JP2970527B2 - Optical communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication system using an optical branch, and more particularly to an optical communication system using an optical branch between an optical branch and an optical branch in order to remedy a failure in a transmission line or an optical installation. The present invention relates to an optical communication system such as a star-type subscriber device in which is duplicated.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventionally used star type subscriber unit. Station installation device 61
Are transmitted to the transmission control section 62 by a pair of optical transmission sections 63 ₁ , 63 _{1
As in 2} , a pair of optical receivers 64 ₁ and 64 ₂ are connected. Station-installed device 61 and between the downstream optical branching unit 65 ₁ pair of optical transmitter 63, 63 ₂ are duplicated in the station installation device 61 and a pair of light receiving portions 64 ₁ even while upstream optical branching unit 66,
64 ₂ is duplicated. Each subscriber device 67 _{1 to} 67
_N is a pair of optical transmitters 63 ₁ and 63 ₂ of the station installation device 61.
Either receives via the optical branching unit 65 downstream optical signal to be sent, and each subscriber unit 67 ₁ to 67 _N optical signals of the pair of light receiving portion through the upstream optical branching unit 66 for delivering the 6
4 ₁ , 64 ₂ .

In the star type subscriber unit using the optical branching, the space between the station installation device 61 and the downstream optical branching unit 65 and the space between the station installation device 61 and the upstream optical branching unit 66 are duplicated.
Therefore, there is a possibility that the working-side optical signal and the protection-side optical signal collide in the downstream optical branching unit 65, and it is necessary to prevent this. For this reason, the transmission control unit 6 in the station installation device 61
2 judges whether the working or the protection is based on the reception signals of the pair of optical receiving units 64 ₁ and 64 ₂ , and outputs the output of the protection side in the pair of optical transmitting units 63 ₁ and 63 ₂ . I try to stop it.

[0004]

As described above, in the conventional star-type subscriber unit, the standby circuit and the transmission line are stopped. For this reason, even if any failure has occurred on the protection side, it cannot be detected, and the failure is detected when the switching from the working side to the protection side is actually performed. In this case, even if a failure occurs on the working side and switching to the protection side occurs, there is a possibility that communication may not be possible due to the failure on this side, and reliability due to duplexing cannot be ensured.

Therefore, Japanese Patent Application Laid-Open No. 2-58461 discloses that
When the equipment inside the home is in a power-off state, a line monitoring signal is sent from the office to the downstream subscriber line, and this line monitoring signal is looped back at the home equipment side to be monitored in the office, whereby , So that downstream subscriber lines can be monitored.

[0006] However, in this prior art, when the equipment inside the house is in a power-off state, it goes up and monitors the downstream subscriber line. However, if a failure occurs on the spare side, it cannot be detected. Also, since the line monitoring signal is looped back on the in-home device side when the device on the inside of the home is turned off, when a failure occurs in a circuit that operates while the device on the inside of the home is powered on. However, there is also a problem that this cannot be detected in the power-off state.

Therefore, an object of the present invention is to determine the presence or absence of a failure on the standby side before any switching occurs to the standby side due to the occurrence of some failure on the working side and without power-off. It is an object of the present invention to provide an optical communication system capable of performing such operations.

[0008]

According to the first aspect of the present invention, (a) two sets of an optical transmitting unit and an optical receiving unit are provided, one of the two optical transmitting units being used as a working side and the other as a spare side. The optical signals have different wavelengths and the working side is the working side.
Is placed on the spare side.
By placing a signal indicating Rukoto, different from the station-installed device for outputting in parallel to the transmission path has, (ii) parallel from the station-installed device
Input these signals output in a column and put them together
Branches into multiple, parallel
(C) a plurality of the above-mentioned plurality
Disposed in each of the subscriber unit, an optical signal multiplexing means for multiplexing an optical signal transmitted through the transmission path and the downstream optical branching means different from the two optical transmission unit, (d) the
Disposed in each of a plurality of subscriber apparatus, and the optical signal separating means for separating the wavelength components enter the optical signal multiplexed by the optical signal multiplexing means, (e) a plurality of subscriber instrumentation described above
Disposed in each of the location, the failure existence judging means checks the optical signal of each wavelength component after separation to determine the presence or absence of each failure, (to) a plurality of subscriber apparatus the
It arranged respectively, multiplexing transmission this failure existence judging means is to be transmitted to the station-installed device by multiplexing the transmission data or failure in the transmission of optical signals on either side of the working and spare time of detection has occurred a fault Means and (g) the plurality of subscriptions described above.
Placed in each of the user devices and by the optical signal separating means
The working side of the optical signal of each wavelength component after separation
Signal selecting means for selecting a signal indicating that
Is located on the side of the mobile device,
This indicates that a failure has occurred in the transmission of the working optical signal.
When notified, a failure has occurred in the protection side optical signal transmission.
The working side and the backup side of the two optical transmitters on condition that there is no
An optical communication system is used for
Be prepared.

