US Patent 7079733 Optical communication system, optical communication apparatus, and optical cable

An optical communication apparatus is connected to the other communication apparatus by an optical fiber. The optical fiber cable comprises conducting wires. By interconnecting an output-side conducting circuit provided to the optical communication apparatus and an input-side conducting circuit provided to the other communication apparatus, a detection circuit is constituted. The optical communication apparatus comprises a monitor for monitoring a state of conduction of the detection circuit and an output control portion for controlling a laser diode. When the optical fiber cable is extracted from the optical communication apparatus, it is extracted from the other communication apparatus, and it is broken, the output-side and input-side conducting circuits are cut off. The monitor monitors a change in the state of conduction. If the monitor detects a change in the state of conduction, the output control portion stops emission of light from the laser diode.