JP2002062216A - Signal quality detecting device and signal wave amplifying system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a signal quality by respective channels and on the whole channels even in signal waves of the plural channels for multiplexing an input wave on a wave length. SOLUTION: This signal quality detecting device is provided with (1) a signal wave wave length component taking-out means for taking out a wave length component of the signal waves from the input wave and (2) a signal quality estimating means for determining the signal quality by estimating power of the signal waves and power of a noise wave by using a difference in a polarization characteristic between the signal waves and the noise wave from a signal wave wave length component wave taken out by the signal wave wave length component taking-out means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal quality detecting device and a signal wave amplifying system.
M: Wavelength Division Multiplexing (M: Wavelength Division Multiplexing) can be applied to an optical amplification repeater system and a WDM optical network system.

[0002]

2. Description of the Related Art For example, in an optical amplifying repeater system or an optical network system, a signal light to be propagated is amplified, and a signal-to-noise ratio (SNR: Signal) of the amplified signal light is amplified. As an SNR measuring apparatus for measuring a noise ratio, there is an apparatus disclosed in the above-mentioned document 1.

This SNR measuring apparatus separates a signal light including an amplified noise light into a signal light having the same wavelength as that of the signal light and a component wave having other wavelengths, thereby dividing the signal light into a signal light and a noise light. The SNR is obtained from the power level of the divided signal light and the power level of the noise light.

[0004]

Recently, from the viewpoint of speeding up a network, recently, a WDM optical amplifying repeater system and a WDM optical network system for transmitting and receiving wavelength division multiplexed (WDM: Wavelength Division Multiplexing) light have been proposed. Has been built. Also, with the expansion of networks, in these systems, a function of measuring a wavelength or monitoring the state of a signal (for example, the SNR of signal light) is indispensable in these systems in order to ensure service quality.

However, in the conventional SNR measuring device, the SNR of one signal light is measured or the SNR is measured.
Noise figure of optical amplifier (NF: Noise) for wave signal light
Figure 2) can be measured, and there is a problem that, for a multiplexed signal light of two or more waves, the SNR and NF for each signal light are not obtained but only the total SNR and NF are monitored. . That is, an apparatus for measuring SNR and NF for each channel from wavelength-multiplexed multiplexed signal light of a plurality of channels has not been proposed yet. In general, in a multiplexed signal light communication system, the communication quality to be monitored for each channel is S
In addition to NR and NF, there are signal interruption, signal light output power, and the like.

Therefore, even if the input wave is a multiplexed signal light or the like,
There is a need for a signal quality detection device capable of obtaining signal quality for a predetermined signal wave component, and a signal wave amplification system including such a signal quality detection device.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, a first aspect of the present invention is a signal quality detection for detecting the quality of a signal wave in an input wave having a polarized signal wave and a non-polarized noise wave. In the apparatus, (1) a signal wave wavelength component extracting means for extracting a wavelength component of a signal wave from the input wave, and (2) a signal wave and noise from the signal wave wavelength component wave extracted by the signal wave wavelength component extracting means. Signal quality estimating means for estimating the signal quality by estimating the power of the signal wave and the power of the noise wave using the difference in the polarization characteristics of the waves.

A second aspect of the present invention is a signal quality detecting device for detecting the quality of a signal wave in an input wave having a polarized signal wave and a non-polarized noise wave. A component wave extracting means for extracting a first component wave having the same wavelength as the signal wave and a second component wave near the wavelength of the signal wave;
(2) Estimating the power of the noise wave in the wavelength component of the signal wave from the second component wave extracted by the component wave extracting means, and estimating the power of the signal wave from at least the first component wave, And signal quality estimating means for determining

Further, the present invention in a third aspect of the present invention is a signal wave amplifying system provided with amplifying means for amplifying a signal wave, (1) a branching means for splitting a signal wave into two at a stage before or after the amplifying means; (2) The signal quality detecting device according to the first or second aspect of the present invention, wherein one of the signal waves output from the branching means is an input wave.

[0010] Still further, according to a fourth aspect of the present invention, there is provided a signal wave amplifying system comprising amplifying means for amplifying a signal wave.
(1) branching means for splitting a signal wave into two, and (2) a first or second book having one signal wave output from each of the branching means as an input wave, at a stage before and after the amplifying unit, respectively. And a signal quality detection device according to the invention.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) First Embodiment A WDM optical amplifier for amplifying and relaying a multiplexed signal light of a plurality of wavelength-multiplexed channels using a signal quality detection apparatus and a signal wave amplification system according to the present invention will be described below. A first embodiment applied to a relay system will be described in detail with reference to the drawings.

(A-1) Configuration of First Embodiment FIG. 1 is a block diagram showing the configuration of a WDM optical amplification repeater system according to this embodiment.

In FIG. 1, this WDM optical amplifying and repeating system comprises an optical amplifier 1, an optical coupler 2, a wavelength separation filter (for example, an AWG (Arraied Waveguide Grating) filter) 3, an optical switch 4, an automatic polarization plane controller, and the like. 5, Ramipole (analyzer) 6, and photodiode 7
And a resistor 8 and an analog / digital (A / D) converter 9
And a CPU (microprocessor) 10.

Here, an optical coupler 2, a wavelength separation filter 3, an optical switch 4, an automatic polarization plane controller 5, a Ramipole 6, a photodiode 7 and a resistor 8, an A / D converter 9, and a CPU 10 The signal quality detection device according to the embodiment is configured.

Multiplexed signal light obtained by wavelength-multiplexing signal light of a plurality of channels is incident on the optical amplifier 1.
The multiplexed signal light (signal light of each channel) is directly amplified without performing photoelectric conversion and light-to-light conversion. The optical amplifier 1 can adjust the amplification factor (gain) of the signal light of each channel based on the gain control signal from the CPU 10. As the optical amplifier 1, for example, an optical fiber amplifier can be applied.

The amplified multiplexed signal light contains wavelength components (noise components) other than the signal light depending on the amplification method, and most of such noise components are spontaneously emitted amplified light (A
SE: Amplified Spontaneous Emission)
Hereinafter, such a noise component is referred to as ASE light. The amplified multiplexed signal light is output via the optical coupler 2 to a main waveguide (not shown) such as an optical fiber.

The multiplexed signal light to the optical amplifier 1 is premised on polarized light. However, the multiplexed signal light may be such that the plane of polarization slowly rotates with time. The optical amplifier 1 is intended to maintain the polarization plane of the multiplexed signal light.

The optical coupler 2 has an AS amplified by the optical amplifier 1.
The multiplexed signal light including the E light is split into two systems so that the power ratio of each wavelength component included in the multiplexed signal light does not change. One of the branched multiplexed signal lights is output to a main waveguide (not shown), and the other multiplexed signal light is provided to a wavelength separation filter 3.

