JP2001069082A - Optical wavelength multiplex network system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the error rate of main signals owing to the modulation of monitor signals by providing an optical signal multiplexer having comb shape transmission areas arranged in equal frequency interval and respectively and individually allocating the main signals and the monitor signals to the transmission areas. SOLUTION: The multiplexing of the main signals λ1-λ3 from a succeeding node with the monitor signals λ#1-λ#3 is inputted to a demultiplexer 2 and they are demultiplexed into multiplex signals λ1+λ#1, λ2+λ#2 and λ3+λ#3 and transferred to an optical switch part 3. The demultiplexer 2 is constituted of a Fabry-Perot filter provided with a comb shape characteristic for repeating the transmission areas by equal frequency interval or the like and the main signals λand the monitor signals λ# are set to positions aligned to prescribed interval ITU grids. An optical switch part 3 transmits the prescribed multiplex signal to the multiplexer 4 in accordance with a change-over signal from a controller part 8, synthesizes it with the multiplex signal from another wave length pass and transfers it to the succeeding node with an optical multiplex link. Thus, the error rate of the signal is reduced, the main signal and the monitor signal is made to be one group and, then, transmission is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wavelength division multiplexing network system for monitoring a wavelength path established in a network by a wavelength path monitor signal.

[0002]

2. Description of the Related Art In an optical wavelength division multiplexing network, a large number of wavelength paths passing through a large number of nodes are constructed. Therefore, in order to normally operate a wavelength path, a monitoring system for monitoring a node (relay station or the like) serving as a connection point of the wavelength path and an optical multiplex link (optical fiber) connecting the nodes is indispensable. It is becoming. In the monitoring system, a monitoring signal is transmitted between the ends of the wavelength path for each wavelength path, that is, from the front end to the rear end. A multiplexing method of modulating a main signal transmitted on a wavelength path with a monitoring signal is adopted as a transmission method of the monitoring signal.

[0003]

However, the above-mentioned prior art has the following problems to be solved.
The problem to be solved remains that the error rate of the main signal increases as the modulation rate of the monitor signal with respect to the main signal increases. The details are reported in, for example, [Prototype Production of Optical Path Monitoring Circuit Using Pilot Tone, Fujitsu Laboratories Ltd., 1998 IEICE Communication Society Conference].

[0004]

The present invention employs the following structure to solve the above problems. <Configuration 1> A plurality of nodes are connected via an optical multiplex link. The optical multiplex link between the nodes includes a main signal for constructing a wavelength path using a light wave of a predetermined wavelength, and the predetermined wavelength. The monitoring signals by light waves having different wavelengths are multiplexed, and the node includes an optical signal multiplexer having a comb-like transmission region arranged at equal frequency intervals, and the main signal includes the comb-like transmission region. Wherein the monitoring signal is allocated to another one of the comb-shaped transmission regions.

<Structure 2> An optical wavelength division multiplexing network system according to Structure 1, wherein the comb-shaped transmission area is matched with an ITU grid.

<Structure 3> In the optical wavelength division multiplexing network system according to the structure 1 or 2, a part of the output of the optical signal multiplexer having a comb-like transmission region arranged at the same frequency interval is received. An optical monitor for branching and outputting, an optical filter for receiving the output of the optical monitor and transmitting only the monitoring signal, and an O / E (photoelectric converter) for photoelectrically converting the transmitted light of the optical filter and outputting the converted light. ), Wherein the node is controlled based on the output of the O / E (photoelectric converter).

<Configuration 4> In the optical wavelength division multiplexing network system according to configuration 3, the frame of the supervisory signal is set without straddling the frame of the main signal, and a part of the supervisory signal includes the wavelength path of the wavelength path. An optical wavelength division multiplexing network system comprising switching information.

<Structure 5> In the optical wavelength-division multiplexing network system according to structure 1 or 2, the wavelength of the optical multiplex link between the nodes is different from any wavelength of the main signal and the monitor signal, and The OTS signal allocated to the non-transmissive area of the signal combiner is further multiplexed, and the node accepts the output of another node preceding the node and transfers the output from the other node preceding this node. An OTS separation unit that extracts the OTS signal that is transmitted and transmits the main signal and the monitoring signal to the optical signal multiplexing;
The output of the above node is transferred to another following node O
An optical wavelength division multiplexing network system comprising an OTS adding unit for multiplexing a TS signal and transferring the multiplexed TS signal to another subsequent node.

<Structure 6> In the optical wavelength-division multiplexing network system according to the structure 1 or 2, the optical multiplex link between the nodes is different from any wavelength of the main signal and the monitor signal, and the optical The OTS signal allocated to the non-transmissive area of the signal combiner is further multiplexed, and the node accepts the output of another node preceding the node, and receives the monitor signal and the preceding signal from this output. Extract OTS signals transferred from other nodes,
An OTS demultiplexing unit that transmits the main signal to the optical signal multiplexer; a signal addition unit that multiplexes the monitoring signal with the main signal output by the optical switch that performs wavelength path switching; OTS for multiplexing the OTS signal to be transferred to the following subsequent node and transferring to the following subsequent node
An optical wavelength division multiplexing network system comprising an assigning unit.

<Structure 7> In the optical wavelength division multiplexing network system according to structure 6, the monitor signal and the OTS signal multiplexed on the optical multiplex link between the nodes are:
A lightwave that is electrically multiplexed and further subjected to E / O (Electro-Optical Conversion); a monitoring signal modulation unit that electrically multiplexes the monitoring signal and the OTS signal; An optical wavelength division multiplexing network system comprising an electrical signal separating unit for separating the monitoring signal and the OTS signal.

<Structure of Embodiment 1> FIG. 1 is a block diagram of an optical node provided in an optical wavelength division multiplexing network system of Embodiment 1. Before describing the optical node, an overview of the entire system will be described with reference to the drawings. FIG. 2 is a schematic explanatory diagram of an optical wavelength division multiplexing network system according to the present invention. As shown in FIG. 2, the optical wavelength division multiplexing network system includes, as an example, a node A, a node B, a node C,
An optical multiplex link 1 (1-1 to 1-16 in the figure) and an operation center 21 are provided.

Each of the nodes A, B and C represents a relay station as an example. Each node is
Inside the optical switch unit 3 (3A to 3C in the figure), the monitor signal multiplexing unit 6 (6A to 6C in the figure), and the monitor signal separating unit 7
(7A to 7C on the figure) and the control device unit 8 (8A to 8 on the figure)
C). These components will be described later in detail with reference to FIG. The optical multiplex link 1 (1-1 to 1-16 in the figure) is an optical fiber connecting each node. The operation center 21 controls the entire optical wavelength division multiplexing network system.

On the optical wavelength division multiplexing network system described above, a number of wavelength paths for transmitting a main signal obtained by converting information such as audio and video into digital data are constructed.
Here, as an example, it is assumed that a wavelength path X from the node A to the node C through the node B and a wavelength path Y from the node A to the node C are constructed. At this time, the wavelength path X
In order to achieve normal operation of X, the X monitor signal 22
The signal is wavelength-multiplexed with the main signal X and transmitted.

Similarly, the Y monitor signal 23 is wavelength-multiplexed with the main signal Y and transmitted to the wavelength path Y for normal operation of the wavelength path Y. The present invention is characterized by the method of multiplexing the main signal and the supervisory signal. Hereinafter, an optical node (here, a repeater) that transmits and receives the monitoring signal using this multiplexing method.
Will be described with reference to FIG. The following description is limited to the node A as an example.

As shown in FIG. 1, the optical node provided in the optical wavelength division multiplexing network system of the embodiment 1 is an optical multiplex link 1 (1
-1, 1-2, 1-3, 1-4, 1-5, 1-6);
Demultiplexer 2 (2-1, 2-2, 2-3), optical switch unit 3, multiplexer 4 (4-1, 4-2, 4-3), and supervisory signal multiplexing unit 6 ( 6-1, 6-2, 6-3), a monitoring signal separation unit 7 (7-1, 7-2, 7-3), and a control device unit 8.