[0009] In this invention according to claim 1, transmits the optical signal to double the transmission path different from the station-installed apparatus, subscriber wavelengths of these optical signals are multiplexed after converting differently Transmit to the receiving side such as device. The receiving side separates the optical signal for each wavelength and checks the optical signal of each wavelength component after the separation to determine the presence or absence of each fault.
Then, and to transmit the multiplexed transmission data to send it to the station-installed device in the case the circuit of the transmission line and the middle Therefore the failure has occurred. As a result, it is possible for the protection side as well as the working side to always check for a failure on the reception side, and to notify the station installation apparatus of the result. By the way, according to the first aspect of the present invention, the station installation device
Each of the plurality of subscriber units via the optical branching means.
When the optical signals for the service side and the protection side are sent in parallel,
For each of these subscriber units, it is determined whether there is a failure.
ing. Therefore, only some of the subscriber units are active.
It is determined that a failure has occurred in the optical signal and the working side and the protection side
Even if the switch is made, the remaining subscriber unit side
Can be selected without any problem
There is a potential. Therefore, according to the first aspect of the present invention,
Places a signal indicating that it is the working side, and reserves
A signal indicating that the device is
The signal selection means of each device can easily select the working side optical signal.
Options and multiple subscribers
Transmission of the working side optical signal from one of the
Transmission of the optical signal on the protection side
With the working side of the optical transmission unit on condition that no
Station-side installation equipment for working-side protection-side switching means for switching the protection side
Side, and switching from working to standby fails on the standby side.
It is ensured that it can be performed under the condition where no problem occurs.

[0010] In the second aspect of the present invention, according to claim 1, wherein
Combining optical signals and optical signals for each wavelength in optical communication systems
Is separated by a WDM filter.
Features. Even with the same WDM filter,
By switching the input / output direction of the
Long separation can be performed.

[0011]

[0012]

[0013]

[0014]

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows an optical communication system according to an embodiment of the present invention.
An outline of the configuration of a star-type subscriber device as a stem
It is a thing. The station installation device 11 includes a pair of optical transmission units 12.
₁, 12_TwoAnd a pair of optical receivers 13₁, 13_TwoTo
Have been placed. Optical transmitter 12 ₁, 12_TwoAre different wavelengths from each other
Light source, one is working and the other is spare.
ing. Station installation device 11, downstream optical branching unit 14, and upstream
Between the optical branching unit 15, these paired optical transmitting units 12₁, 1
2_TwoAlternatively, the light receiving unit 13₁, 13_TwoDuplicated by
Have been. From the station installation device 11 via the downstream optical branching unit 14
The transmitted optical signal is transmitted to a pair of optical transmitters 12.₁, 1
2_TwoAre the multiplexed optical signals transmitted by
The multiplexed optical signal is split into N optical signals.
First to Nth subscriber units 16₁~ 16_NSend to each
Is done. In addition, these subscriber units 16₁~ 16_NSent from
The output optical signals are multiplexed by N in the upstream optical branching unit 15.
And a pair of optical receiving units 13 in the station installation device 11.₁, 13
_TwoTo be sent. Star type of this embodiment
Subscriber equipment uses separate fibers for upstream and downstream.
A two-core bidirectional communication system is adopted.

FIG. 2 shows the configuration of the downstream optical branching unit. The downstream optical splitter 14 includes a WDM (wavelength multiplexing) filter 21 and an optical splitter 23 for splitting the optical signal 22 multiplexed by the WDM filter 21 into N optical signals. The WDM filter 21 receives the optical signal 2 from the pair of optical transmitters 12 ₁ and 12 ₂ shown in FIG.
4 _1, 24 ₂ is sent. These multiplexes the WDM filter 21, to transmit this light branching 23 is branched into N as an optical signal 25 ₁ to 25 _N to the respective subscriber device 16 ₁ ~ 16 _N shown in FIG. 1 Become.

