KR20150139696A - Flexible optical add drop multiplexing system - Google Patents

Flexible optical add drop multiplexing system Download PDF

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Publication number
KR20150139696A
KR20150139696A KR1020140067652A KR20140067652A KR20150139696A KR 20150139696 A KR20150139696 A KR 20150139696A KR 1020140067652 A KR1020140067652 A KR 1020140067652A KR 20140067652 A KR20140067652 A KR 20140067652A KR 20150139696 A KR20150139696 A KR 20150139696A
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KR
South Korea
Prior art keywords
optical
roadm
type
multiplexing system
drop multiplexing
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KR1020140067652A
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Korean (ko)
Inventor
윤지현
박인식
안주헌
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주식회사 뷰텔
주식회사 앨텍
(주)휴먼라이트
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Priority to KR1020140067652A priority Critical patent/KR20150139696A/en
Publication of KR20150139696A publication Critical patent/KR20150139696A/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/29—Repeaters
    • H04B10/291—Repeaters in which processing or amplification is carried out without conversion of the main signal from optical form
    • H04B10/293—Signal power control
    • H04B10/294—Signal power control in a multiwavelength system, e.g. gain equalisation
    • H04B10/2942—Signal power control in a multiwavelength system, e.g. gain equalisation using automatic gain control [AGC]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0201—Add-and-drop multiplexing
    • H04J14/0202—Arrangements therefor
    • H04J14/021—Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
    • H04J14/0212—Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM] using optical switches or wavelength selective switches [WSS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J2203/00—Aspects of optical multiplex systems other than those covered by H04J14/05 and H04J14/07
    • H04J2203/0001—Provisions for broadband connections in integrated services digital network using frames of the Optical Transport Network [OTN] or using synchronous transfer mode [STM], e.g. SONET, SDH
    • H04J2203/0003—Switching fabrics, e.g. transport network, control network
    • H04J2203/0005—Switching elements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J2203/00—Aspects of optical multiplex systems other than those covered by H04J14/05 and H04J14/07
    • H04J2203/0001—Provisions for broadband connections in integrated services digital network using frames of the Optical Transport Network [OTN] or using synchronous transfer mode [STM], e.g. SONET, SDH
    • H04J2203/0073—Services, e.g. multimedia, GOS, QOS
    • H04J2203/0082—Interaction of SDH with non-ATM protocols
    • H04J2203/0085—Support of Ethernet

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optical Communication System (AREA)

Abstract

The present invention relates to a variable optical add / drop multiplexing system. The present invention relates to an optical amplifier for controlling the gain of a WDM signal input and output, and a Wavelength Selective Switch (WSS) of a 1X2 splitter and a 2X1 WSS, A demultiplexer for demultiplexing a signal branched by the 1X2 splitter, a multiplexer for multiplexing a signal input from the transponder, and a dispersion compensator for compensating optical attenuation and chromatic dispersion of the WDM signal, And the branching unit (MDU) is one of an F-ROADM type, a T-ROADM CD type, a T-ROADM CDC type, and a T-ROADM CDCF type. According to the present invention, by providing two degrees of operation and operating in the F-ROADM type, the T-ROADM CD type, the T-ROADM CDC type, and the T-ROADM CDCF type according to the type of the branch coupler, And the network can be efficiently operated.

Description

[0001] FLEXIBLE OPTICAL ADD DROP MULTIPLEXING SYSTEM [0002]

The present invention relates to a variable optical add / drop multiplexing system.

The development of fiber optic amplifiers by erbium ion implantation has contributed to dramatically increase the large capacity and long distance transmission characteristics of optical communication. Over the past decade, the bandwidth of optical communications has steadily increased, and WDM (Wavelength Division Multiplexing) has been introduced into the system, which carries multiple wavelengths on a single fiber to accommodate this increase in bandwidth.

In a WDM transmission network that transmits multi-channel signals through one optical fiber, most of the signals are transmitted with different final destinations. In this way, in the WDM transmission network, it is necessary to branch necessary signals at each node and to combine the signals generated at the nodes. The OADM is a device that performs such a task.

On the other hand, in the conventional transmission network, a Fixed OADM (F-OADM) method is used in which a specific wavelength is allocated to a signal to be branched or combined at a specific node among WDM transmission wavelengths. In the F-OADM, a fixed wavelength filter is used at each node to extract a signal of a predetermined wavelength, and a new signal is inserted using a fixed wavelength laser.