The wavelength separation filter 3 separates the multiplexed signal light provided from the optical coupler 2 into component light for each wavelength of the signal light of each channel (consisting of signal light of each channel and ASE light of the wavelength). Is what you do.

The optical switch 4 extracts the component light of one channel from the component light of each wavelength of each channel separated by the wavelength separation filter 3 based on the channel selection signal from the CPU 10.

The automatic polarization plane controller 5 rotates the polarization plane of the component light of the channel extracted by the optical switch 4 based on the polarization plane control signal from the CPU 10.

The Ramipole (analyzer) 6 passes only a predetermined one-way polarization plane component of the component light from the automatic polarization plane controller 5.

The photodiode 7 and the resistor 8 are provided as photoelectric conversion means. The photodiode 7 supplies a current according to the power of the component light passing through the Ramipole 6, and the resistor 8 controls the current. Is converted into a voltage and supplied to the A / D converter 9.

The A / D converter 9 converts an analog voltage signal given from a photoelectric conversion means comprising a photodiode 7 and a resistor 8 into a digital signal.

The CPU 10 controls the operation of each unit for detecting the signal quality and determines a signal quality value for a desired monitor item. In this embodiment,
The gain of the optical amplifier 1 is also controlled according to the detected quality result. Note that a DSP or the like may be applied instead of the CPU. As described above, the CPU 10 controls the channel of the component light extracted by the optical switch 4 based on the channel selection signal. In addition, the CPU 10
Controls the amount of rotation of the polarization plane of the input component light in the automatic polarization plane controller 5 by the polarization plane control signal. CPU
Reference numeral 10 denotes the power of the ASE light uniformly distributed without being limited to the predetermined polarization direction, based on the digital signal from the A / D converter 9 (that is, the power of the component light passing through the Ramipole 6). The power of the signal light distributed only in the polarization direction is estimated, and a signal quality value for a desired monitoring item is obtained for the currently targeted channel.

Here, the CPU 10 appropriately controls the channel selection signal and the polarization control signal, sequentially accesses each channel sequentially, and obtains a signal quality value for a desired monitoring item for each channel. .

Further, the CPU 10 creates a gain control signal based on the obtained signal quality value, and changes the amplification factor to be amplified by the optical amplifier 1 for each channel. CPU10
Is to output an alarm signal if the obtained signal quality value indicates a signal quality abnormality. For example, when the obtained SNR becomes low, control is performed so that the amplification factor of the channel becomes high. Detect and output alarm signal.

(A-2) Operation of the First Embodiment Next, the operation of the signal quality detection device of the first embodiment having the above configuration will be described with reference to the drawings.

Generally, the level of the ASE light having the same wavelength as the signal light cannot be directly measured because it overlaps with the signal light component.

Here, FIGS. 2 to 4 show, in order to briefly explain the operation principle of the first embodiment, one-channel component light (signal light and ASE light having the same wavelength as the signal light) is automatically polarized. FIG. 4 is a punch diagram showing a state before and after passing through a wavefront controller 5 and a Ramipole 6.

FIG. 2 shows a power distribution for each polarization plane of the component light at the point (A) in FIG. Of the component light of a certain channel extracted by the optical switch 4, the signal light has a plane of polarization in a certain direction, and has a power level only in that direction. FIG. 2 shows a case where the direction is the y-axis direction. On the other hand, the ASE light has a random plane of polarization in each direction (no polarization) and has a constant power level in any direction. In FIG. 2, for simplicity, 45 × N ゜ (N = 0)
Only the direction components of (7) to (7) are shown.

Here, when the polarization plane of the component light is rotated by the automatic polarization controller 5 and the polarization plane of the signal light in the component light coincides with the detection axis of the Ramipole 6 (see FIG. 2). When the y-axis coincides with the detection axis of the Ramipole 6), the power Pa of the component light output from the Ramipole 6 (output at the point (B) in FIG. 1) is, as shown in FIG. Optical power Ps and ASE in each direction (each polarization plane)
It becomes the total sum Pny of the component powers of the light parallel to the y-axis. That is, equation (1) holds. The power Pa of the component light output from the Ramipole 6 at this time becomes the maximum value when the automatic polarization plane controller 5 rotates the polarization plane variously because the signal light power Ps exists.

Pa = Ps + Pny (1) On the other hand, the polarization plane is rotated by the automatic polarization plane controller 5,
When the detection axis of the Ramipole 6 coincides with the x-axis in FIG. 2, the power Pb of the component light output from the Ramipole 6
Is as shown in FIG. 4 and as shown in equation (2),
It becomes the total sum Pnx of the component power parallel to the x-axis in the ASE light in each direction (each polarization plane).

Pb = Pnx (2) Here, if the ASE light has a random polarization component (polarization component), the ASE power Pny parallel to the y-axis and the ASE power Pnx parallel to the x-axis are equal. Total AS
Since half of the E power Pnt is Pnt / 2, the signal light power Ps and the noise power Pnt can be expressed by the equations (3) and (4), respectively. Also, the signal-to-noise ratio S
NR can be represented by equation (5).

Ps = (Ps + Pny) −Pnx = Pa−Pb (3) Pnt = 2 × Pny = 2 × Pnx = 2 × Pb (4) SNR = Ps / Pnt = (Pa−Pb) / (2 × Pb) (5) As the signal light power in the signal-to-noise ratio SNR, there is a case where the signal light power including the noise power of the wavelength component is also used. However, the signal-to-noise ratio SNR in the above equation (5) is the signal light power , Which does not include the noise power of the wavelength component.

That is, the CPU 10 controls the optical switch 4 to input the component light of the channel to be detected at that time to the automatic polarization plane controller 5, and thereafter, the automatic polarization plane controller 5 The polarization plane is rotated, the maximum value of the digital signal from the A / D converter 9 (corresponding to the above Pa) is detected, and if the maximum value of the digital signal is detected, the automatic polarization plane controller 5 at the time of the detection is detected. , The polarization plane is rotated by 90 ° from the rotation position of the polarization plane, and the value of the digital signal (corresponding to the above Pb) from the A / D converter 9 at that rotation position is acquired.

Thereafter, the CPU 10 calculates a desired signal quality value. For example, if the desired signal quality is the signal light power Ps or the noise power Pnt, the above Pa or Pb
Is obtained according to the equations (3) and (4) based on the obtained digital value corresponding to Also at this time, the optical amplifier 1
May be appropriately controlled. Further, for example, if the desired signal quality is the signal-to-noise ratio SNR, it is obtained according to the equation (5) based on the obtained digital values corresponding to the above Pa and Pb. Also at this time, the amplification factor control of the optical amplifier 1 may be appropriately performed. Further, for example, if the desired signal quality is the interruption of the signal light,
The signal light power Ps is obtained according to the equation (3), and the signal light power Ps is compared with a threshold. When a signal interruption is detected, the CPU 10 outputs an alarm signal.