Optical multiplex link 1 (1-1, 1-2, 1-
3, 1-4, 1-5, and 1-6) are optical fibers that connect the nodes as described above. This is a portion where an optical signal in which a number of wavelength paths are mixed and transmitted is transmitted. The demultiplexer 2 (2-1, 2-2, 2-3) is connected to the optical multiplex link 1
From the main signals λ1 to λ3 and the monitoring signals λ♯1 to λ♯3,
This is an optical filter that receives the multiplexed optical signal and splits the signal for each wavelength. These six waves are examples and are not the wave numbers to which the present invention is limited. The duplexer 2 (2-1, 2-2, 2-
3) is a Fabry-Perot filter 2-1-1 that transmits the main signal λ1 and the monitoring signal λ♯1 while multiplexing them.
A Fabry-Perot filter 2-1-2 for transmitting the main signal λ2 and the monitoring signal λ♯2 while multiplexing them, and a main signal λ
3 and a supervisory signal λ♯3.
The function of the duplexer 2 will be described below with reference to the drawings.

FIG. 3 is a diagram for explaining the function of the duplexer.
(A) is an explanatory view of the principle of a duplexer. (B) is a figure which shows the transmission characteristic of a duplexer. (C) is a partial enlarged view of (b).

The duplexer 2 is formed using a Fabry-Perot filter as an example. (A) The Fabry-Perot filter has a reflection surface 25 and a reflection surface 26, and transmits only an optical signal having a frequency at which a standing wave of the optical signal is generated between the two reflection surfaces in a spectrum shape. Hereinafter, the present invention is limited to the Fabry-Perot filter, but the present invention is not limited to the Fabry-Perot filter. That is, another filter may be used as long as the filter has a comb-shaped characteristic that repeats the transmission region at equal frequency intervals.

A curve 27 indicated by a dotted line in (b) shows the frequency spectrum of the emitted light of the laser diode with the horizontal axis (frequency axis) enlarged with the center frequency f0 as the center. A straight line 28 extending in the vertical axis direction shows the spectrum of the transmitted light transmitted through the Fabry-Perot filter. That is, when the optical signal shown by the curve 27 is input to the duplexer 2, from the output thereof, f + 1, f-1, and f + are set around f0 according to the transmission characteristics of the Fabry-Perot filter.
2, f-2, f + 3, f-3,... Are transmitted in the form of spectrum.

FIG. 3C is an enlarged view of a portion A in FIG. In the figure, filters 29, 30, and 31 indicate the transmission ranges of the Fabry-Perot filters near frequencies f-1, f0, and f + 1, respectively. or,
A group of straight lines parallel to the vertical axis is the spectrum of the optical signal defined in the ITU grid. Therefore, only the transmitted light transmitted through the filters 29, 30, and 31 is output from the duplexer.

Next, the configuration of the duplexer 2 using the Fabry-Perot filter described above will be described with reference to an example. FIG. 4 is an explanatory diagram of frequency assignment of a main signal and a monitoring signal in the specific example 1. (A)
The ITU grid at 0.1 THz intervals is shown.
(B) shows the frequency allocation of the main signal. (C)
Indicates the frequency assignment of the monitoring signal. (D),
(E) and (f) show the filter characteristics of the Fabry-Perot filter, respectively. The horizontal axes in (a) to (f) are all represented by the same frequency axis. However, the frequency (THz) decreases as going rightward in the figure.

(A) More specifically, the system of the first embodiment uses an optical signal according to the ITU grid at intervals of 0.1 THz as an example. As shown in (b), as an example, the main signals λ1, λ2, λ3 are set to 194.0 THz, 193.
9 THz and 193.8 THz are set.

As shown in FIG. 3C, as an example, the monitoring signal λ
♯1, λ♯2, λ♯3 are set to 196.5 THz, 19
It is set to 6.4 THz and 196.3 THz. Here, λ♯1 (THz) −λ1 (THz) = λ♯2 (TH
z) −λ2 (THz) = λ♯3 (THz) −λ3 (TH
z) = 2.5 (THz). As shown in (d), the Fabry-Perot filter 2-1-3 sets the center frequency of the adjacent transmission band to the frequency 19 of the main signal λ3.
3.8 THz and the frequency of the monitoring signal λ♯3 196.3 TH
It is set at a position that matches z.

As shown in (e), the Fabry-Perot filter 2-1-2 matches the center frequency of the adjacent transmission band with the frequency of 193.9 THz of the main signal λ2 and the frequency of 196.4 THz of the monitor signal λ♯3. Is set to the position that was set. As shown in (f), Fabry-Perot filter 2-1
-1 indicates the center frequency of the adjacent transmission band as the main signal λ2
193.9 THz and the frequency 1 of the monitoring signal λ♯3
The position is set to coincide with 96.4 THz.

Now that the description of the duplexer 2 has been completed, returning to FIG. 1 again, the description of the configuration of the optical node provided in the specific example will be continued. The optical switch unit 3 controls the multiplexing signal (main signal λ1 + monitoring signal λ♯1) and the multiplexed signal (main signal λ2 + monitoring signal λ♯) by the duplexer 2 under the control of the control unit 8.
2) and an optical switch that receives an optical signal demultiplexed into a multiplexed signal (main signal λ2 + monitoring signal λ♯2) and switches the wavelength path.

The multiplexer 4 (4-1, 4-2, 4-3)
A multiplexed signal (main signal λ + monitoring signal λ♯)
1), a multiplexed signal (main signal λ2 + monitoring signal λ♯2),
This is a part that receives a lightwave demultiplexed into a multiplexed signal (main signal λ2 + monitoring signal λ♯2) and multiplexes it again into a six-wave multiplexed signal. This is also a part for transmitting the six-wave multiplexed signal to the adjacent node B (FIG. 2) via the optical multiplex link 1-2. As an example, a three-input one-output optical coupler is used.

The monitoring signal multiplexing unit 6 (6-1, 6-2, 6-
3) receives the intra-station input of the optical signal from the intra-station line, converts it into a main signal (λ1 to λ3) of a predetermined frequency, and further multiplexes a predetermined monitoring signal (λ♯1 to λ♯3). This is a part to be sent to the optical switch unit 3. Here, the monitoring signal multiplexing unit 6
1 multiplexes the main signal λ1 and the monitoring signal λ♯1, the monitoring signal multiplexing unit 6-2 multiplexes the main signal λ2 and the monitoring signal λ♯2, and the monitoring signal multiplexing unit 6-3 outputs Signal λ3 and monitor signal λ
This is the portion that combines # 3.

The monitor signal multiplexing unit 6 (6-1, 6-2, 6-
3) has O / E + E / O.9 and E / O.1 inside
0 and a multiplexer 11. The O / E + E / O.9 receives an optical signal input from the intra-station wiring 15 and temporarily converts the signal into an optical signal, and further converts a main signal (λ1 to λ3) having a predetermined frequency.
This is the part that converts the light to light and outputs it.

The E / O · 10 receives a control signal of an electric signal from the control unit 8, converts the signal into a predetermined monitor signal (λ♯1 to λ♯3), and outputs the monitor signal. is there.
The multiplexer 11 receives a main signal (λ1 to λ3) of a predetermined frequency from O / E + E / O · 9 and a predetermined monitoring signal (λ♯1 to λ♯3) from the E / O · 10, respectively. This is a part that multiplexes and sends out to the optical switch unit 3. As an example, a two-input one-output optical coupler is used.

