Optical amplifying apparatus for wavelength division multiplexed signals

An optical amplifying apparatus for amplifying wavelength division multiplexed signals, comprising:

• an optical amplifying unit amplifying an output light;
• an output branching unit branching the output light;
• an optical filter passing a specific wavelength of the branched light;
• a specific wavelength measuring unit measuring a power of filtered light;
• a total power measuring unit measuring a total light power of the branched light;
• and
• a control unit controlling the optical amplifying unit based on the power of the filtered light and the total light power measured by the specific wavelength measuring unit and the total power measuring unit, respectively,
• wherein the control unit determines whether a change in output light is caused by a loss of transmission path or a change in wavelength number by comparing a first change of the power of the filtered light with a second change of the total light power.

An optical amplifying apparatus for amplifying wavelength division multiplexed signals, comprising:

• a first optical amplifying unit amplifying an input light;
• a second optical amplifying unit amplifying light outputted by the first optical amplifying unit;
• a first input branching unit branching the input light;
• a second output branching unit branching an output light of the second optical amplifying unit;
• a first optical filter passing a specific wavelength of the branched input light;
• a second optical filter passing a specific wavelength of the branched output light;
• a first specific wavelength measuring unit measuring a power of filtered input light;
• a second specific wavelength measuring unit measuring a power of filtered output light;
• a first total power measuring unit measuring a total input light power of the branched input light;
• a second total power measuring unit measuring a total output light power of the branched output light;
• and
• a control unit controlling the optical amplifying units based on the power of filtered input light, the power of filtered output light, the total light power of the branched input light, and a total light power of the branched output light measured by the first and second specific wavelength measuring units and the first and second total power measuring units,
• wherein the control unit determines whether a change of the output light is caused by a loss of transmission path or a change in wavelength number in the first or the second amplifier, by comparing a first change of the power of the filtered input light with a second change of the total input light power, and a third change of the power of the filtered output light with a fourth change of the total output power.

An optical amplifying apparatus for amplifying wavelength division multiplexed signals, comprising:

• a power measuring unit measuring a total light power of branched light which is branched from the wavelength division multiplexed signals, and light power of the branched light corresponding to a predefined wavelength range;
• and
• a control unit controlling an optical amplifying unit based on the light power of branched light corresponding to the predefined wavelength range, and the total light power of the branched light,
• wherein the control unit determines whether a change of output light is caused by a loss of transmission path or a change in wavelength number by comparing a first change of the light power of branched light corresponding to the predefined wavelength range with a second change of the total light power.