While the processing for one certain channel has been described above, the CPU 10 controls the optical switch 4 to
The component light channel selected by the optical switch 4 is switched, and a desired signal quality value is obtained for the other channels by the same processing as described above. When the detection processing for all channels is completed in this way, information such as the number of channels in the input multiplexed signal light, the presence or absence of signals of each channel, and unused wavelengths can be obtained.

(A-3) Effects of the First Embodiment As described above, according to the first embodiment, (1) a given multiplexed signal light is separated into component lights for each channel of each wavelength. A wavelength separation filter 3 and an optical switch 4 for extracting component light of one channel based on a channel selection signal from the CPU 10, and (2) a polarization plane control from the CPU 10 for component light of the channel extracted by the optical switch 4. An automatic polarization plane controller 5 and a Ramipole 6 for controlling the rotation of the plane of polarization based on the signal and passing only the polarization plane component in a certain direction; and (3) the power level of the light passing through the Ramipole 6 Estimating the power of the ASE light uniformly distributed without being limited to the predetermined direction and the power of the signal light distributed only in the predetermined polarization direction to obtain a desired signal quality value for each channel With the CPU 10, it is possible to obtain only the signal quality of the desired channel for the wavelength multiplexed light, and it is also possible to easily obtain the signal quality of all the channels.

(A-4) Modification of First Embodiment In the first embodiment, the signal quality value for the multiplexed signal light on the output side of the optical amplifier 1 is detected. It may be provided on the input side of the optical amplifier 1 to detect the signal quality value for the multiplexed signal light on the input side of the optical amplifier 1. Further, a configuration for detecting a signal quality value for multiplexed signal light may be provided on both the input side and the output side of the optical amplifier 1. In this case, if the CPU (10) in the detection configuration on the input side and the output side is shared, the noise figure NF of each channel via the optical amplifier 1 can also be obtained.

When the signal quality value detection structure for the multiplexed signal light is provided on both the input side and the output side of the optical amplifier 1, the separated multiplexed signal light from the optical coupler for separating the multiplexed signal light on the input side is used. If an optical switch for selecting the separated multiplexed signal light from the optical coupler (2) for separating the multiplexed signal light on the output side is provided, the wavelength separating filter (3)
The portion U (10) can be shared as an input side and output side detection configuration.

Further, in the first embodiment, the automatic polarization plane controller 5 is provided to change the polarization plane of the component light of each channel output from the Ramipole 6, but the automatic polarization plane controller 5 is omitted. And Ramipole 6
May be rotated so that the polarization plane of the component light of each channel output from the Ramipole 6 may be changed.

(B) Second Embodiment Next, a signal quality detecting device and a signal wave amplifying system according to the present invention are applied to a WDM optical amplifying and repeating system for amplifying and relaying a multiplexed signal light of a plurality of wavelength-multiplexed channels. A second embodiment applied to the invention will be described in detail with reference to the drawings.

(B-1) Configuration of Second Embodiment FIG. 5 is a block diagram showing the configuration of a WDM optical amplifying repeater system according to the second embodiment. The same or corresponding parts as those in FIG. 1 are denoted by the same or corresponding reference numerals. In FIG. 5 as well, the components excluding the optical amplifier 1 constitute a signal quality detection device.

In FIG. 5, the WD of the second embodiment
In the M optical amplification relay system, the optical amplifier 1, the optical coupler 2, the wavelength separation filter 3, the optical switch 4, and the automatic polarization controller 5 are the same as those in the first embodiment.

In the second embodiment, a polarization separation prism 6A is provided downstream of the automatic polarization plane controller 5. The polarization splitting prism 6A separates and extracts two orthogonal polarization plane components of the component light from the automatic polarization plane controller 5. As the polarization splitting prism 6A, for example, a Glan-Thompson prism utilizing the birefringence characteristic of calcite is used.
ism), a Wollaston prism, a lotion prism, and the like.

Photodiode 7P, resistor 8P and A /
The D converter 9P photoelectrically converts one component light from the polarization splitting prism 6A and converts the component light into a digital signal.
This is input to the PU 10. The photodiode 7S, the resistor 8S, and the A / D converter 9S photoelectrically convert the other component light from the polarization splitting prism 6A and convert it into a digital signal, which is input to the CPU 10.

(B-2) Operation of the Second Embodiment In the second embodiment, the principle of detecting a desired signal quality value (value of a desired monitoring item) is the same as that of the first embodiment. It is. That is, the above description with reference to FIGS. 2 to 4 holds, and a desired signal quality value (a value of a desired monitoring item) is detected according to the above-described equations (3) to (5).

Here, in order to obtain a signal quality value according to the equations (3) to (5), two kinds of powers Pa and Pb are required. As described above, the power Pa is the power in the polarization component parallel to the polarization plane of the signal light in the component light from the automatic polarization controller 5, and is the power of each polarization component in the component light from the automatic polarization controller 5. The power Pb is the power of the component of the component light from the automatic polarization controller 5 in the polarization plane component orthogonal to the polarization plane of the signal light.

In the first embodiment, the CPU 10
Controls the automatic polarization plane controller 5 to first detect the power Pa (maximum power), and then rotates the component light by 90 ° by the automatic polarization plane controller 5 to detect the power Pb.

On the other hand, in the second embodiment, the CPU 10 controls the A / D converter 9 while rotating the polarization plane of the component light by the automatic polarization plane controller 5.
The maximum value (corresponding to the power Pa) of the digital signal from P is searched, and the value of the digital signal from the other A / D converter 9S at the time when the maximum value is searched is taken in simultaneously as the value related to the power Pb. From the powers Pa and Pb thus obtained, a desired signal quality value is obtained.

Here, such simultaneous detection of the powers Pa and Pb is based on the application of the polarization splitting prism 6A instead of the Ramipole 6. That is, when the component of the component light from the automatic polarization controller 5 that is parallel to the polarization plane of the signal light coincides with one of the passing polarization planes of the polarization splitting prism 6A, the component light from the automatic polarization controller 5 , The polarization plane component orthogonal to the polarization plane of the signal light coincides with the other passing polarization plane of the polarization splitting prism 6A, and the powers Pa and Pb can be detected simultaneously.

(B-3) Effects of the Second Embodiment Also in the second embodiment, the basic technical idea and configuration for detecting a signal quality value are the same as those in the first embodiment. The same effects as in the first embodiment can be obtained.

In addition, according to the second embodiment,
Since the powers Pa and Pb for obtaining the signal quality value are simultaneously detected, the signal quality value can be obtained with high accuracy even if the power fluctuates over time.