The monitoring signal separation unit 7 (7-1, 7-2, 7-
3) receives the wavelength multiplexed signal from the optical switch unit 3 and separates the wavelength multiplexed signal into an intra-station output of a predetermined frequency which is an optical signal and a control signal which is an electric signal.
1, 16-2, 16-3) and a control signal to the control unit 8. Here, the monitoring signal separation unit 7
-1 receives the multiplexed signal (main signal λ1 + monitoring signal λ♯1) and separates the main signal λ1 from the monitoring signal λ♯1, and the monitoring signal separating unit 7-2 outputs the multiplexed signal (main signal λ1 + monitoring signal λ♯1).
# 2) and separates it into a main signal λ2 and a supervisory signal λ♯2. The supervisory signal separator 7-3 outputs the multiplexed signal (main signal λ3
+ Monitoring signal λ♯3) and is separated into a main signal λ3 and a monitoring signal λ♯3.

The monitoring signal separation unit 7 (7-1, 7-2, 7-
3) includes a duplexer 12 therein and O / E + E / O · 1
3 and O / E · 14. The splitter 12 receives the multiplexed signal from the optical switch unit 3 and receives the main signals (λ1 to λ3).
And O / E + E / O · 13 and O / E · 14, respectively, which are separated into monitoring signals (λ♯1 to λ♯3). As an example, the above Fabry-Perot filter and further,
In order to split λ1 and λ 例 え ば 1, for example, a multilayer filter or the like is added.

The O / E + E / O.13 receives the main signals (λ1 to λ3) from the duplexer 12, temporarily converts the signals into optical signals, and further converts the signals into optical signals in the office at a predetermined frequency. This is the part to do. The O / E 14 receives the monitoring signals (λ♯1 to λ♯3) from the duplexer 12, converts the optical signals into control signals as electric signals, and sends the signals to the control unit 8. It is. The control unit 8 transmits the operation information of the optical wavelength division multiplexing network system such as network monitoring information and connection information of the optical switch unit 3 to the operation center 2.
This is the part that communicates with 1.

<Operation of Embodiment 1> Next, FIGS. 2, 3 and 4
The operation of the optical wavelength division multiplexing network system of the first embodiment will be described with reference to FIG. The wavelength path X (FIG. 2) will be described as an example. The wavelength path X (FIG. 2) includes the node A, the optical multiplex link 1-1, and the node B.
And the optical multiplex link 1-10 and the node C are connected. Here, node A, node B, and node C
Since they have exactly the same configuration, they will all be described with reference to FIG.

The wavelength path A transmitter 32 of the node A (same as in FIG. 1) serves as an end (start point) of the wavelength path X, and converts, for example, voice into an optical signal and inputs it into the monitoring signal multiplexing unit 6-6. Send to 1. O / E + of monitoring signal multiplexing section 6-1
The E / O 9 receives the intra-station input, converts it into a main signal λ1, and transfers it to the multiplexer 11. At this time, the control unit 8
Sends a control signal to the monitor signal multiplexing unit 6-1.

The E / O · 10 of the monitor signal multiplexing section 6-1 is
The control signal is received, converted into a monitor signal λ♯1, and transferred to the multiplexer 11. The multiplexer 11 receives the main signal λ1 and the monitoring signal λ♯1, multiplexes the multiplexed signal (main signal λ1 + monitoring signal λ♯1), and transfers the multiplexed signal to the optical switch unit 3. The optical switch unit 3 simultaneously receives a control signal (switching information) from the control unit 8 and transfers a multiplexed signal (main signal λ1 + monitoring signal λ 信号 1) to the multiplexer 4-1 according to the switching information.

At this time, the multiplexer 4-1 receives the multiplexed signal (signal λ2 + monitoring signal λ♯2) and the multiplexed signal (signal λ3 + monitoring signal λ♯) from another wavelength path different from the wavelength path X.
3) is accepted. The multiplexer 4-1 includes a multiplexed signal (signal λ1 + monitoring signal λ♯1), a multiplexed signal (signal λ2 + monitoring signal λ♯2), and a multiplexed signal (signal λ2 + monitoring signal λ♯).
2) is multiplexed and transferred to the optical multiplex link 1-1.

The optical multiplex link 1-1 transfers the six-wave combined optical signal to the node B (FIG. 2). The operation of the node B (FIG. 2) will be described again with reference to FIG.
The demultiplexer 2-2 (FIG. 1) of the node B (FIG. 2) receives the 6-multiplexed optical multiplexed signal. Demultiplexer 2-2 (Fig. 1)
Converts the six-wave combined optical signal into a multiplexed signal (signal λ1
+ Monitoring signal λ♯1), a multiplexed signal (signal λ2 + monitoring signal λ♯2), and a multiplexed signal (signal λ3 + monitoring signal λ♯3), which are transferred to the optical switch unit 3.

The optical switch unit 3 receives a multiplexed signal (signal λ1 +
Monitoring signal λ♯1) and a multiplexed signal (signal λ2 + monitoring signal λ)
# 2) and a multiplexed signal (signal λ2 + monitoring signal λ♯2) and a control signal (switching signal) from the control unit 8 at the same time as receiving the multiplexed signal (main signal λ1 + monitoring signal λ♯1) according to the switching information. ) To the multiplexer 4-2.

At this time, the multiplexer 4-2 outputs the multiplexed signal (signal λ2 + monitoring signal λ♯2) and the multiplexed signal (signal λ3 + monitoring signal λ♯) from another wavelength path different from the wavelength path X.
3) is accepted. The multiplexer 4-2 includes a multiplexed signal (signal λ1 + monitoring signal λ♯1), a multiplexed signal (signal λ2 + monitoring signal λ♯2), and a multiplexed signal (signal λ3 + monitoring signal λ♯).
3) is multiplexed and transferred to the optical multiplex link 1-1 (corresponding to the optical multiplex link 1-10 in FIG. 2).

The optical multiplex link 1-1 transfers the six-wave combined optical signal to the node C (FIG. 2). The operation of the node C (FIG. 2) will be described again with reference to FIG.
The demultiplexer 2-2 (FIG. 1) of the node C (FIG. 2) receives the six-wave combined optical signal. The demultiplexer 2-2 (FIG. 1)
The six combined optical signals are combined into a multiplexed signal (signal λ1 + monitoring signal λ♯1) and a multiplexed signal (signal λ2 + monitoring signal λ♯).
2) and a multiplexed signal (signal λ2 + monitoring signal λ♯2) and transferred to the optical switch unit 3.

The optical switch unit 3 receives a multiplexed signal (signal λ1 +
Monitoring signal λ♯1) and a multiplexed signal (signal λ2 + monitoring signal λ)
# 2) and a multiplexed signal (signal λ3 + monitoring signal λ♯3) and a control signal (switching information) from the control unit 8 at the same time, and a multiplexed signal (main signal λ1 + monitoring signal λ♯1) according to the switching information. ) Is transferred to the monitoring signal separation unit 7-1. At this time, the multiplexed signal (signal λ2 + monitoring signal λ♯)
2) and the multiplexed signal (signal λ3 + monitoring signal λ♯3) are transferred along the wavelength paths already established according to the switching information.

The duplexer 12 of the supervisory signal separating section 7-1 receives the multiplexed signal (main signal λ1 + monitoring signal λ♯1), demultiplexes the multiplexed signal into the main signal λ1 and the supervisory signal λ♯1, and demultiplexes the main signal λ1. O
/E+E/O.13 to the monitor signal λ♯1
Transfer to O / E + E / O · 13 converts the main signal λ1 into an in-station output of a predetermined wavelength and is the end of the wavelength path.
The data is transferred to the wavelength path A receiver 33. The O / E 14 optically / electrically converts the monitoring signal λ♯1 and sends it to the control unit 8 as a control signal of an electric signal. This is the end of the description of the operation of the optical wavelength division multiplexing network system of the first embodiment.

