[sci.electronics] Modulating laser beams.

david@mplvax.nosc.MIL (David Almagor) (10/11/87)

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. Thanks for the patience, My knowledge in optics is
limited.

David.
-- 
David Almagor          | Phone 619-534-1813           | 
The Marine Physical lab| or:   619-442-3451 ext. 3173 | 
UCSD, San Diego,       |                              |david@mplvax.nosc.mil 
Ca 92152               |                              |

rhorn@infinet.UUCP (Rob Horn) (10/13/87)

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)