(B-4) Modification of Second Embodiment In the second embodiment shown in FIG. 5, in order to simultaneously detect the powers Pa and Pb, the polarization splitting prism 6A is used.
However, instead of the polarization splitting prism 6A, an optical coupler that splits the component light from the automatic polarization plane controller 5 into two, and one that passes one of the orthogonal polarization plane components of each split component light, is used. You may make it apply to a piece of Ramipole.

(C) Third Embodiment Next, a signal quality detection device and a signal wave amplification system according to the present invention are applied to a WDM optical amplification relay system that amplifies and relays a multiplexed signal light of a plurality of wavelength-multiplexed channels. A third embodiment applied to the invention will be described in detail with reference to the drawings.

(C-1) Configuration of the Third Embodiment FIG. 6 is a block diagram showing the configuration of a WDM optical amplifying and repeating system according to the third embodiment, which is related to the above-described first embodiment. The same or corresponding parts as those in FIG. 1 are denoted by the same or corresponding reference numerals. In FIG. 6, components other than the optical amplifier 1 constitute a signal quality detection device.

Referring to FIG. 6, the WD of the third embodiment
The M optical amplifying repeater system includes an optical amplifier 1 and an optical coupler 2
, Wavelength separation filter 3, automatic polarization plane controller 5
, Ramipol 6-1 to 6-n, and photodiode 7
-1 to 7-n, resistors 8-1 to 8-n, A / D converters 9-1 to 9-n, and a CPU 10.

As shown in FIG. 6, in the third embodiment, an automatic polarization plane controller 5 is moved to a stage preceding the wavelength separation filter 3 in FIG. The optical switch 4 for extracting one of the channel components is omitted, and the Ramipoles 6-1 to 6-n corresponding to the output ports of all the channels from the wavelength separation filter 3 are omitted.
And photodiodes 7-1 to 7-n and resistors 8-1 to 8
-N and A / D converters 9-1 to 9-n.

The components of the third embodiment are the same as those having the same names as those of the first embodiment, and the description of the functions will be omitted.

(C-2) Operation of the Third Embodiment The operation of the third embodiment will be briefly described below, focusing on the differences from the first embodiment.

It is desirable to monitor the signal quality such as whether or not the signal light of each channel is interrupted as continuously as possible. However, in the first embodiment, each channel is selected by the optical switch 4, and each time the polarization controller 5 rotates and detects the polarization plane, the detection takes time.

For this reason, in the third embodiment, the automatic polarization plane controller 5 is provided before the wavelength separation filter 3, so that the polarization planes of the signal light and the ASE light of each channel are collectively rotated and controlled. , The optical switch 4 is deleted, and the Ramipoles 6-1 to 6-
n, photodiodes 7-1 to 7-n, resistors 8-1 to 8
By providing -n and A / D converters 9-1 to 9-n, each channel can be continuously monitored. Note that the operation principle is the same as in the first embodiment.

Here, a CPU capable of performing parallel processing is applied as the CPU 10 (for example, the CPU 10 is not limited to one chip, but may be constituted by a plurality of chips.

(C-3) Effects of Third Embodiment As described above, according to the third embodiment, the same effects as those of the first embodiment are obtained.

According to the third embodiment, (1) the automatic polarization controller 5 is different from the configuration of the first embodiment.
To the preceding stage of the wavelength separation filter 3, (2) the optical switch 4 for extracting one channel component of each channel is deleted, and (3) the Ramipole corresponding to the output ports of all the channels from the wavelength separation filter 3. 6-1 to 6-n, photodiodes 7-1 to 7-n, and resistors 8-1 to 8-n and A
Since the / D converters 9-1 to 9-n are provided, in the signal quality detection of each channel, the switching of the optical switch 4 eliminates the waiting time until the same channel is connected, and the automatic biasing is performed. Since it takes only a short time for the wavefront controller 5 to make one rotation, monitoring can be performed in a more continuous state.

Further, according to the third embodiment, the optical switch 4 becomes unnecessary, and the number of rotations of the automatic polarization plane controller 5 is reduced to one-sixth of the number of channels. The performance is improved.

(C-4) Modification of Third Embodiment Ramipol 6-N (N is 1) in each channel shown in FIG.
To n) to A / D converter 9-N,
The embodiment may be replaced with a reconfiguration using a polarization splitting prism as in the embodiment.

(D) Fourth Embodiment Next, a signal quality detecting device and a signal wave amplifying system according to the present invention are applied to a WDM optical amplifying and repeating system for amplifying and relaying a multiplexed signal light of a plurality of wavelength-multiplexed channels. A fourth embodiment applied to the invention will be described in detail with reference to the drawings.

(D-1) Configuration of the Fourth Embodiment FIG. 7 is a block diagram showing the configuration of a WDM optical amplifying and repeating system according to the fourth embodiment. The same and corresponding parts as those in FIG. 6 are denoted by the same and corresponding reference numerals. In FIG. 7, the components excluding the optical amplifier 1 also constitute a signal quality detection device.

In FIG. 7, the WD of the fourth embodiment
The M optical amplifying repeater system includes an optical amplifier 1 and an optical coupler 2
, Wavelength separation filter 3A, automatic polarization plane controller 5, Ramipoles 6-1 to 6- (n + α), photodiodes 7-1 to 7- (n + α), and resistors 8-1 to 8-
(N + α) and A / D converters 9-1 to 9- (n + α)
And a CPU 10.

As shown in FIG. 7, in the fourth embodiment, n-channel component light (signal light and ASE light having the same wavelength as the signal light) are different from FIG. 6 showing the structure of the third embodiment. )
Is replaced by a wavelength separation filter 3A having an output port for separating (n + α) channel component light. Further, in addition to the n photodiodes, the n resistors, and the n A / D converters provided in the third embodiment, α photodiodes and α A / D converters are used. It has various mountable sockets and a package PKG with α resistors connected to the corresponding photodiode.

Here, the components to be packaged (for example, a printed wiring board) PKG are preferably configured to handle electric signals, so that an optical waveguide such as an optical fiber can be omitted. Also, since the resistance is easy to form on the package (for example, printed wiring board) PKG,
Initially, unused channels are prepared in advance.

The components of the fourth embodiment also have the same functions as the components of the third embodiment having the same names, and a description thereof will be omitted.

(D-2) Operation of the Fourth Embodiment Hereinafter, the operation of the fourth embodiment will be briefly described focusing on the differences from the third embodiment.

A wavelength separation filter 3 capable of coping with a larger number of channels than the initially required number of channels (number of wavelengths)
A is used. Also, for that extra channel,
Various sockets where a photodiode and an A / D converter can be mounted later, and α connected to the corresponding photodiode
A package PKG having a plurality of resistors is provided. When an unused wavelength (channel) is used, an additional photodiode and an A / D converter are inserted into a socket already incorporated in the package PKG, and a Ramipole is provided to use the wavelength separation. The output port of the filter is connected to the added Ramipole, and the output of the Ramipole is connected to the photodiode input.