In the above description, the main signal 3
Although the description is limited to three waves and three monitoring signals, the number of multiplexes is arbitrarily set according to the scale of the system. Also, the optical signal has been described as being limited to the ITU grid at intervals of 0.1 THz, but this value can also be set arbitrarily according to the specifications of the system.

Λ♯1 (THz) −λ1 (THz) =
λ♯2 (THz) −λ2 (THz) = λ♯3 (THz)
Although the description has been made by limiting to −λ3 (THz) = 2.5 (THz), this value can also be arbitrarily set according to the specifications of the system. Further, λ1, λ2, λ3 or λ♯
Although 1, λ♯2 and λ♯3 are set in adjacent ITU grids, these values can also be set arbitrarily according to the specifications of the system.

<Effect of Specific Example 1> As described above,
For example, a filter having a comb-shaped transmission characteristic at a constant frequency interval such as a Fabry-Perot filter is provided, and the following effects are obtained by allocating the frequencies of the light source spectrum of the main signal and the monitoring signal to the transmission region. 1. The main signal and the monitoring signal can be transmitted as one set. 2. A single set of main signal and monitoring signal can be separated while being multiplexed by one filter.

<Structure of Embodiment 2> FIG. 5 is a block diagram of an optical node provided in the optical wavelength division multiplexing network system of Embodiment 2. As shown in FIG. 5, the optical node provided in the optical wavelength division multiplexing network system of the specific example 2 has the optical multiplex link 1
(1-1, 1-2, 1-3, 1-4, 1-5, 1-6)
, A duplexer 2 (2-1, 2-2, 2-3), an optical switch unit 3, a multiplexer 4 (4-1, 4-2, 4-3), and a monitor signal multiplexing unit. 6 (6-1, 6-2, 6-3), monitor signal separation unit 7 (7-1, 7-2, 7-3), optical monitor unit 35, optical filter 36, O / E・ It is equipped with 37.

The optical monitor unit 35 is connected to the duplexer 2 (2-1, 2).
-2, 2-3), the main signal (λ1, λ2, λ3) and the monitor signal (λ♯1, λ♯2, λ♯3) are received, part of which is separated and transferred to the optical filter 36. And a portion for transferring most of the remaining optical signals to the optical switch section 3. As an example, a semipermeable membrane branching device or the like is used.

The optical filter 36 receives the main signals (λ1, λ2, λ3) from the optical monitor 35 and the monitoring signals (λ♯1, λ♯).
2, λ♯3) and receive a part of the monitoring signal (λ♯1,
λ♯2 and λ♯3) are separated into three waves,
This is a part to be transferred to E.37. An optical filter having a transmission wavelength λ♯1, an optical filter having a transmission wavelength λ♯2, and a transmission wavelength λ
It is composed of # 3 optical filters. As an example, a multilayer filter or the like is used.

The O / E · 37 outputs the monitoring signals λ {1, λ}
2. Accepting λ♯3 and converting the control signal, which is an electrical signal, to light /
This is a part for converting the electric power and transferring it to the control unit 8. All the other components are the same as those in the first embodiment, and the description is omitted.

<Operation of Embodiment 2> The optical wavelength division multiplexing network system according to Embodiment 2 is most suitable for a system using fixed-length frames or packets for both the main signal and the supervisory signal. Hereinafter, an example of the signal format used in the specific example 2 will be described.

FIG. 6 is an explanatory diagram of the signal format of the second embodiment. (A) shows a monitoring signal and (b) shows a main signal. The horizontal axis represents the time axis common to (a) and (b). Note that the monitoring signal and the main signal do not need to be completely synchronized. Main signal data (for example, data 2 in the figure)
It is sufficient that the monitoring signal 2 falls within the range of. That is, it is sufficient that the monitoring signal does not extend over the two main signals.

As shown in (a), switch switching information is added to a part of the monitoring signal (monitoring 2 in the figure). In this switch switching information, wavelength path switching information in the optical switch unit 3 (FIG. 5) is written. Dummy data is written in data 2 of the main signal. The description of an example of the signal format employed in the specific example 2 has been completed above. Therefore, returning to FIG. 5 again, the operation of the specific example 2 will be described.

Only the differences from the operation of the first embodiment will be described. From the optical multiplex link 1-5, the demultiplexer 2-2 receives the six-wave combined optical signal. The duplexer 2-2 has the 6
The multiplexed optical signal is divided into a multiplexed signal (signal λ1 + monitoring signal λ♯1) and a multiplexed signal (signal λ2 + monitoring signal λ♯2).
Multiplexed into a multiplexed signal (signal λ3 + monitoring signal λ 分 3) and transferred to the optical monitor unit 35.

The optical monitor 35 receives the main signals (λ1, λ2, λ3) from the demultiplexer 2-2 and the monitoring signals (λ {1, λ}).
2, λ♯3), and a part thereof is separated and transferred to the optical filter 36, and most of the remaining signals are transferred to the optical switch unit 3. The optical filter 36 outputs the main signals (λ1, λ2, λ3) from the optical monitor unit 35 and the monitoring signals (λ {1, λ}).
2, λ♯3) and receive a part of the monitoring signal (λ♯1,
λ♯2, λ♯3) are separated into three waves and transmitted, and O /
Transfer to E37.

The O / E · 37 outputs the monitoring signals λ {1, λ}.
2. Accepting λ♯3 and converting the control signal, which is an electrical signal, to light /
The electric power is converted and transferred to the control unit 8. The control unit 8
When the switch switching information is detected in the received control signal (assuming that the switch signal has been written in the monitor signal of the monitor signal λ 、 1 and the monitor 2), the switch control information is detected based on the switch switch information. The control signal (switching information) is sent to the optical switch unit 3.

When receiving the control signal (switching information), the optical switch unit 3 receives the multiplexed signal (signal λ1 + monitoring signal λ).
(1) is transferred to the multiplexer 4-2 according to the control information (switching information). At this time, the multiplexed signal (signal λ2 + monitoring signal λ♯)
2) and the multiplexed signal (signal λ3 + monitoring signal λ♯3) are respectively transmitted along the wavelength paths already established. The other operations are exactly the same as those of the first embodiment, and the description is omitted.

<Effect of Specific Example 2> As described above,
An optical monitor, an optical filter, and an O / E
The following effects are obtained by adding. 1. The switching of the optical switch unit can be performed based on information from the monitoring signal. 2. Further, by writing dummy data (invalid data) in a main signal frame (data 2 in FIG. 6) that matches on the time axis with a frame of the monitoring signal (monitoring 2 in FIG. 6) in which the switch switching information is written. It is possible to perform instantaneous interruption switching without interruption of the main signal in the middle.

<Structure of Embodiment 3> FIG. 7 is a block diagram of an optical node provided in the optical wavelength division multiplexing network system of Embodiment 3. As shown in FIG. 7, the optical node provided in the optical wavelength division multiplexing network system of the specific example 3 is an optical multiplex link 1
(1-1, 1-2, 1-3, 1-4, 1-5, 1-6)
, A duplexer 2 (2-1, 2-2, 2-3), an optical switch unit 3, a multiplexer 4 (4-1, 4-2, 4-3), and a monitor signal multiplexing unit. 6 (6-1, 6-2, 6-3), the monitoring signal separation unit 7 (7-1, 7-2, 7-3), and the OTS separation unit 41 (41-1, 41-2, 41). -3), the OTS adding unit 42 (42-1, 42-2, 42-3), and the O / E
43 (43-1, 43-2, 43-3) and E / O.4
4 (44-1, 44-2, 44-3).

The OTS separation unit 41 multiplexes the OTS signal λ with the main signal from an adjacent node and transfers the multiplexed signal.
This is the part that separates *. Here, the OTS signal is, for example, a network monitoring signal communicated between adjacent nodes in order to normally operate the network on the optical transport section. As an example, OTS
By monitoring signal level fluctuations, it is possible to detect a failure or the like between adjacent nodes.