FIG. 3 shows the structure of the subscriber unit.
It is. First to Nth subscriber units 16₁~ 16_NAre the same
In this case, the first subscription
Device 16₁Will be shown. First subscriber device 16
₁Is the optical signal 25₁A WDM filter 31 for receiving
Each optical signal 32 thus separated₁, 32
_TwoOr second optical receiving unit 3 for separately receiving
3₁, 33_TwoAnd these optical receivers 33₁, 33_TwoSolution
Read received data 34₁, 34_TwoAnd enter
Selector 3 for selectively outputting one as received data 35
6 and the transmission data 37 by the first and second optical receiving units 33.
₁, 33_TwoInformation 38 output from₁, 38_TwoAnd many
The transmission signal multiplexing unit 39 to be multiplexed and the multiplexed data 4
1 and the transmitted optical signal 42₁, 42_TwoStation installation equipment as
A pair of optical receivers 13 of the device 11 (FIG. 1) ₁, 13_TwoSent to
And an optical transmission unit 43. In addition,
1st and 2nd optical receiving part 33₁, 33_TwoOutput from
Warning information 38₁, 38_TwoIs input to the selector 36, and the
Used to control switching.

With the star-type subscriber device having the above configuration,
Are two optical transmission units 12 in the station installation device 11 shown in FIG.
₁, 12_TwoAre the same optical signals at different wavelengths
24 ₁, 24_TwoSend However, send these
Optical signal 24₁, 24_TwoOne of the signal trains
Signal to indicate that there is
Is a signal indicating that it is a spare. here
Is the first optical transmitter 12 for convenience.₁Is set to working
And the second optical transmission unit 12_TwoIs set to the spare side
It will be described as if it were. The downstream optical branching unit 14
Signal 24₁, 24_TwoAre combined and branched into N pieces. With one example
And the first subscriber device 16₁Is the light that is branched after multiplexing
Signal 25₁Will be sent.

In the first subscriber unit 16 ₁ shown in FIG.
This is converted by the WDM filter 31 into an optical signal 32 ₁ of the original wavelength,
32 ₂ to separate each of the light receiving unit 33 _1, 33 ₂ to decode the received optical signal corresponding. These first and second
The optical receivers 33 ₁ and 33 ₂ check the received optical signal, and when a failure occurs, such as when the received optical signal itself has not arrived or when an error has occurred, the alarm information 38 ₁ , and outputs the 38 _2.

In this embodiment, the WDM filter 21 shown in FIG. 2 combines optical signals, and the WDM filter 31 shown in FIG. 3 separates optical signals. Both can use the same type of optical component. In this case, by selecting and setting the input side and the output side of the optical signal, one used as a multiplexer in one case is used as a wavelength separator in another case.

The selector 36 shown in FIG.
Alarms from the optical receiving unit 33 _1, 33 ₂ information 38 _1, 38 ₂
And not shown being adapted to enter the data indicating the working side, and outputs the data indicating the working side as the reception data 35 to select the reception data 34 ₁ based on. However, if any failure occurs only in the first received data 34 ₁ Current use side, the second received data 34 ₂
Can be selected and output as the reception data 35.

[0024] Here, as the case of the first received data 34 ₁ fails, the first subscriber device 16 ₁ of internal failure occurred first subscriber device 16 ₁ only detect a fault There are cases where you do. In such a case, there is a high possibility that no failure has occurred on the working side in the other subscriber devices 16 _{2 to} 16 _N such as the second subscriber device. Therefore, in this case for other subscriber units 16 ₂ ~ 16 _N side, still selects the first received data 34 ₁ to which the selector 36 is outputted from the first optical receiving unit 33 ₁ of the working side Will be. However, the first subscriber device 16 ₁ notifies the station installation device 11 via the transmission signal multiplexing unit 39 that the first received data 34 ₁ has a failure.
The station installation device 11 switches between working and standby. From this point on, will output as received data 35 by selecting the second received data 34 ₂ sent second from the light receiving unit 33 ₂ Any other subscriber units 16 ₂ ~ 16 _N.