In the conventional F-OADM method, if the wavelength of a base station should be increased or decreased according to the increase or decrease of traffic to a specific node, a technician must directly install and adjust necessary hardware on the node. Therefore, according to the conventional operating system, there is a problem that it is not possible to flexibly cope with the efficient operation of the network in a situation where the amount of traffic is rapidly changed as it is today.

The present invention provides two degrees of orientation and allows the reception of a rapid increase in traffic by operating the F-ROADM type, the T-ROADM CD type, the T-ROADM CDC type, and the T-ROADM CDCF type according to the type of the branch- And to provide a variable type optical branching / combining multiplexing system capable of efficiently operating a network.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned can be understood by the following description and more clearly understood by the embodiments of the present invention. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

In order to achieve the above object, the present invention provides an optical amplifier including an optical amplifier for gain control of a WDM signal input / output, a Wavelength Selective Switch (WSS) of a 1X2 splitter and a 2X1 WSS, (MDU) for demultiplexing a signal branched through the 1X2 splitter and multiplexing a signal input from a transponder, and a dispersion compensating unit for compensating optical attenuation and chromatic dispersion of the WDM signal, And the compensation unit DCxU is characterized in that the branching unit MDU is any one of an F-ROADM type, a T-ROADM CD type, a T-ROADM CDC type and a T-ROADM CDCF type.

According to the present invention as described above, it is possible to provide two degrees of orientation and operate in the F-ROADM type, the T-ROADM CD type, the T-ROADM CDC type, and the T-ROADM CDCF type according to the type of the branch coupler , It is possible not only to accommodate a rapid increase in traffic but also to operate the network efficiently.

1 is a block diagram of a variable optical add / drop multiplexing system according to an embodiment of the present invention.
FIG. 2A is a configuration diagram of an F-ROADM type branch coupler (MDU) according to an embodiment of the present invention;
FIG. 2B is a configuration diagram of a T-ROADM CD type branch coupler (MDU) according to an embodiment of the present invention.
2C is a configuration diagram of a T-ROADM CDC type branch coupler (MDU) according to an embodiment of the present invention.
FIG. 2D is a diagram for explaining a flexible grid of a T-ROADM CDCF type branch coupler (MDU) according to an embodiment of the present invention;
3A is a diagram showing a light loss characteristic curve for each wavelength band.
3B is a diagram showing a light loss characteristic curve for each wavelength band.
FIG. 3C is a view for explaining a phenomenon of spreading of waveform due to chromatic dispersion; FIG.
FIG. 3D is a diagram for explaining a waveform spread phenomenon according to chromatic dispersion; FIG.
3E is a circuit configuration diagram for compensating chromatic dispersion and light attenuation.
FIG. 3F is a graph showing the chromatic dispersion of each C-band channel. FIG.

The above and other objects, features, and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, which are not intended to limit the scope of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to denote the same or similar elements.

1 is a configuration diagram of a variable optical add / drop multiplexing system according to an embodiment of the present invention. Referring to FIG. 1, the variable optical add / drop multiplexing system 102 of the present invention amplifies a WDM signal, and includes an operation unit 104 having a wavelength switching function, a branching unit 110 having a multiplexing and demultiplexing function, A dispersion compensation unit 112 for compensating for optical attenuation and chromatic dispersion, and a WCU 114 for performing monitoring and control functions of the entire system. The variable optical add / drop multiplexing system 102 may be connected to the transponder 120.

The operation unit 104 performs a function of gain control and amplification of input and output of a WDM signal, and performs a function of selecting a wavelength through a Wavelength Selective Switch (WSS). More specifically, the operating unit 104 may include a wavelength selection switch of an optical amplifier 116, a 1X2 splitter 118, and a 2X1 WSS 119 for gain-controlling input and output of a WDM signal.

The optical amplifier 116 may include a BST optical amplifier having an OSC filter for DCC communication and a PRE optical amplifier having a fixed gain with an OSC filter for DCC communication. The optical amplifier 116 can actively cope with SPAN changes of the optical link through gain adjustment using an internal VOA (Variable Optical Attenuator). Preferably, the BST (Booster) optical amplifier has a built-in 1510nm OSC filter and can have a gain of 23dB, a PRE (Pre-Amp) optical amplifier has a built-in 1510nm OSC filter and a fixed gain of 17dB .

The wavelength selection switch may be composed of a 1X2 splitter 118 and a 2X1 WSS 119. The wavelength selective switch may include a direction for branching from the WDM signal input direction of the operation unit 104 to the transponder 120, (Degree) communication path in two directions, which is the output direction of the base station 104.