The principle of the OTS separation unit 41 will be described below with reference to the drawings. FIG. 8 is an explanatory diagram of frequency allocation of various signals in the specific example 3. A curve 27 indicated by a dotted line in FIG. 8 shows the frequency spectrum of the transmission light of the laser diode with the horizontal axis enlarged with the center frequency f0 as the center. A straight line 28 extending in the vertical axis direction shows the spectrum of the transmitted light transmitted through the Fabry-Perot filter. That is, when the optical signal shown by the curve 27 is input to the duplexer 2, from the output thereof, f + 1, f-1, and f are centered on f0 according to the transmission characteristics of the Fabry-Perot filter.
+2, f-2, f + 3, f-3,... Are transmitted in the form of spectrum.

The frequency range of the OTS signal λ * is assigned to fx or fy in the figure as an example. This frequency range fx,
The assignment requirements of fy are determined as follows. Requirement 1 The frequency ranges fx and fy do not match the transmission range of the Fabry-Perot filter as shown in the figure. Requirement 2 The frequency ranges fx and fy deviate from the vicinity of the frequency range fo of the main signal and the monitoring signal. As long as the requirements 1 and 2 are satisfied, different light sources may be used, for example, in the frequency range fz.

FIG. 9 is a block diagram of the OTS separation unit. As shown in FIG.
And a diffraction grating fiber 46. When the circulator 45 has, for example, three apertures A, B, and C as shown in the figure, the optical signal input to the aperture A is output to the aperture B, and the optical signal input from the aperture B is Opening C
This is a device that organizes traffic so that it is output to a device.

The diffraction grating fiber 46 is a special optical fiber in which a large number of portions having a large refractive index and a large number of portions having a small refractive index are formed in the core portion of the optical fiber in the form of a diffraction grating in the length direction at minute intervals and continuously repeated. It is called FBG.
In this specific example, the diffraction grating fiber 46 is connected to the opening B of the circulator 45, and the diffraction grating is set in the frequency range of the OTS signal λ *.

That is, the diffraction grating fiber 46
Is reflected by the diffraction grating and output from the aperture C. In the specific example 3, from the opening A to the OT
The output of the S separation unit 41 is received, the output of the diffraction grating fiber 46 connected to the aperture B is connected to the duplexer 2, and the aperture C is connected to the O / E 43. With the above, the OTS separation unit 41
7 has been completed, the description is returned to FIG. 7 again, and the description of the configuration of the specific example 3 is continued.

O / E · 43 (43-1, 43-2, 43
Reference numeral -3 denotes an optical / electrical converter that receives the OTS signal λ *, which is an optical signal, from the OTS separation unit 41, converts the OTS signal λ * into an electric signal, and transfers the OTS signal λ * to the control unit 8. E
The / O · 44 (44-1, 44-2, 44-3) receives the OTS signal λ *, which is an electric signal transmitted from the control device unit 8 to an adjacent node, converts it into an optical signal, and converts it into an optical signal. This is an electro / optical converter for transferring the data to an optical / optical converter 42.

The OTS adding section 42 (42-1, 42-2,
42-3) are E / O • 44 (44-1, 44-2, 4).
4-3), an OTS signal λ *, which is an optical signal, is received and a multiplex signal (signal λ1 + monitoring signal λ♯1), a multiplex signal (signal λ2 + monitoring signal λ 信号 2), and a multiplex signal (signal λ3 + monitoring signal λ♯3) ). Usually, an optical coupler or the like is used. Now that the description of the configuration of the specific example 3 has been completed, the operation of the specific example 3 will be described by limiting only the operation of separating and adding the OTS signal λ *. The other operations are exactly the same as those in the first embodiment, and the description is omitted.

<Operation of Specific Example 3> The premise of the description of the operation is determined as follows. Node B receiving OTS signal λ * transferred from node A (FIG. 2) to node B (FIG. 2)
Only the operation of FIG. 2 and the operation of node B (FIG. 2) transmitting the OTS signal transferred from node B (FIG. 2) to node C (FIG. 2) will be described using FIG. 7 (FIG. 7). (Assuming node B in FIG. 2). The operation of exchanging the OTS signal λ * between the other nodes is exactly the same, and the description is omitted.

First, the reception of the OTS signal λ * will be described. In FIG. 7, the OTS demultiplexing unit 41-2 outputs a multiplexed signal (main signal λ1 + monitoring signal λ♯) from the optical multiplexing link 1-5.
1) and an optical signal in which the OTS signal λ * transferred from the node A (FIG. 2) is multiplexed is accepted. The circulator 45 (FIG. 9) receives the multiplexed optical signal into the aperture A (FIG. 9).

Multiplex signal (main signal λ1 + monitoring signal λ♯1)
Are transmitted to the duplexer 2-2 through the aperture B (FIG. 9). The OTS signal is reflected in the diffraction grating fiber 46, returns to the aperture B, and is transmitted to the O / E 43-2 through the aperture C. The OTS signal λ * is optically / electrically converted by the O / E 43-2 and transferred to the control unit 8.

Next, transmission of the OTS signal λ * will be described. In FIG. 7, the control unit 8 performs the OT of the electric signal.
The S signal λ * is sent to the E / O 44-2. E / O ・ 4
In step 4-2, the OTS signal of the electric signal is electro-optically converted and transferred to the OTS providing unit 42-2. OTS providing unit 42-
2 multiplexes the OTS signal λ * of the optical signal with the multiplexed signal (main signal λ1 + monitoring signal λ♯1) received from the multiplexer 4-2 and transfers it to the node C (FIG. 2). Other operations are described in Example 1.
Since the operation is exactly the same as that of the above, the description is omitted.

In the above description, the OTS separation unit 41 is
Has been described using only the circulator 45 and the diffraction grating fiber 46, but the present invention is not limited to this. For example, a multiplexed signal (main signal λ1 + monitoring signal λ♯1), a multiplexed signal (main signal λ
2 + monitoring signal λ♯2) and a filter having a wide transmission band that transmits the multiplexed signal (main signal λ3 + monitoring signal λ♯3) collectively, and a filter having a narrow transmission band that transmits only the OTS signal λ *. It is also possible to configure.

<Effect of Specific Example 3> As described above,
The following effects are obtained by setting the transmission range of the OTS signal λ * in a frequency band different from the transmission range of the duplexer, and providing the OTS separation unit before the duplexer. 1. Even if the OTS separation unit does not completely separate the OTS signal λ *, the OTS signal component is composed of a multiplexed signal (main signal λ1 + monitoring signal λ♯1) and a multiplexed signal (main signal λ2 + monitoring signal λ♯2). ) And (main signal λ3 + monitoring signal λ)
It is not transferred to another node while being mixed in # 3). 2. The frequency range of the OTS signal λ * is multiplexed (main signal λ1
+ Monitoring signal λ♯1), multiplexed signal (main signal λ2 + monitoring signal λ♯2), and (main signal λ3 + monitoring signal λ♯3) can be assigned to a frequency range that cannot be used. Need not be reduced.

<Structure of Embodiment 4> FIG. 10 is a block diagram of an optical node provided in the optical wavelength division multiplexing network system of Embodiment 4. As shown in FIG. 10, the optical nodes provided in the optical wavelength multiplexing network system of the specific example 4 are the optical multiplexing links 1 (1-1, 1-7, 1-8, 1-9, 1-10, 1-
11), a demultiplexer 2 (2-1, 2-2, 2-3), an optical switch unit 3, and a multiplexer 4 (4-1, 4-2, 4-3).
And O / E + E / O.9 (9-1, 9-2, 9-3)
And O / E + E / O.13 (13-1, 13-2, 13
-3) and the OTS providing unit 42 (42-1, 42-2, 4
2-3) and E / O · 44 (44-1, 44-2, 44)
-3) and the signal separation unit 51 (51-1, 51-2, 51)
-3) and the signal adding unit 52 (52-1, 52-2, 52)
-3) and O / E.53 (53-1, 53-2, 53-
3) and E / O.54 (54-1, 54-2, 54-
3) is provided.