On the other hand, the configuration added to cope with a new channel, when the channel is no longer used,
It can be removed by the reverse procedure described above.

As described above, the configuration can cope with the increase or decrease in the number of channels, but the operation principle at the time of detecting the signal quality value in each channel is the same as in the first embodiment.

(D-3) Effects of Fourth Embodiment As described above, according to the fourth embodiment, the same effects as those of the third embodiment can be obtained.

Further, according to the fourth embodiment, (1) a wavelength separation filter 3A having an output port for separating component light of the (N + α) channel from the configuration of the third embodiment, 2) Since there are various sockets capable of mounting α photodiodes and A / D converters and a package having α resistors connected to the photodiodes, the photodiodes can be replaced without replacing the wavelength separation filter. By simply inserting or removing the A / D converter and the Ramipole, the number of channels can be easily increased or decreased.

(E) Fifth Embodiment Next, a signal quality detecting device and a signal wave amplifying system according to the present invention are applied to a WDM optical amplifying and repeating system for amplifying and relaying a multiplexed signal light of a plurality of wavelength-multiplexed channels. A fifth embodiment applied to the invention will be described in detail with reference to the drawings.

(E-1) Configuration of Fifth Embodiment FIG. 8 is a block diagram showing a configuration of a WDM optical amplifying and repeating system of the fifth embodiment.

In FIG. 8, a WDM optical amplifying and repeating system according to the fifth embodiment comprises an optical amplifier 11 and an optical coupler 12.
, A wavelength separation filter 13, 2n + 1 photodiodes 14-1 to 14- (2n + 1), 2n + 1 resistors 15-1 to 15- (2n + 1), and 2n + 1 A
/ D converters 16-1 to 16- (2n + 1) and CPU 1
And 7. The components excluding the optical amplifier 11 constitute a signal quality detection device.

The optical amplifier 11 amplifies the wavelength-division multiplexed signal light when given a plurality of wavelength-multiplexed wavelength-division multiplexed signal lights (here, n channels). The optical amplifier 11 adjusts the amplification factor (gain) of the signal light of each channel based on the gain control signal from the CPU 17.

In the fifth embodiment as well, wavelength components (noise components) other than the signal light are mixed in the amplified multiplexed signal light, and most of such noise components are ASE light. Hereinafter, such a noise component is referred to as ASE light.

The optical coupler 12 branches the wavelength multiplexed signal light including the ASE light amplified by the optical amplifier 11 into two systems so that the ratio of the signal component contained in the wavelength multiplexed signal light does not change. . One of the branched wavelength multiplexed signal lights is output to a main waveguide (not shown), and the other is input to a wavelength separation filter 13.

The wavelength separation filter 13 converts the multiplexed signal light provided from the optical coupler 12 into a wavelength component of the signal light of each channel and a wavelength component (ASE) near the wavelength of each channel.
Light; specifically, ASE light having an intermediate wavelength between each channel, ASE light shorter than the shortest wavelength, and ASE light longer than the longest wavelength
(SE light).

The wavelength separation filter 13 has 2n + 1 output ports for the number n of channels. For example,
The length of the wavelength component to be separated from the size of the output port number is 1
One to one. Here, the wavelength of each channel is λ <
Assuming that x> (x is any one of 1 to n, and the smaller x is, the shorter the wavelength is), the wavelength component λ <x> of the signal light of each channel is output from the even-numbered 2x output port. The wavelength component (ASE light) of the intermediate wavelength (λ <x> + λ <x + 1>) / 2 between the channels is output from the output port of the odd number 2x + 1. From the output port of number 1, the wavelength component (AS) of (λ <1> −λ <2>) / 2
E light) is output from the output port of number 2n + 1.
A wavelength component (ASE light) of 3λ <2n> / 2 + λ <2n + 1>) / 2 is output.

Each photodiode 14-k (k is 1 to
(2n + 1)) passes a current based on the power of the component light from the k-th wavelength of the wavelength separation filter 13, and the resistor 15-k converts the current into a voltage to convert the current into a voltage.
6-k.

Each A / D converter 16-k converts an analog voltage from a photoelectric conversion means consisting of a photodiode 14-k and a resistor 15-k into a digital signal, and converts the analog voltage into a digital signal.
To give. The A / D converters 16-1 to 16-1
As 6- (2n + 1), for example, a commercially available product can be applied.

The CPU 17 has A / D converters 16-1 to 16-1.
Based on the digital signal given from 6- (2n + 1), a signal quality value for a desired monitoring item is obtained for each channel. The specific detection method will be clarified in the operation description described later. CPU 17
The amplification factor of the optical amplifier 11 is appropriately controlled based on the obtained signal quality value.

(E-2) Operation of Fifth Embodiment Next, the operation of the signal quality detection device of the fifth embodiment having the above-described configuration will be described with reference to the drawings.

FIG. 9 is an image diagram showing an optical spectrum after multiplexed signal light of each channel is amplified by the optical amplifier 11.

As shown in FIG. 9, the ASE power is slightly different depending on the wavelength. The power of the signal light wavelength of each channel is the sum of the power of the signal light itself and the ASE power. Not only does the ASE power slightly vary depending on the wavelength, but also the power of the signal light itself varies depending on the channel. Are not equal. Here, the ASE power of the same wavelength as the signal light cannot be directly measured because it overlaps with the signal component.

In the fifth embodiment, in consideration of the characteristic that the power of the ASE light has a gentle gradient (curve) with respect to the wavelength, the ASE having the same wavelength as the signal light is used by using the interpolation method.
The power of the light (hereinafter, sometimes referred to as “ASE light immediately below the signal”) is determined. That is, from the power of the ASE light near the signal wavelength, the AS
The power of the E light was estimated.

FIG. 10 shows a digital signal (electrical signal but corresponding to optical power from each A / D converter 16-k) for the wavelength multiplexed signal light shown in FIG. Power or ASE light power). The horizontal axis in FIG. 10 indicates the A / D converter 16-
k, the wavelength separation filter 13 corresponding one-to-one
Is indicated by the output port number k.

Here, in FIG. 10, x (x is 1 to
The power of the wavelength component of the (n) th signal light having the shortest wavelength (x channel) is represented by S <x>. Also, in FIG. 10, A (y is 1 to (n + 1)), which is the shortest wavelength
The power of the SE light is represented by N <y>.

The power Pnx of the ASE light immediately below the signal light in the channel of the wavelength λx can be estimated from the equation (6) by an interpolation method.

