US 6,204,959 B1 · Signal light monitor and optical amplifier using the same

Abstract

A signal light monitor having a first optical branching coupler disposed in an optical fiber transmission line for branching a part of an inputted signal light and outputting a first branched light, a first wavelength tunable filter for transmitting a first particular wavelength component included in the first branched light and outputting a transmitted light and a first sweeper for sweeping a transmission center wavelength of the first wavelength tunable filter within a range of the first particular wavelength component. The transmitted light outputted from the wavelength tunable filter is received by a first optical receiver and converted into an electric signal and sampled by a first sampling device. The first sampling data is stored in a first storage device. A waveform of electric signal from optical receiver is stored in the first storage device as a series of data. Based on the stored sampling data, an arithmetic processing section detect an existence of light signal identifying a steep change in the waveform. The arithmetic processing section detects a level of light signalfrom a peak of the steep change and wavelength of signal light from the time difference between a time when the sweep of the wavelength tunable filter is started and a time when a peak level of the detected steep change is detected. The arithmetic processing section detects noise light level near signal light from the first waveform and calculates signal-to-noise ratio from the detected signal light level and the detected noise light level.

Claims20

Dependent claims

An optical amplifier signal light monitor comprising:

light amplifying means for amplifying an inputted signal light and outputting an amplified signal light;
an optical branching coupler, said optical branching coupler being disposed in an output side of said light amplifying means for branching a part of said amplified signal light and outputting a branched light;
a wavelength tunable filter for transmitting a particular wavelength component included in said branched light and outputting a transmitted light;
a sweeper for sweeping a transmission center wavelength of said wavelength tunable filter within a range of said particular wavelength component;
a optical receiver for receiving said transmitted light and converting said transmitted light into an electric signal;
sampling means for sampling said electric signal and outputting sampling data representative of a signal waveform;
a storage device for storing the sampling data;
and
an arithmetic processing means accessing the sampling data stored in the storage device and identifying the existence of signal light by detecting steep changes in said amplified signal light, said arithmetic processing means further including a means for detecting signal light level from peak level of said detected steep change.

6 more elements

An optical amplifier comprising:

light amplifying means for amplifying an inputted signal light and outputting an amplified signal light;
a first optical branching coupler, said first optical branching coupler being disposed in an output side of said light amplifying means for branching a part of an inputted signal light and outputting a first branched light;
a first wavelength tunable filter for transmitting a particular wavelength component included in said first branched light and outputting a first transmitted light;
a first sweeper for sweeping a transmission center wavelength of said first wavelength tunable filter within a range of said particular wavelength component;
a first optical receiver for receiving said transmitted light and converting said transmitted light into a first electric signal;
first sampling means for sampling said first electric signal and outputting first sampling data representative of a first signal waveform;
a first storage device for storing the first sampling data;
a second optical branching coupler, said second optical branching coupler being disposed in an input side of said light amplifying means for branching a part of an inputted signal light and outputting a second branched light;
a second wavelength tunable filter for transmitting a particular wavelength component included in said second branched light and outputting a second transmitted light;
a second sweeper for sweeping a transmission center wavelength of said second wavelength tunable filter within a range of said particular wavelength component;
a second optical receiver for receiving said transmitted light and converting said second transmitted light into a second electric signal;
second sampling means for sampling said second electric signal and outputting second sampling data representative of a second signal waveform;
a second storage device for storing the second sampling data;
an arithmetic processing means accessing said first and second sampling data in said first and second storage devices and identifying the existence of signal light by detecting steep changes in said first and second signal waveforms, said arithmetic processing means further including a means for detecting signal light level from peak level of said detected steep change;
and
signal light level control means responsive to said arithmetic processing means for controlling an output of said light amplifying means to maintain a signal level constant based on a result of detecting a signal light level by said arithmetic processing means.

13 more elements

Dependencies are inferred from the claim text.

Signal light monitor and optical amplifier using the same

Life of this patent

Signal light monitor and optical amplifier using the same

Life of this patent

Abstract

Claims20