 
Summary: VOLUME 80, NUMBER 14 P H Y S I C A L R E V I E W L E T T E R S 6 APRIL 1998
Synchronizing HighDimensional Chaotic Optical Ring Dynamics
Henry D. I. Abarbanel* and Matthew B. Kennel
Institute for Nonlinear Science, University of California, San Diego, La Jolla, California 920930402
(Received 18 September 1997)
We study chaotic ring laser systems as possible elements in a communications system. To be
useful it must be possible to synchronize the transmitter and receiver lasers. We show that chaotic
ring lasers can be synchronized using direct light injection from one laser into the optical cavity of
the second. This synchronization occurs even when both lasers are quite high dimensional and each
possesses many positive Lyapunov exponents. When the lasers are synchronized, the transmitted light
can be modulated with information bearing signals and the message accurately recovered at the receiver.
[S00319007(98)057159]
PACS numbers: 89.70.+c, 05.45.+b, 42.55.f
The use of erbium doped ring lasers in communications
devices [1] led us to inquire whether such lasers could
serve as the basis for optical communications while op
erating in a chaotic regime. Our work focuses on a sim
plified prototype of the actual erbium ring laser. The
delay differential equations of our model arise by integrat
ing the partial differential equations for the electric field
