In a message dated 97-01-11 08:08:36 EST, you write:

>The primary advantage of laser gyros over mechanical gyros is that
>lasers don't drift over time... This makes them suitable for use in
>aircraft, etc.

I do not know much about mechanical (or laser) gyros but lasers DO drift with
time, temperature and most other environmental conditions.  To what
degree?.....relative to the application.  A small drift for one application
might be massive for another.  Lasers drift not only in output power
amplitude.  They also drift in wavelength.  Semiconductor lasers (laser
diodes) also drift in their threshold current level, divergence, astigmatism
and even their polarization ratio.  I spent much time investigating these
things for a previous employer whose application was sensitive to all these.
 Many applications of laser diodes are digital with a wide margin between 0
and 1 with respect to these conditions so it is possible to ignore most
effects caused by environment.

Mark A. Corio
Rochester MicroSystems, Inc.
200 Buell Road, Suite 9
Rochester, NY  14624
Tel:  (716) 328-5850 --- Fax:  (716) 328-1144
http://www.frontiernet.net/~rmi/

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