The signal separation unit 51 (51-1, 51-2, 5
1-3) is a multiplexed signal (main signal λ1 + monitoring signal λ♯).
1), the multiplexed signal (main signal λ2 + monitoring signal λ♯2), (main signal λ3 + monitoring signal λ♯3), and OTS signal λ * receive the combined optical signal and receive main signal λ1 + main signal λ2 +
This section separates the main signal λ3 from the monitoring signal λ1 + the monitoring signal λ2 + the monitoring signal λ3 + the OTS signal λ *. Further, the main signal λ1 + main signal λ2 + main signal λ3 is transferred to the duplexer 2, and the monitoring signal λ1 + monitoring signal λ2 + monitoring signal λ3 + OT
It is also a part for transferring the S signal λ * to the O / E · 53. The configuration of the signal separation unit 51 (51-1, 51-2, 51-3) will be described with reference to the drawings.

FIG. 11 is a block diagram of a signal separating unit according to the fourth embodiment. As shown in FIG. 11, the signal separation unit 51-
1 (the same applies to 51-2 and 51-3) includes a main signal separation filter 55 and a monitoring signal separation filter 56. The main signal λ1 + main signal λ2 + main signal λ3 and the monitoring signal λ1 +
Reference numeral 60 indicates the frequency assignment of the monitoring signal λ2 + the monitoring signal λ3 + the OTS signal λ *.

The main signal separation filter 55 includes a multiplexed signal (main signal λ1 + monitoring signal λ♯1) and a multiplexed signal (main signal λ2
+ Monitoring signal λ♯2) and (main signal λ3 + monitoring signal λ♯)
3), receiving the OTS signal λ * and receiving the main signal λ1 + main signal λ2 + main signal λ3, and the monitoring signal λ1 + monitoring signal λ2 +
This is a part that separates the signal into a monitoring signal λ3 and an OTS signal λ *.
The main signal λ1 + main signal λ2 + main signal λ3 is transferred to the duplexer 2-1, and the monitor signal λ1 + the monitor signal λ2 + the monitor signal λ3
The + OTS signal λ * is transferred to the monitor signal separation filter 56.

As the main signal separation filter 55, a multilayer filter or the like whose transmission band is designed to be wide is usually used. The monitoring signal separation filter 56 receives the monitoring signal λ1 + the monitoring signal λ2 + the monitoring signal λ3 + from the main signal separation filter 55.
This section receives the OTS signal λ *, separates the signal into a monitor signal λ1, a monitor signal λ2, a monitor signal λ3, and an OTS signal λ * and transfers them to the O / E 53. As an example, 1
The output of the four-input optical coupler is configured by adding a multilayer filter or the like that transmits only the monitoring signal λ1, the monitoring signal λ2, the monitoring signal λ3, and the OTS signal λ *.

The description of the signal demultiplexing section 51 has been completed above, so returning to FIG. 10 again, the description of the optical node provided in the optical wavelength division multiplexing network system of the fourth embodiment will be continued.
The O / E 53 (53-1, 53-2, 53-3) receives the monitor signal λ1, the monitor signal λ2, and the monitor signal from the signal separation unit 51 (51-1, 51-2, 51-3). λ3 and OT
The S signal λ * is individually received and optically / electrically converted and subjected to a monitoring signal λ1, a monitoring signal λ2, a monitoring signal λ3, and an OT, respectively.
This is a portion that is transferred to the control device section 8 as a control signal corresponding to the S signal λ *.

O / E + E / O.9 (9-1, 9-2, 9
-3) is the intra-office wiring 15 (15-1, 15-2, 15-
3) receiving the optical signal input in the station and performing optical / electrical conversion once, and further converting the main signal (λ1 to λ3) of a predetermined frequency into electric / electrical
This is a part that converts the light and sends it to the optical switch unit 3. O /
E + E / O.13 (13-1, 13-2, 13-3)
Is a part which receives the main signals (λ1 to λ3) from the optical switch unit 3, performs optical / electrical conversion once, further performs electric / optical conversion to an intra-office output of a predetermined frequency, and sends it to the intra-office line.

E / O · 54 (54-1, 54-2, 54)
-3) receives the monitor signal λ1, the monitor signal λ2, and the control signal corresponding to the monitor signal λ3 from the control device unit 8 and performs optical / optical conversion, and performs the monitor signal λ1, the monitor signal λ2, and the monitor signal λ3. And the signal adding unit 52 (52-1, 52-
2, 52-3).

The signal adding section 52-1 (52-2, 52-3)
The same applies to the main signal λ1 and the main signal λ
2. The main signal λ3 is transmitted from the E / O 54-1 to the monitoring signal λ1.
, The supervisory signal λ2 and the supervisory signal λ3, and the multiplexed signal (main signal λ1 + monitoring signal λ♯1), the multiplexed signal (main signal λ2 + monitoring signal λ♯2), and (the main signal λ3 + monitoring signal λ♯). This is the part that combines 3). This signal adding unit 52
-1 (the same applies to 52-2 and 52-3) will be described below with reference to the drawings.

FIG. 12 is a block diagram of a signal adding unit according to the fourth embodiment. As shown in FIG. 12, the signal adding unit 52-
1 (similarly for 52-2 and 52-3) is a monitoring signal multiplexer 5
7 and a multiplexed signal multiplexer 58.

The monitor signal multiplexer 57 outputs the monitor signal λ♯1,
This is a part that receives the monitor signal λ # 2 and the monitor signal λ # 3 and combines the monitor signal λ1 + the monitor signal λ2 + the monitor signal λ3. As an example, a three-input one-output optical coupler is used. The multiplexed signal multiplexer 58 receives the main signal λ1 + main signal λ2 + main signal λ3 from the optical switch unit 3 and receives the monitoring signal λ1 + monitoring signal λ2 received from the monitoring signal multiplexer 57.
+ Combination of the monitoring signal λ3.

Further, this section transfers the main signal λ1 + main signal λ2 + main signal λ3 + monitoring signal λ1 + monitoring signal λ2 + monitoring signal λ3 to the multiplexer 4-1. As an example, a two-input one-output optical coupler is used. OTS providing unit 42 (4
2-1, 42-2, 42-3) and E / O · 44 (44-
1, 44-2, and 44-3) are the same as those in the specific example 3, and the other components are the same as those in the specific example 1. Now that the description of the configuration of the optical node included in the optical wavelength division multiplexing network system of Example 4 has been completed, the operation of Example 4 will be described next.

<Operation of Specific Example 4> The preconditions for the explanation of the operation are determined as follows. The optical node shown in FIG. 10 transmits a multiplexed signal (main signal λ1 + monitoring signal λ♯) from the optical multiplexing link 1-7.
1), a multiplexed signal (main signal λ2 + monitoring signal λ♯2),
It receives a multiplexed signal (main signal λ3 + monitoring signal λ♯3) and an OTS signal λ *, and multiplexes these signals into an optical multiplexing link 1-
9 is sent.

Only the operation of separating and adding the supervisory signal λ♯1, the supervisory signal λ♯2, and the supervisory signal λ♯3 will be described. First, the receiving operation will be described. Signal separation unit 51
-1 is a multiplexed signal (main signal λ1) from the optical multiplexing link 1-7.
+ Supervisory signal λ♯1), a multiplexed signal (main signal λ2 + supervisory signal λ♯2), (main signal λ3 + supervisory signal λ♯3), and O
The TS signal λ * receives the combined optical signal.

