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From: wiml@milton.u.washington.edu (William Lewis)
Newsgroups: sci.electronics,sci.physics
Subject: Re: Lasers for communication
Message-ID: <7504@milton.u.washington.edu>
Date: 13 Sep 90 21:17:26 GMT
References: <1872@oucsace.cs.OHIOU.EDU> <153DAVE@ORION> <1990Sep13.020325.10622@nmt.edu>
Organization: University of Washington, Seattle
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In article <1990Sep13.020325.10622@nmt.edu> pahsnsr@nmt.edu (Paul A. Houle) writes:
>                                       ...  Controlling power input to the
>laser is also possible,  but tends to add more noise and,  for most models,
>you'll have to considerably modify the power supply.  A final trick is to
>use a bit of mirror that you can vibrate to move the beam on and off the
>detector.

    I have a HeNe laser that I'd like to use for communication also. 
The tube itself has no provision for modulation, but the power supply
is seperate (built from a kit) so modifying it would be no problem.
My question is: how would I go about adding a modulator to the supply?
Do I just have to modulate the current? Does anyone have an example
schematic? I'm not well versed in high voltage electronics (high
voltage to me means "more than TTL levels" =8) ) 


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