As is clear from the above description, the first and second optical receiving sections 33 ₁ and 33 ₂ are both optical signals 32 ₁ and 3 2.
2 ₂ , the first to Nth subscriber units 16 ₁
~ 16 _N is receiving both the working and the spare data 34 _1, 34 ₂
Can be monitored. As a result, the ₂ second light receiving portion 33 which is a pre-side in the preceding description to detect any fault, alarm information 38 ₂ is emitted. The alarm information 38 ₂ is inputted to the transmission signal multiplexing section 39, the optical transmitter 4
3 is transmitted to the station-installed apparatus 11 together with the transmission data 37. Therefore, it becomes possible for the station installation apparatus 11 to detect the occurrence of any failure in the backup circuit or transmission line. Of course, if a failure occurs on the working side according to the same principle, the content is notified to the station-installed apparatus 11 via the transmission signal multiplexing unit 39.

[0026]

As described above, according to the first aspect of the present invention, the station-installed apparatus side is the working side on the working side.
Signal that indicates that the backup is on the standby side
Signal to indicate the signal of each of a plurality of subscriber units.
The signal selection means can easily select the working optical signal.
And one of the subscriber units
Notified that a failure has occurred in the working side optical signal transmission.
The transmission of the optical signal on the standby side
The working side and the protection side of the optical transmitter
A working-side spare-side switching means for switching is arranged. Accordingly
And the working side failed only in some of the subscriber units.
In such cases, the system as a whole can be switched from working to spare.
Make sure that switching is performed under the condition that no failure has occurred on the spare side.
There is an effect that you can get.

According to the second aspect of the present invention, the same
Multiplexing or wavelength separation using a WMD filter
Separation allows easy storage and management of parts,
Cost reduction compared to using separate parts
And become possible.

[0028]

[0029]

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an outline of a configuration of a star type subscriber device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a downstream optical branching unit of the apparatus according to the present embodiment.

FIG. 3 is a block diagram illustrating a configuration of a subscriber device according to the present embodiment.

FIG. 4 is a block diagram showing an example of a conventionally used star-type subscriber device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Station installation apparatus 12, 43 Optical transmission unit 13, 33 Optical reception unit 14 Downlink optical branching unit 15 Uplink optical branching unit 16 Subscriber apparatus 21, 31 WDM (wavelength multiplexing system) filter 23 Optical branching 35 Received data 36 Selector 38 Alarm information 39 Transmission signal multiplexing unit

Claims (2)

(57) [Claims] An optical signal is provided at a different wavelength from one of two optical transmission units, one of which is a working side and the other is a protection side.
A signal indicating that it is the standby side, and the standby side
A station installation device that arranges signals indicating that the signals are transmitted in parallel to different transmission lines, and these signals output in parallel from this station installation device
Input and branch them together into multiple
Downlink optical branching means for transmitting in parallel to the incoming equipment
And optical signal multiplexing means disposed in each of the plurality of subscriber devices and multiplexing optical signals sent from the two optical transmission units via different transmission paths and downstream optical branching means. An optical signal separating unit that is arranged in each of the plurality of subscriber units, receives the optical signal multiplexed by the optical signal multiplexing unit, and separates the optical signal into wavelength components; and is arranged in each of the plurality of subscriber units. is a disorder existence determination means for determining the presence or absence of each failure by checking the optical signal of each wavelength component after separating, is disposed in each of said plurality of subscriber units, the failure existence judging means is a failure Multiplex transmission means for multiplexing transmission data to indicate whether a failure has occurred in transmission of an optical signal on the working side or on the protection side upon detection, and transmitting the multiplexed transmission signal to the station-installed apparatus;
And the optical signal arranged in each of the plurality of subscriber units.
Of the optical signal of each wavelength component after separation by the signal separation means.
Signal selection to select the signal indicating that it is the working side
Means , arranged on the station installation device side, and
If a failure has occurred in the transmission of the working optical signal from either
A failure has occurred in the protection optical signal transmission
Current use of the two optical transmitters, provided that they are not
An optical communication system comprising: a working-side protection-side switching unit that switches between a side and a protection side . 2. Combination of optical signals and optical signals for each wavelength
2. The optical communication system according to claim 1 , wherein the separation is performed by WDM filters .