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From: rhorn@infinet.UUCP (Rob Horn)
Newsgroups: sci.physics,sci.electronics,sci.research
Subject: Re: Modulating laser beams.
Message-ID: <972@infinet.UUCP>
Date: Tue, 13-Oct-87 10:25:30 EDT
Article-I.D.: infinet.972
Posted: Tue Oct 13 10:25:30 1987
Date-Received: Thu, 15-Oct-87 22:18:33 EDT
References: <688@mplvax.nosc.MIL>
Reply-To: rhorn@infinet.UUCP (Rob Horn)
Organization: Infinet, Inc.  North Andover, MA
Lines: 26
Keywords: digital modulation, laser.
Summary: Coherent Optical Communications, DFB Lasers, Intro reference
Xref: mnetor sci.physics:2493 sci.electronics:1567 sci.research:269

In article <688@mplvax.nosc.MIL> david@mplvax.nosc.MIL (David Almagor) writes:
>I would like to hear from you "Laser experts" if anybody out there,
>commercially or scientifically is digitally modulating Laser beams, 
>with something more sophisticated than amplitude shift keying or 
>on-off keying. I basically refer to sorts of phase shift keying or 
>something similar.

Yes.  There is now moderate laboratory experience with coherent
optical communications (FSK, PSK, QPSK) and very limited field
experience.  These have tremendous potential for making bandwidth
available.  Rates like 20 Gigabits/sec have been demonstrated on a
single fiber.

For a decent overview of this and related technologies see ATT
Technical Journal, Jan/Feb 1987.  There was also a joint issue of IEEE
Special Areas of Communication and IEEE Optical Society on coherent
optical.  Finally, look in abstracting services for the keywords
coherent optical or distributed feedback lasers (DFB) for other
related articles.  I included the lasers because DFB is the dominant
modulated laser technology at the moment and this improves your hit
rate in finding abstracts.

-- 
				Rob  Horn
	UUCP:	...harvard!adelie!infinet!rhorn
	Snail:	Infinet,  40 High St., North Andover, MA
	(Note: harvard!infinet path is in maps but not working yet)