Pnx = (N <x> + N <x + 1>) / 2 (6) Since the power Pnx of the ASE light immediately below the signal light can be estimated by the equation (6), the signal light of the signal light itself in the channel of the wavelength λx is used. The power Psx can be estimated by equation (7).

Psx = S <x> − (N <x> + N <x + 1>) / 2 (7) If the desired signal quality is the signal-to-noise ratio SNRx for the x channel, (8) Estimate according to the formula.

SNRx = S <x> / ((N <x> + N <x + 1>) / 2) (8) It is to be noted that the signal light power in the signal-to-noise ratio SNRx excluding noise power is applied. When estimating the signal-to-noise ratio SNRx, instead of equation (8),
Equation (9) is to be followed.

SNRx = Psx / Pnx (9) As described above, the CPU 17 sets the A / D converters 16-1 to 16-1
Optical power S <1 at each wavelength from 16− (2n + 1)
> To S <n> and N <1> to N <n + 1> to obtain a desired signal quality value (value for a predetermined monitoring item). The desired signal quality value includes not only the signal light power, the ASE light power immediately below the signal, and the signal-to-noise ratio as described above, but also the number of channels included in the wavelength-division multiplexed signal light and the presence or absence of a signal of each channel Alternatively, unused wavelengths, signal interruptions, etc. may be used.

Further, the CPU 17 forms a gain control signal based on the obtained signal quality value, and changes the amplification factor of the optical amplifier 11 for each channel. Also, the CPU 17
Means that if the signal quality value falls below a certain value,
Outputs an alarm signal.

(E-3) Effect of Fifth Embodiment As described above, according to the fifth embodiment, (1) the given multiplexed signal light is converted into the signal light of each channel and the wavelength of each channel. Wavelength separation filter 13 for separating ASE light in the vicinity
And (2) the CPU 17 that estimates ASE light power of the same wavelength as the signal light of each channel from ASE light near the wavelength of each channel, and obtains a signal quality value from the estimated ASE light power and signal light power. Therefore, the output power level of the signal light of each channel and the presence / absence of a signal interruption can be monitored in parallel.

(E-4) Modification of Fifth Embodiment In the fifth embodiment, the signal quality value for the multiplexed signal light on the output side of the optical amplifier 11 is detected. It may be provided on the input side of the optical amplifier 1 to detect the signal quality value for the multiplexed signal light on the input side of the optical amplifier 1. May be provided. In this case, if the CPU (17) in the detection configuration on the input side and the output side is shared, the noise figure NF of each channel via the optical amplifier 11 is obtained.
Can also be requested.

In the above description, interpolation from two samples is shown, but interpolation using three or more samples may be used. Further, in the wavelength range of the wavelength multiplexed signal light, the power of the ASE light at a plurality of points is detected, and a change curve of the power of the ASE light in the wavelength range of the wavelength multiplexed signal light is detected from a plurality of detected samples. And the power of the ASE light immediately below the signal light may be obtained from the estimated curve.

(F) Sixth Embodiment Next, a signal quality detection device and a signal wave amplification system according to the present invention are applied to a WDM optical amplification repeater system for amplifying and relaying multiplexed signal light of a plurality of wavelength-multiplexed channels. A sixth embodiment applied to (1) will be described in detail with reference to the drawings.

(F-1) Configuration of the Sixth Embodiment FIG. 11 is a block diagram showing the configuration of a WDM optical amplifying and repeating system according to the sixth embodiment. The same and corresponding parts are denoted by the same and corresponding reference numerals. In FIG. 11, the portion excluding the optical amplifier 11 constitutes the signal quality detecting device.

In FIG. 11, the WDM of the sixth embodiment
The optical amplification relay system includes an optical amplifier 11 and an optical coupler 12.
, A wavelength separation filter 13 and a photodiode 14-
1-14- (n + 1) and resistors 15-1-15- (n +
1), A / D converters 16-1 to 16- (n + 1),
It has a CPU 17 and an optical switch 18.

As shown in FIG. 11, in the sixth embodiment, the ASE light from the odd-numbered output port of the wavelength separation filter 13 is connected to the optical switch 18. The optical switch 18 selects only one-port ASE light based on a port selection signal from the CPU 17. The photodiode 14- (n + 1), the resistor 15- (n + 1), and the A / D converter 16- (n + 1) perform photoelectric conversion and analog / digital conversion on the ASE light selected by the optical switch 18. is there.

As compared with the fifth embodiment, the sixth embodiment differs from the fifth embodiment in that a photodiode, a resistor and an A / D converter provided for each odd-numbered output port of the wavelength separation filter 13 are replaced by an optical signal. By adding the switch 18, the configuration is integrated into one.

The components of the sixth embodiment having the same names as those of the fifth embodiment have the same functions as those of the fifth embodiment, and a description thereof will be omitted.

(F-2) Operation of the Sixth Embodiment The operation of the sixth embodiment will be briefly described below, focusing on the differences from the fifth embodiment.

Depending on the signal quality (monitoring item) to be monitored, there is a signal that need not be constantly monitored. For example, it is desirable to monitor whether or not the signal light of each channel is interrupted as continuously as possible.
It is not always necessary to continuously monitor R and the like.
The sixth embodiment deals with signal quality (monitoring items) that does not need to be constantly monitored.

Further, the power of the ASE light immediately below the signal light is:
Since it is obtained by the interpolation method, the accuracy cannot be made very high. Even if there is a time lag when detecting the signal light power and when detecting the power of the ASE light to be used for the interpolation, it is obtained by the calculation. The accuracy of the power of the ASE light immediately below the signal light is almost the same as when there is no time lag.

Therefore, in the sixth embodiment,
A common photodiode 14- (n + 1), a resistor 15- (n + 1) and an A / D converter 16- (n + 1) are applied for detection of each ASE light power. 14- (n + 1),
The resistor 15- (n + 1) and the A / D converter 16- (n +
The connection port of the wavelength separation filter 13 connected to the 1) side is periodically switched. The switching cycle is synchronized with the port selection signal from the CPU 17 so as not to affect the calculation of the signal quality value.

(F-3) Effects of Sixth Embodiment As described above, according to the sixth embodiment, the same effects as those of the fifth embodiment can be obtained.

According to the sixth embodiment, (1) AS from the odd-numbered output port of the wavelength separation filter 13
The E light is connected to the optical switch 18, and (2) only the one-port ASE light based on the port selection signal from the CPU 17 is supplied to the photodiode 14- (n + 1) and the resistor 15- (n +
1) and (3) connected to the CPU 17 via the A / D converter 16- (n + 1), so that the photodiode, the resistor, and the A / D converter are not affected without affecting the processing. It is possible to reduce the number of vessels as compared with the fifth embodiment.

