OPTICAL TRANSMISSION SYSTEM WITH COHERENT OPTICAL TIME DOMAIN REFLECTOMETRY

摘要

The invention concerns a method for reducing interactions between the signal in the transmission direction (2) and the back scattered noise coming from the other transmission direction (1) in a link through non-bi-directional and amplified optical fibre, having an optical loop-back (18, 19, 21) of the amplifiers (13, 14; 15, 16) to enable COTDR (coherent optical time domain reflectometry). The method is characterised by a spectral broadening, for example by modulating the wavelength over at least one of the transmission directions. Said modulation is produced for example simply by modulating the injection current of a laser used as transmitter (3). A low frequency modulation - of the order of kHz - is suitable, thereby reducing interactions while enabling COTDR. The invention also concerns a link implementing the method.