Alcatel

François Boubal

Vincent Havard

Jean-Pierre Blondel

Eric Brandon

Patrice Le Roux

Laurent Labrunie

Laurence Buet

An optical transmission system uses as its transmission medium a fiber having chromatic dispersion. A sender emits an optical signal to be transmitted into the fiber. A sender emits into the transmission medium pumping light constituting a first pump adapted to pump the optical signal by the Raman effect and pumping light constituting a second pump adapted to pump the first pumping light by the Raman effect. The first pump and the second pump are amplitude modulated and the envelopes of the first pump and the second pump are decorrelated in time. This decorrelation limits the efficiency of the Raman pumping of the first light by the second light on emission. Varying the decorrelation in time between the pump envelopes varies the region of the transmission system in which the signals are amplified.

Fiber optic transmission system using Raman effect amplification

The invention refers to a safety procedure for optical fiber systems. Such systems are widely used in telecommunication to transport optical signals between a transmitter terminal and a receiver terminal. By the invented safety procedure the optical input power fed into said optical fiber system is automatically shut off or at least reduced in case of an unintended escape of light from at least one fiber. A safety interface, provided in the transmission line detects changes of the total optical output power in at least one fiber and initiates a shut-down of the input power as soon as a decrease of the total output power is detected, that exceeds a predefined value within a predefined time window. Thus the slope of the total output power is measured and evaluated rather than its absolute value.

Safety procedure for optical fiber systems and safety interface to carry out such safety procedure

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Viry Chatillon, France

François Boubal