(G) Seventh Embodiment Next, a signal quality detecting device and a signal wave amplifying system according to the present invention are applied to a WDM optical amplifying and repeating system for amplifying and relaying a multiplexed signal light of a plurality of wavelength-multiplexed channels. A seventh embodiment applied to the invention will be described in detail with reference to the drawings.

(G-1) Configuration of the Seventh Embodiment FIG. 12 is a block diagram showing the configuration of a WDM optical amplification repeater system of the seventh embodiment. The same or corresponding parts as those in FIG. 11 according to the sixth embodiment are denoted by the same or corresponding reference numerals. In FIG. 12, the portion excluding the optical amplifier 11 constitutes a signal quality detecting device.

In FIG. 12, the WDM of the seventh embodiment
The optical amplification relay system includes an optical amplifier 11 and an optical coupler 12.
, Wavelength separation filter 13A, photodiode 14
-1 to 14- (n + 1 + α) and resistors 15-1 to 15-
(N + 1 + α) and A / D converters 16-1 to 16- (n
+ 1 + α), a CPU 17, and an optical switch 18.

As shown in FIG. 12, in the seventh embodiment, the signal components of n channels and the ASE of n + 1 points
Instead of the wavelength separation filter 13 of the sixth embodiment having an output port for extracting the component, the wavelength separation filter 13 having an output port for extracting the signal component of the (n + α) channel and the ASE component at the (n + 1 + α) point.
A is used. Further, in addition to the photodiode, the resistor, and the A / D converter that the sixth embodiment has, various sockets on which the α photodiodes and the A / D converter can be mounted, and a connection to the photodiode. It has a package PKG with α resistors.

The components of the seventh embodiment are the same as those of the fifth and sixth embodiments having the same names, and a description thereof will be omitted.

(G-2) Operation of the Seventh Embodiment The operation of the seventh embodiment will be briefly described below focusing on the differences from the fifth and sixth embodiments.

A wavelength separation filter 1 capable of coping with a larger number of channels (number of channels) than initially required.
3A is used. Also, the photodiodes 14- (n + 2) to 14- (n + 1 +
α) and A / D converters 16- (n + 2) to 16- (n +
1 + α) to be mounted later, and α resistors 15- (n + 2) to 1 connected to the photodiode.
A package PKG provided with 5- (n + 1 + α) is used.

When an unused wavelength (channel) is used, an additional photodiode and an A / D converter are inserted into a socket already incorporated in the package PKG, and the wavelength separation filter 13 is used. Output port to be connected to a photodiode. For example, for the first addition of a channel, the photodiode 14-
(N + 2) and the A / D converter 16- (n + 2) are added, and the output port used by the wavelength separation filter 13 is connected to the photodiode 14- (n + 2). In addition,
By the insertion of the photodiode 14- (n + 2), the photoelectric conversion means using the existing resistor 15- (n + 2) is completed.

The principle of detecting the signal quality value for the channel added in this way is the same as in the above-described sixth embodiment.

Note that the added channel can be returned to the unused channel. In this case, the process is performed in the reverse procedure.

(G-3) Seventh Embodiment As described above, according to the seventh embodiment, the same effects as in the sixth embodiment can be obtained.

Further, according to the seventh embodiment, (1)
A wavelength separation filter 13A having an output port for extracting a signal component of the (n + α) channel and an ASE component at the (n + 1 + α) point; and (2) various sockets capable of mounting α photodiodes and an A / D converter. And a package having α resistors connected to the photodiode, so that the number of channels can be increased or decreased only by inserting or removing the photodiode and the A / D converter without replacing the wavelength separation filter 13A. It can be done easily.

(H) Other Embodiments In each of the above embodiments, the signal quality value (for example, SN) of each channel is obtained from the wavelength-multiplexed multiplexed signal light of a plurality of channels.
R) is described, but the present invention is not limited to multiplexed signal light, and the present invention can be applied to one signal light.

In each of the above embodiments, the signal quality detection device is provided before or after the optical amplifier 1 or 11. However, the signal quality detection device is provided before and / or after other optical components other than the optical amplifier. It may be provided.

Furthermore, in each of the above embodiments, the signal quality of each channel is determined from the wavelength multiplexed signal light. However, for example, the signal quality of a signal wave in a radio electromagnetic wave such as a multiplex radio system is determined. However, the present invention is applicable. In the claims, "wavelength"
Is used, but also includes this modified example.

In each of the first to fourth embodiments,
Although the case where the polarization plane (polarization plane) of the ASE light is random (uniformly distributed in all directions) has been described, other than this case, the technical ideas according to the first to fourth embodiments are applied. can do. For example, the polarization plane of the ASE light is
If the distribution has a known distribution in advance (for example, an ellipse instead of a circle in FIG. 2), the ASE light power can be estimated without necessarily limiting to a uniform distribution.

[0135]

As described above, according to the signal quality detecting apparatus of the first aspect of the present invention, (1) signal wave wavelength component extracting means for extracting a wavelength component of a signal wave from an input wave; From the signal wavelength component wave extracted by the wave wavelength component extracting means,
Utilizing the difference between the polarization characteristics of the signal wave and the noise wave to estimate the power of the signal wave and the power of the noise wave, and having a signal quality estimating means for obtaining the signal quality, the input wave is wavelength-multiplexed. Even for a signal wave of a plurality of channels, the signal quality for each channel or for all channels can be obtained.

According to the signal quality detecting apparatus of the second aspect of the present invention, (1) the first component wave having the same wavelength as the signal wave and the second component wave near the wavelength of the signal wave are obtained from the input wave. And (2) estimating the power of the noise wave in the wavelength component of the signal wave from the second component wave extracted by the component wave extracting means and extracting the signal wave from at least the first component wave. And the signal quality estimating means for obtaining the signal quality, so that even if the input wave is a signal wave of a plurality of channels multiplexed with wavelength, the signal quality for each channel or for all channels is obtained. Can be.

Further, according to the signal wave amplifying system of the third aspect of the present invention, (1) a branching means for splitting the signal wave into two, and (2) a branching means, before or after the amplifying means for amplifying the signal wave. The first signal wave output from the first as an input wave
Alternatively, since the signal quality detecting device according to the second aspect of the present invention is used, even if the signal waves before and after the amplification are the signal waves of a plurality of channels in which the wavelength is multiplexed, the signal quality for each channel or for all the channels can be obtained. In addition, if necessary, the amplification factor of the amplifying means can be changed according to the signal quality.

Furthermore, according to the signal wave amplifying system of the fourth aspect of the present invention, (1) a branching means for splitting a signal wave into two, respectively, before and after an amplifying means for amplifying a signal wave; Since the signal quality detecting device according to the first or second aspect of the present invention uses one of the signal waves output from each of the branching means as an input wave, the signal wave before and after amplification is a wavelength-multiplexed signal wave of a plurality of channels. Even so, the signal quality for each channel or for all channels can be obtained, and if necessary, the amplification factor of the amplifying means can be changed according to the signal quality.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a first embodiment.

