Positionally independent application of an OTDR technique based on correlation in a branched optical fibre network during operation

Claim 1

A method of monitoring, by means of fault location with the aid of optical time-domain reflectometry based on correlation, at least a part of an optical fiber transmission network comprising at least one optical fibre connection for distributing an optical signal, modulated with a data signal, from a transmitter connected to the optical transmission network to at least one receiver, the method comprising the steps of: a first uncoupling step of uncoupling a first optical signal from the network at an uncoupling point in a fiber connection of the network ahead of said part of the network, said first optical signal being a fraction of the distributed optical signal; a second uncoupling step of uncoupling a second optical signal from the network at or near the uncoupling point, said second optical signal being at least a fraction of signals reflected in said part of the network being monitored; a converting step converting separately said first and second optical signals to first and second electrical signals, respectively, and a correlating step of correlating said second electrical signal with said first electrical signal.

Claim 2

A method of monitoring, by means of fault location with the aid of optical time-domain reflectometry based on correlation, at least a part of an optical fiber transmission network comprising at least one optical fibre connection for distributing an optical signal, modulated with a data signal, from a transmitter connected to the optical transmission network to at least one receiver, the method comprising the steps of: a first uncoupling step of uncoupling a first optical signal from the network at an uncoupling point in a fiber connection of the network ahead of said part of the network, said first optical signal being a fraction of the distributed optical signal; a second uncoupling step of uncoupling a second optical signal from the network at or near the uncoupling point, said second optical signal being at least a fraction of signals reflected in said part of the network being monitored; a converting step converting separately said first and second optical signals to first and second electrical signals, respectively, and a correlating step of correlating said second electrical signal with said first electrical signal.

Claim 6

A device for monitoring, by means of fault location with the aid of optical time-domain reflectometry based on correlation, at least a part of an optical transmission network comprising at least one optical fibre connection for distributing an optical signal, modulated with a data signal, from a transmitter connected to the optical transmission network to at least one receiver, the device comprising: a first uncoupling means for uncoupling a first optical signal from the network at an uncoupling point in a fiber connection of the network ahead of said part of the network, said first optical signal being a fraction of the distributed optical signal; a second uncoupling means for uncoupling the second optical signal from the network at or near the uncoupling point, said second optical signal being at least a fraction of signals reflected in said part of the network being monitored; first and second photo/electrical conversion means for separately converting said first and second optical signals to first and second electrical signals, respectively; and correlation means for correlating the second electrical signal with the first electrical signal and for supplying a signal for optical time-domain reflectometry in that part of the optical transmission network which is to be monitored.

Claim 7

A device for monitoring, by means of fault location with the aid of optical time-domain reflectometry based on correlation, at least a part of an optical transmission network comprising at least one optical fibre connection for distributing an optical signal, modulated with a data signal, from a transmitter connected to the optical transmission network to at least one receiver, the device comprising: a first uncoupling means for uncoupling a first optical signal from the network at an uncoupling point in a fiber connection of the network ahead of said part of the network, said first optical signal being a fraction of the distributed optical signal; a second uncoupling means for uncoupling the second optical signal from the network at or near the uncoupling point, said second optical signal being at least a fraction of signals reflected in said part of the network being monitored; first and second photo/electrical conversion means for separately converting said first and second optical signals to first and second electrical signals, respectively; and correlation means for correlating the second electrical signal with the first electrical signal and for supplying a signal for optical time-domain reflectometry in that part of the optical transmission network which is to be monitored.

Claim 11

A device for monitoring by means of fault location with the aid of optical time-domain reflectometry based on correlation, at least a part of an optical transmission medium comprising at least one optical fibre connection for distributing an optical signal, modulated with a data signal, of a transmitter connected to the optical transmission medium to at least one receiver, the device comprising: optical uncoupling means provided with a first optical signal output and a second optical signal output, respectively, for coupling at least a fraction of the optical modulated signal and at least a fraction of the reflected signal out of a fibre connection in the optical transmission medium; first signal derivation means for deriving a first signal corresponding to the modulated optical signal transmitted in the direction of the at least one receiver; second signal derivation means for deriving a second signal corresponding to a signal reflected in that part of the optical transmission medium which is to be monitored, the first and the second signal derivation means including opto/electrical converters coupled, respectively, to the first and the second signal output of the uncoupling means; correlation means for correlating the second signal with the first signal and for supplying a signal for optical time-domain reflectometry in that part of the optical transmission medium which is to be monitored; wherein the uncoupling means comprise a combined coupler/splitter provided with two input ports and two output ports, of which a first input port forms the first optical signal output and a first output port forms the second optical signal output, and the second input port and the second output port can be connected to fibre ends of a fibre connection which is opened at the selected uncoupling point.

Claim 12

A device for monitoring by means of fault location with the aid of optical time-domain reflectometry based on correlation, at least a part of an optical transmission medium comprising at least one optical fibre connection for distributing an optical signal, modulated with a data signal, of a transmitter connected to the optical transmission medium to at least one receiver, the device comprising: optical uncoupling means provided with a first optical signal output and a second optical signal output, respectively, for coupling at least a fraction of the optical modulated signal and at least a fraction of the reflected signal out of a fibre connection in the optical transmission medium; first signal derivation means for deriving a first signal corresponding to the modulated optical signal transmitted in the direction of the at least one receiver; second signal derivation means for deriving a second signal corresponding to a signal reflected in that part of the optical transmission medium which is to be monitored, the first and the second signal derivation means including opto/electrical converters coupled, respectively, to the first and the second signal output of the uncoupling means; correlation means for correlating the second signal with the first signal and for supplying a signal for optical time-domain reflectometry in that part of the optical transmission medium which is to be monitored; wherein the uncoupling means comprise a combined coupler/splitter provided with two input ports and two output ports, of which a first input port forms the first optical signal output and a first output port forms the second optical signal output, and the second input port and the second output port can be connected to fibre ends of a fibre connection which is opened at the selected uncoupling point.