Fault localization apparatus for optical line in wavelength division multiplexed passive optical network

A fault localization apparatus for an optical line in a wavelength division multiplexed passive optical network (WDM PON) comprising:

• a central office including a multiplexer connected to downstream transmitters and a demultiplexer connected to upstream receivers;
• a remote node including a multiplexer/demultiplexer connected to the multiplexer and the demulitplexer through a first optical lines and passive elements;
• and
• optical network units connected to the multiplexer/demultiplexer through a plurality of second optical lines, respectively,
• wherein a channel exhibiting an abnormal receiving state of signals received by each of the upstream receivers is checked, a monitoring optical signal is inputted to the multiplexer of the central office, in which the monitoring optical signal is generated as a pulse is inputted to a light source of an downstream transmitter corresponding to the channel showing such an abnormal receiving state, such that, according to time while the monitoring optical signal is transmitted through the first optical line and the second optical lines, monitoring signal magnitude is measured to detect light loss and fault positions.

A fault localization apparatus for an optical line in wavelength division multiplexed passive optical network (WDM PON) comprising:

• a central office including a multiplexer connected to downstream transmitters and a demultiplexer connected to upstream receivers;
• a remote node including a demultiplexer connected to the multiplexer of the central office through a first optical line, and a mulitplexer connected to the demultiplexer of the central office through a second optical line which is installed therein together with the first optical line;
• and
• optical network units, each of which includes a downstream receiver connected to the demultiplexer of the remote node through a third optical line and an upstream transmitter connected to the multiplexer of the remote node through a fourth optical line which is installed therein together with the third optical line,
• wherein a channel exhibiting an abnormal receiving state of signals received by each of the upstream receivers is checked, a monitoring optical signal is inputted to the multiplexer of the central office, in which the monitoring optical signal is generated as a pulse is inputted to a light source of a downstream transmitter corresponding to the channel showing such an abnormal receiving state, such that, according to time while the monitoring optical signal is transmitted through the first optical line or the third optical lines, monitoring signal magnitude is measured to detect light loss, thereby detecting light loss and fault positions.

A fault localization apparatus for an optical line in a wavelength division multiplexed passive optical network (WDM PON) comprising:

• a central office including a multiplexer/demultiplexer whose ports are connected to a passive element and a set of a downstream transmitter and an upstream receiver;
• a remote node including a multiplexer/demultiplexer connected to the multiplexer/demulitplexer of the central office through a first optical lines;
• and
• optical network units connected to a second multiplexer/demultiplexer of the remote node through a plurality of second optical lines, respectively,
• wherein a channel exhibiting an abnormal receiving state of signals received by each of the upstream receivers is checked, a monitoring optical signal is inputted to the multiplexer/demultiplexer of the central office, in which the monitoring optical signal is generated as a pulse is inputted to a light source of a downstream transmitter corresponding to the channel exhibiting such an abnormal receiving state, such that, according to time while the monitoring optical signal is transmitted through the first optical line or the second optical lines, monitoring signal magnitude is measured to detect light loss and fault positions.

The fault localization apparatus for an optical line as set forth in claim 10, further comprising:

• a pulse generator generating pulses;
• a 2×1 switch connecting a data signal generator or the pulse generator with a light source of the downstream transmitter;
• a passive element, installed in an optical line connecting a downstream transmitter with passive elements, for changing paths of the monitoring optical signal outputted through the multiplexer/demultiplexer of the central office, which are scattered or reflected backwards;
• a controller checking whether the upstream receivers receive signals, and controlling the 2×1 switch such that a light source of a downstream transmitter is connected to the pulse generator if an abnormal receiving state is detected;
• and
• a receiver for monitoring signals for inputting the monitoring optical signals from the passive element, changing the inputted monitoring optical signals into electrical signals, converting magnitude variation of monitoring signals based on time lapse into optical loss values according to distance of the first optical line or the second optical line, and then outputting the converted values,
• wherein the fault localization apparatus is installed at each of the passive elements and a set of the downstream transmitter and the upstream receiver.