FIG. 2 is a diagram illustrating polarization planes of signal light and ASE light in the first embodiment.

FIG. 3 is a diagram illustrating the power of light detected by a photodiode when the detection light is on the y-axis in the first embodiment.

FIG. 4 is a diagram showing the power of light detected by a photodiode when the detection light is on the x-axis in the first embodiment.

FIG. 5 is a block diagram illustrating a configuration of a second embodiment.

FIG. 6 is a block diagram illustrating a configuration of a third embodiment.

FIG. 7 is a block diagram illustrating a configuration of a fourth embodiment.

FIG. 8 is a block diagram showing a configuration of a fifth embodiment.

FIG. 9 is an image diagram showing a spectrum of a multiplexed signal light amplified by an amplifier 11 according to a fifth embodiment.

FIG. 10 shows A / D converters 16-1 to 16-1 according to a fifth embodiment.
FIG. 6 is an image diagram showing a relationship between an output voltage to 6- (2n + 1) and an output port number.

FIG. 11 is a block diagram showing a configuration of a sixth embodiment.

FIG. 12 is a block diagram illustrating a configuration of a seventh embodiment.

[Description of Signs] 1, 11: Optical amplifier, 2, 12: Optical coupler, 3, 3A, 13, 13A: Wavelength separation filter, 4, 18: Optical switch, 5: Automatic polarization plane controller, 6, 6-1 6- (n + α): Ramipole, 6A: Polarization separation prism, 7, 7P, 7S, 7-1 to 7- (n + α), 14-1
14- (n + 1 + α)... Photodiode, 8, 8P, 8S, 8-1 to 8- (n + α), 15-1
15- (n + 1 + α): resistance, 9, 9P, 9S, 9-1 to 9- (n + α), 16-1 to
16- (n + 1 + α): A / D converter, 10, 17: CPU.

Claims (13)

[Claims] 1. A signal quality detection device for detecting the quality of a signal wave in an input wave having a polarized signal wave and a non-polarized noise wave, wherein a signal wave wavelength for extracting a wavelength component of the signal wave from the input wave Component extraction means, From the signal wave wavelength component wave extracted by the signal wave wavelength component extraction means, utilizing the difference between the polarization characteristics of the signal wave and the noise wave,
A signal quality detecting device comprising: signal quality estimating means for estimating a signal quality by estimating a signal wave power and a noise wave power. 2. The signal quality estimating unit includes: a polarization plane rotating unit configured to rotate a polarization plane of the signal wave wavelength component wave extracted by the signal wave wavelength component extracting unit; and a signal wave rotated by the polarization plane rotating unit. For a wavelength component wave, a polarization plane component separation unit that separates one or a plurality of polarization plane components in a predetermined direction, and a conversion unit that converts the power of the polarization plane component separated from the polarization plane component separation unit into a current or voltage signal. The signal quality detecting device according to claim 1, further comprising: a signal quality estimating unit that obtains a desired signal quality from a current or voltage signal from the conversion unit. 3. The input wave, in which signal waves of a plurality of channels having different wavelengths are multiplexed, wherein the signal wave wavelength component extracting means extracts a signal wave wavelength component wave for each channel. 3. The signal quality detecting device according to claim 1, wherein the quality estimating unit performs a quality estimating process for each signal wave of each channel. 4. The input wave, wherein signal waves of a plurality of channels having different wavelengths are multiplexed, wherein the signal wave wavelength component extracting means extracts a signal wave wavelength component wave for each channel. The quality estimating means includes: a polarization plane rotating unit provided before the signal wave wavelength component extracting means for rotating the polarization plane of the input wave; and a signal wave wavelength of each channel extracted by the signal wave wavelength component extracting means. A switch unit for selecting and outputting one signal wave wavelength component wave among the component waves; and for each channel, separating one or a plurality of polarization plane components in a predetermined direction from the component waves from the switch unit. A plurality of polarization plane separation units, a plurality of conversion units for each channel, which converts the power of the polarization plane component separated by the corresponding polarization plane separation unit into a current or voltage signal, and a current or a current from each of the conversion units. Voltage signal From the signal quality detector according to claim 1, characterized in that it comprises a desired signal the signal quality estimation unit for obtaining a quality for the signal wave of each channel. 5. A signal quality detecting device for detecting the quality of a signal wave in an input wave having a polarized signal wave and a non-polarized noise wave, comprising: a first component having the same wavelength as the signal wave from the input wave. Component wave extracting means for extracting a wave and a second component wave near the wavelength of the signal wave; and estimating the power of the noise wave in the wavelength component of the signal wave from the second component wave extracted by the component wave extracting means. And a signal quality estimating means for estimating the power of the signal wave from at least the first component wave to obtain the signal quality. 6. The input wave, in which signal waves of a plurality of channels having different wavelengths are multiplexed, wherein the component wave extracting means extracts a first component wave and a second component wave for each channel. Wherein the signal quality estimating means comprises: a first component wave and a second component wave for each channel extracted by the component wave extracting means,
The signal quality detection device according to claim 5, wherein signal quality is obtained for each channel. 7. The signal quality estimating means includes first and second signals for each channel extracted by the component wave extracting means.
7. The signal quality detecting device according to claim 6, further comprising a switch unit for selecting a component wave of any one of the component waves, and obtaining a signal quality of each channel in a time division manner. . 8. The signal quality detecting device according to claim 1, wherein the signal wave is an optical signal wave. 9. A signal wave amplifying system provided with amplifying means for amplifying a signal wave, a branching means for splitting a signal wave into two at a stage before or after the amplifying means, and one signal output from the branching means. A signal wave amplification system comprising: the signal quality detection device according to any one of claims 1 to 8, wherein the wave is an input wave. 10. A signal wave amplifying system comprising amplifying means for amplifying a signal wave, a branching means for splitting a signal wave into two at a stage before and after the amplifying means, and a signal output from each of the branching means. A signal wave amplification system comprising: the signal quality detection device according to claim 1, wherein the signal wave is used as an input wave. 11. A signal quality estimating means of a signal quality detecting device provided at a preceding stage of said amplifying means and a signal quality estimating means of a signal quality detecting device provided at a subsequent stage of said amplifying means are common. 11. The signal wave amplifying system according to claim 10, wherein a signal quality requiring information on signal waves before and after the amplifying means is detected. 12. The signal wave amplification system according to claim 9, further comprising an amplification factor adjusting unit that adjusts an amplification factor of the amplification unit based on the detected quality result. 13. The quality result for the gain adjusting means to adjust the gain of the amplifying means is a signal-to-noise ratio, a noise figure, or the power of the amplified signal wave. 13. The signal wave amplification system according to claim 12.