

>Ah, they are locking to maximum/minimum absorption with
>the 9GHz sidebands ? That is not that trivial. Nor
>immediately to be made small. With some custon microwave
>chips though...

They have overlooked a couple of things (on purpose perhaps) in their
presentation. The cell has to be warmed to about 60C and there has to be
a very good magnetic shield and "C coil" around it. In the proto-type the
cell is suspended inside another glass chamber using Kapton tape. None of
this is done with normal IC processing stuff. 

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