The signal separating section 51-1 separates the optical signal into a main signal λ1 + main signal λ2 + main signal λ3 and a monitoring signal λ1 + monitoring signal λ2 + monitoring signal λ3 + OTS signal λ *. The main signal λ1 + main signal λ2 + main signal λ3 is supplied to the duplexer 2-
Transferred to 1. The monitoring signal λ1 + monitoring signal λ2 + monitoring signal λ3 + OTS signal λ * is separated into the monitoring signal λ1, the monitoring signal λ2, the monitoring signal λ3, and the OTS signal λ * and transferred to the O / E 53-1.

The O / E 53-1 receives the monitor signal λ1, the monitor signal λ2, the monitor signal λ3, and the OTS signal λ * individually, and performs optical / electrical conversion to each of the monitor signal λ1 and the monitor signal λ1. The control signal is transferred to the control unit 8 as a control signal corresponding to the signal λ2, the monitoring signal λ3, and the OTS signal λ *.

Next, the transmission operation will be described. E / O ・
54-1 receives the monitor signal λ♯1, the monitor signal λ♯2, and the control signal of the electric signal corresponding to the monitor signal λ♯3 from the control device unit 8 and performs the electrical / optical conversion, and performs the monitor signal λ♯. 1 and
The supervisory signal λ♯2 and the supervisory signal λ♯3 are generated and transferred to the signal adding unit 52-1. The signal adding unit 52-1 outputs the main signal λ1, the main signal λ2, and the main signal λ3 from the optical switch unit 3.
And a monitoring signal λ♯1 from the E / O · 54-1;
The supervisory signal λ♯2 and the supervisory signal λ♯3 are received and multiplexed into six waves.

The signal adding section 52-1 transfers this optical signal to the multiplexer 4-1. The multiplexer 4-1 converts the optical signal into a multiplexed signal (main signal λ1 + monitoring signal λ♯1). Multiplexed signal (main signal λ2 + monitoring signal λ 信号 2) and multiplexed signal (main signal λ3 + monitoring signal λ♯3), and
Transfer to 1. Here, after the OTS signal λ * is added, it is transferred to an adjacent node via the optical multiplex link 1-9. Here, the operation of adding the OTS signal λ * is the same as that of the third embodiment, and the other operation is the same as that of the first embodiment.

<Effect of Specific Example 4> As described above,
The following effects are obtained by providing the signal separation unit and the signal addition unit. 1. The monitoring signals (λ♯1, λ♯2, λ♯3,...) Can be changed on the way without being fixed from the front end to the rear end of the wavelength path. 2. As a result, the range of operation of the optical wavelength division multiplexing network system can be expanded. As an example, it is possible to change the wavelength of a light wave in the middle of a wavelength path.

<Structure of Embodiment 5> FIG. 13 is a block diagram of an optical node provided in the optical wavelength division multiplexing network system of Embodiment 5. As shown in FIG. 13, the optical nodes provided in the optical wavelength division multiplexing network system of the specific example 5 are the optical multiplex links 1 (1-1, 1-7, 1-8, 1-9, 1-10, 1-
11), a demultiplexer 2 (2-1, 2-2, 2-3), an optical switch unit 3, and a multiplexer 4 (4-1, 4-2, 4-3).
And O / E + E / O.9 (9-1, 9-2, 9-3)
And O / E + E / O.13 (13-1, 13-2, 13
-3) and the OTS providing unit 42 (42-1, 42-2, 4
2-3) and E / O · 44 (44-1, 44-2, 44)
-3) and the signal separation unit 51 (51-1, 51-2, 51)
-3) and the signal adding unit 52 (52-1, 52-2, 52)
-3) and E / O · 54 (54-1, 54-2, 54-)
3) An O / E 61, an electric signal separation unit 62, a monitoring signal modulation unit 63, and an OTS signal modulation unit 64 are provided.

The O / E 61 is a signal separation unit 51 (51-
1, 51-2, 51-3), which receives the monitoring signal λ1 + monitoring signal λ2 + monitoring signal λ3 + OTS signal λ *, performs optical / electrical conversion in the multiplexed state, and transfers it to the electrical signal separation unit. The electrical signal separating unit 62 receives the monitor signal λ1 + monitoring signal λ2 + monitoring signal λ3 + OTS signal λ * converted from the O / E · 61 into an electrical signal, and monitors the electrical signal monitoring signal λ1 and the electrical signal monitoring signal λ2. , An electrical signal monitoring signal λ3 and an electrical signal OTS signal λ *, which are separately transferred to the control unit 8.

The monitor signal modulating section 63 is a section for individually modulating subcarriers (electric signals) having different frequencies with the monitor signals λ1, λ2, and λ3, respectively. The OTS signal modulating section 64 is a section that individually electrically modulates the subcarrier having a frequency different from the subcarrier of the monitoring signal modulating section 63 with the OTS signal λ * for each optical multiplex link. The other configuration is the same as that of the specific example 4, and the description is omitted.

<Operation of Embodiment 5> The difference from the operation of Embodiment 4 is that the monitor signal λ1 + the monitor signal λ2 + the monitor signal λ3 + O
Since only the processing operation of the TS signal λ * is performed, this processing operation will be described separately for the receiving side and the transmitting side. First, the processing operation on the receiving side will be described. FIG. 14 is an explanatory diagram of the receiving-side signal processing of the specific example 5. From FIG. 14, the signal separation unit 51-1 (the same applies to 51-2 and 51-3) of the specific example 5 (see FIG.
The main signal separation filter 55 provided in 3) includes a multiplexed signal (main signal λ1 + monitoring signal λ♯1) and a multiplexed signal (main signal λ2 +
Monitoring signal λ♯2) and (main signal λ3 + monitoring signal λ♯3)
And the main signal λ1 + main signal λ
2 + main signal λ3 and a monitoring signal λ1 + monitoring signal λ2 + monitoring signal λ3 + OTS signal λ *. The main signal λ1 + main signal λ2 + main signal λ3 is transferred to the duplexer 2-1, and the monitoring signal λ1 + monitoring signal λ2 + monitoring signal λ3 + O
TS signal λ * is transferred to O / E · 61.

The O / E 61 is a main signal separation filter 55
From the monitoring signal λ1 + monitoring signal λ2 + monitoring signal λ3 + OT
The S signal λ * is received, and the signal is optically / electrically converted in the multiplexed state and transferred to the electric signal separation unit 62. Electric signal separation unit 62
Is the monitoring signal λ converted from the O / E · 61 into an electric signal.
Receiving the 1 + monitoring signal λ2 + monitoring signal λ3 + OTS signal λ *, and monitoring the electrical signal monitoring signal λ1, the electrical signal monitoring signal λ2, the electrical signal monitoring signal λ3, and the electrical signal O
The control unit 8 (FIG. 1)
Transfer to 3).

Here, the monitoring signal λ1, the monitoring signal λ2, the monitoring signal λ3, and the OTS signal λ * will be described later on the transmission side.
Modulated. The electric signal separating unit 62 processes the monitor signals optically / electrically converted in the multiplexed state by the band pass filter and the FM demodulator provided therein, and respectively monitors the monitor signals λ1, λ2, λ3, λ3, The signal is converted into a control signal corresponding to the OTS signal λ * and transferred to the control unit 8.

Next, the processing operation on the transmitting side will be described.
As shown in FIG. 13, the monitoring signal modulator 63 (63-1, 63-
2, 63-3) receive control signals corresponding to the monitor signal λ1, the monitor signal λ2, and the monitor signal λ3 from the control unit 8. The monitoring signal modulator 63 (63-1, 63-2, 63
-3) These monitoring signals are E / O signals obtained by FM-modulating subcarriers having different frequencies for each monitoring signal.
Transfer to 54 (54-1, 54-2, 54-3).

