Abstract. An optical fibre communication line (OFCL) closed-circuited into a ring network is considered as a controlled automodulated oscillation source. Theoretical and experimental investigations of the amplitude and frequency of automodulation for stationary self-consistent automodulation and external synchronization regimes in such a system are given on the basis of a balance equations analysis. It is shown that this OFCL ring can be used as an optical fibre tester and sensor.
