  A chaos-based communication scheme allowing simultaneous bidirectional
message transmission (Opt. Lett. 32, 403, 2007) is investigated numerically.
Incoherent feedback and coupling case is analyzed, which is expected in real
long-distance optical communication systems. It is shown that identical
synchronization of chaotic laser waveforms and bidirectional message
transmission are possible as in the coherent coupling case. However, the
chaotic regime at incoherent feedback and coupling is quite different. It is
regular destabilized relaxation oscillations with the chaotic envelope. Such
dynamics leads to restriction of the transmitting signal bit rate by a portion
of relaxation oscillations frequency.