E / O · 54 (54-1, 54-2, 54)
-3) converts a monitor signal obtained by FM-modulating a subcarrier having a different frequency for each monitor signal from light to light, and converts the monitor signal to a monitor signal
1. Generate a monitoring signal λ2 and a monitoring signal λ3. Further, these monitoring signals are transmitted to the signal adding unit 52 (52-1, 52-
2, 52-3) to the monitor signal multiplexer 57 provided inside. FIG. 15 is an explanatory diagram of the transmission-side signal processing of the specific example 5. 15, the multiplex signal multiplexer 58 receives the main signal λ1, the main signal λ2, and the main signal λ3 from the optical switch unit 3, and receives the monitor signal λ と 1 and the monitor signal λ♯ from the monitor signal multiplexer 57. 2 and the supervisory signal λ♯3 are received and six waves are multiplexed.

Returning to FIG. The signal adding unit 52 (52
-1, 52-2, 52-3) (FIG. 13) transfers the multiplexed optical signal to the multiplexer 4 (4-1, 4-2, 4-3). The multiplexer 4 (4-1, 4-2, 4-3) (FIG. 1)
1) receives an optical signal obtained by multiplexing six waves, and receives a multiplexed signal (main signal λ1 + monitoring signal λ♯1) and a multiplexed signal (main signal λ
2 + monitoring signal λ♯2) and the multiplexed signal (main signal λ1 + monitoring signal λ♯1) are transferred to the OTS adding section 42-1 (FIG. 11). Here, after the OTS signal λ * is added, it is transferred to an adjacent node via the optical multiplex link 1-9. Where O
The operation of adding the TS signal λ * is the same as that of the specific example 4, and the description is omitted.

In the above description, the supervisory signal λ1, the supervisory signal λ2, and the supervisory signal λ3 are electrically multiplexed together, converted into one optical signal, multiplexed with the main signal, and the OTS signal λ * is monitored. The configuration in which an optical signal different from a signal is converted to a main signal and multiplexed with the main signal has been described. However, the present invention is not limited to this configuration. That is, it is also possible to adopt a configuration in which the monitor signal λ1, the monitor signal λ2, the monitor signal λ3, and the OTS signal λ * are electrically multiplexed together, converted into one optical signal, and multiplexed with the main signal. Further, in the above description, the electric multiplexing modulation method is described as being limited to the FM modulation, but the present invention is not limited to this method. That is, AM
Other modulation methods such as modulation can be realized.

<Effect of Specific Example 5> As described above, the following effects can be obtained by electrically multiplexing the monitoring signals.
1. When separating the monitoring signal from the main signal, one O / O
Since the signal can be received at E, the wavelength stability and the wavelength setting of the optical signal for transmitting the plurality of monitoring signals can be easily set. As a result, the hardware configuration of the device is simplified. 2. The above effect can be further increased by electrically multiplexing the OTS signal in addition to the monitoring signal.

[Brief description of the drawings]

FIG. 1 is a block diagram of an optical node provided in an optical wavelength division multiplexing network system of a specific example 1.

FIG. 2 is a schematic explanatory diagram of an optical wavelength multiplexing network system.

FIG. 3 is an explanatory diagram of a function of a duplexer.

FIG. 4 is an explanatory diagram of frequency assignment of a main signal and a monitoring signal in a specific example 1.

FIG. 5 is a block diagram of an optical node provided in an optical wavelength division multiplexing network system of a specific example 2.

FIG. 6 is an explanatory diagram of a signal format of a specific example 2.

FIG. 7 is a block diagram of an optical node provided in the optical wavelength division multiplexing network system of the third embodiment.

FIG. 8 is an explanatory diagram of frequency allocation of various signals in a specific example 3.

FIG. 9 is a block diagram of an OTS separation unit.

FIG. 10 is a block diagram of an optical node provided in an optical wavelength division multiplexing network system of a specific example 4.

FIG. 11 is a block diagram of a signal separating unit according to a fourth embodiment.

FIG. 12 is a block diagram of a signal adding unit according to Example 4;

FIG. 13 is a block diagram of an optical node provided in an optical wavelength division multiplexing network system of Example 5.

FIG. 14 is an explanatory diagram of the receiving-side signal processing of the specific example 5.

FIG. 15 is an explanatory diagram of a transmission-side signal process of a specific example 5.

[Explanation of symbols]

1 (1-1, 1-2, 1-3, 1-4, 1-4,1-
6) Optical multiplex link 2 (2-1, 2-2, 2-3) Demultiplexer 3 Optical switch unit 4 (4-1, 4-2, 4-3) Duplexer 6 (6-1, 6) −2, 6-3) Monitoring signal multiplexing section 7 (7-1, 7-2, 7-3) Monitoring signal separation section 8 Control device section

Claims (7)

[Claims] 1. A plurality of nodes are connected via an optical multiplex link. The optical multiplex link between the nodes includes: a main signal for constructing a wavelength path using light waves of a predetermined wavelength;
A monitoring signal by a lightwave having a wavelength different from the predetermined wavelength is multiplexed, and the node includes an optical signal multiplexer having a comb-teeth-shaped transmission region arranged at equal frequency intervals. An optical wavelength multiplexing network system, wherein the monitoring signal is assigned to one of comb-shaped transmission regions, and the monitoring signal is assigned to another one of the comb-shaped transmission regions. 2. The optical wavelength-division multiplexing network system according to claim 1, wherein said comb-shaped transmission area is matched with an ITU grid. 3. The optical wavelength division multiplexing network system according to claim 1, wherein a part of the output of the optical signal multiplexer having a comb-like transmission region arranged at the same frequency interval is received. An optical monitor for branching and outputting; an optical filter for receiving the output of the optical monitor and transmitting only the monitoring signal; and an O / E for photoelectrically converting and transmitting the transmitted light of the optical filter.
An optical wavelength division multiplexing network system comprising: a photoelectric converter, wherein the node is controlled based on an output from the O / E (photoelectric converter). 4. The optical wavelength division multiplexing network system according to claim 3, wherein a frame of the supervisory signal is set without straddling a frame of the main signal, and the wavelength path is switched to a part of the supervisory signal. An optical wavelength division multiplexing network system having information mounted thereon. 5. The optical wavelength-division multiplexing network system according to claim 1, wherein an optical multiplex link between the nodes is different from any wavelength of the main signal and the supervisory signal.
And an OT assigned to a non-transmission area of the optical signal multiplexer.
The S signal is further multiplexed, and the node receives an output of another node preceding the node,
An OTS separating unit that extracts an OTS signal transferred from the preceding other node from the output, and transmits the main signal and the monitoring signal to the optical signal multiplexing; O to transfer to the node
An optical wavelength division multiplexing network system comprising an OTS adding unit for multiplexing a TS signal and transferring the multiplexed TS signal to another subsequent node. 6. The optical wavelength-division multiplexing network system according to claim 1, wherein an optical multiplex link between the nodes is different from any wavelength of the main signal and the monitor signal.
And the OTS signal allocated to the non-transmission area of the optical signal multiplexer is further multiplexed. The node receives an output of another node preceding the node,
An OTS separating unit that extracts the monitor signal and the OTS signal transferred from the preceding other node from the output and transmits the main signal to the optical signal multiplexer, and an optical switch that performs wavelength path switching. A signal adding unit for multiplexing the monitoring signal with the main signal to be output; and an OTS adding unit for multiplexing an OTS signal to be transferred to the subsequent subsequent node with the output of the node and transferring to the subsequent subsequent node. An optical wavelength division multiplexing network system comprising: 7. The optical wavelength division multiplexing network system according to claim 6, wherein the monitor signal and the OTS signal multiplexed on an optical multiplex link between the nodes are electrically multiplexed and further subjected to E / O ( A monitoring signal modulation unit that electrically multiplexes the monitoring signal and the OTS signal; and a node that separates the monitoring signal and the OTS signal that are electrically multiplexed. An optical wavelength division multiplexing network system comprising an electric signal separating unit.