In one embodiment of the present invention, the operating unit 104 may be duplicated and mounted. Preferably, the operating unit 104 may include a first operating unit 106 and a second operating unit 108. [ Each of the first operating unit 106 and the second operating unit 108 includes a line input port and a line output port for inputting and outputting a WDM signal, an optical amplifier for controlling the gain of a WDM signal input / output input through a line input port, Splitter and a Wavelenth Selective Switch (WSS) of 2X1 WSS, respectively. Therefore, the WDM signal inputted through the line input port of each of the first operation unit 106 and the second operation unit 108 can be set to be branched or passed through the 1X2 splitter. That is, the passed signal is outputted through the line output port of the opposite operating unit, and the branched signal is demultiplexed and output to the transponder 120. [

For example, the signal input through the line input port of the first operation unit 106 may be amplified through the PRE optical amplifier and branched through a 1X2 splitter. The signals branched through the 1X2 splitter are demultiplexed and output to the transponder 120, and the BYPASS signal is output through the line output port of the second operation unit 108. [

Also, since the operation unit 104 is set to the bidirectional communication path, a signal input from the transponder 120 can be output through the line output port of the first operation unit 106 or the second operation unit 108 have.

The branching unit (MDU) 110 demultiplexes the signals branched through the 1X2 splitter, multiplexes the signals input from the transponder 120, and outputs the multiplexed signals. More specifically, the branch coupler 110 can receive a branched or combined signal through up to 40 channels through a common port. The signals input to the branch coupler 110 may be multiplexed or demultiplexed through an A-thermal AWG (Arrayed Waveguide Grating) module, and then output through respective line input ports or line output ports. When the AWG is used, the insertion loss per channel of the branch coupler 110 is 5 dB or less.

In one embodiment of the present invention, the branch coupler 110 may be implemented as any one of an F-ROADM type, a T-ROADM CD type, a T-ROADM CDC type, and a T-ROADM CDCF type. Therefore, the function of the variable optical add / drop multiplexing system of the present invention can be selected only by selecting or replacing the branch coupler 110.

FIGS. 2A to 2D illustrate an F-ROADM type, a T-ROADM CD type, a T-ROADM CDC type, and a T-ROADM CDCF type branch coupler MDU according to an embodiment of the present invention.

Referring to FIG. 2A, the variable optical add / drop multiplexing system including the F-ROADM type branch coupler uses an A-AWG DWDM-based multiplexer and a demultiplexer. Therefore, the wavelength can be assigned to each port, and the directionality of the signal when the operating unit and the branching unit are connected can be fixed.

Referring to FIG. 2B, the variable optical add / drop multiplexing system composed of the T-ROADM CD type branch coupler may include a 2X1 optical switch for selective operation of a signal transmission direction and an optical variable filter (TFA) for wavelength setting have. As shown in FIG. 2B, the 2 × 1 optical switch (Optic Swithch) is connected to the branch coupler to selectively operate the signal transmission direction in the D-1 direction or the D-2 direction, (Optical Tunable Filter (TFA)), it is possible to implement a colorless function that can set the wavelength.

FIG. 2C shows a variable optical splitter / multiplexing multiplexing system including a T-ROADM CDC type branch coupler. Referring to FIG. 2C, the 32X32 optical switch is further included in the branching unit of FIG. 2B, thereby realizing a contentionless function that can change the number of used lines according to the setting of the user. That is, the branch coupler of the T-ROADM CDC type includes a 2X1 optical switch for selective operation of the signal transmission direction, an optical variable filter (TFA) for wavelength setting, and a 32X32 optical switch (non-blocking Photonics Switch, it is possible to implement a colorless function that can set the wavelength, a directionless function that can select D-1 or D-2 direction, and a contentionless function that can set the number of used lines freely.

FIG. 2D shows a flexible grid of a variable optical splitter / multiplexing system including a T-ROADM CDCF type branch coupler. The wavelength-selective switch of the T-ROADM CDC type branch coupler and the optical variable filter (TFA) are connected to the T-ROADM CDCF type branch coupler in the same manner as the T-ROADM CDC type branch coupler of FIG. The Flexible Grid to which the channel is assigned is applied.

In the case of flexible grid, 80 channel Grid conforms to Recommendation of ITU-T G.694.1, and channel 1 of C-Band 50G Spacing 80 channel supports ITU-T 50G Spacing of 1529.55 (196.0 Tera) The channel number is 1561.01 (192.05 Tera) of the ITU-T channel.

The dispersion compensation unit (DCxU) 112 performs a function of compensating for optical attenuation and chromatic dispersion of the WDM signal. Preferably, the dispersion compensating unit 112 compensates the optical attenuation through the BST optical amplifier and the PRE optical amplifier according to the SPAN for each transmission distance, and uses a DCF (Dispersion Compensation Fiber), a DCMx (Dispersion Compensation Module with Filter ).

The signal transmitted through the optical line may have attenuation and chromatic dispersion of the optical power. FIGS. 3A and 3B are diagrams showing optical loss characteristic curves per wavelength band, and FIGS. 3C and 3D are views for explaining a waveform spread phenomenon according to chromatic dispersion.

Since the light emitted from the light source is not a monochromatic light, each color propagates at a different speed and occupies a wider range, which causes the optical signal to become more dispersed. This phenomenon is referred to as chromatic dispersion. Types of chromatic dispersion include material dispersion and structure dispersion, and material dispersion refers to chromatic dispersion caused by the refractive index of the optical fiber material depending on wavelength. Structural dispersion means a spreading phenomenon caused by a change in the speed of light propagation specified by the structure of a waveguide even if the material is not a dispersive material. Generally, since the waveguide material is dispersible, waveguide dispersion and material dispersion can exist at the same time. Tolerance range of chromatic dispersion is less than 16,000 ps / nm for 2.5 Gbps signal and less than 60 ps / nm for 40 Gbps signal.

Such degradation of the optical characteristics may cause ISI (Inter Symbol Interference) phenomenon, which may affect the transmission distance. In DWDM, it is impossible to restore the optical characteristics to secure transmission distance. The optical attenuation is compensated through the optical amplifier according to the transmission distance SPAN, and the chromatic dispersion can be compensated through the DCF (Dispersion Compensation Fiber) and DCMx (Dispersion Compensation Module with Filter) of the PRE optical amplifier. The circuit for compensating chromatic dispersion and light attenuation can be constructed as shown in FIG. 3E.

The chromatic dispersion for each C-band channel per unit km is shown in Table 1 and can be compensated by the DCM module.

Compensated length (km) 20 40 60 80 100 1st to 40th color dispersion deviation 36.2 72.4 108.6 144.8 181 DCMX chromatic dispersion 46 93 139 185 231

For example, when transmitting 100 km, the chromatic dispersion for each channel can be calculated as follows.

Chromatic dispersion by channel = 0.04525 (ps / kmnm) * 100km = 4.525 (ps / nm) / Wavelength-Grid

1 to 40 channel chromatic dispersion variation = 28.96 (ps / nm) / WG * 40 WG = 181 (ps / nm)

The chromatic dispersion control range by the DCM module is 231 (ps / nm), and it is possible to control the chromatic dispersion for each channel in transmission of 100 km.

In an embodiment of the present invention, the variable optical add / drop multiplexing system may further include an operation terminal for remotely controlling operation and management. Operational terminal can use PC supporting MS Windows environment and can support EMS for convenient operation management. The EMS of the operation terminal is displayed in the form of the corresponding system so as to be able to monitor the operation state of the system remotely. The variable optical add / drop multiplexing system of the present invention can be connected on the TCP / IP with the operation terminal through the Ethernet connection port, and the Ethernet port can be connected with 100Base-T.

On the front of the operation terminal, a display indicating Prompt is provided for the system ID in which the current command is executed, and the connection can be made through the DCC between the local WDM and the remote WDM, and through the operation terminal and the Ethernet port in the local station, Continuous management is possible through the terminal. The report and response history through the operation terminal can be set to output through the EMS printer, and a help function for the command input format can be provided.

The operation terminal can report on-demand such as information and status information for operation and management of the system, and can report all the details such as the mounting state of the unit and the signal connection status. In addition, current values for the electrical installation parameters and switch selection parameters may be displayed at the operator ' s request.

Specifically, the main functions that can be performed through the operation terminal include alarm reporting processing, allowing or prohibiting alarm reporting, explaining and inquiring conditions of alarm reporting, permitting / prohibiting logs, setting and inquiring log conditions, Performance management functions such as alarm surveillance (alarm surveillance), stopping and resuming of performance data collection, initialization of performance data, automatic reporting when thresholds are set and exceeded, permission / prohibition of data reporting, Configuration management such as clock control and status reporting, connection setup and release, transfer request and reporting, statistical functions capable of continuously reporting and collecting performance data, and output of various data can be provided .

According to the present invention as described above, it is possible to provide two degrees of orientation and operate in the F-ROADM type, the T-ROADM CD type, the T-ROADM CDC type, and the T-ROADM CDCF type according to the type of the branch coupler , It is possible not only to accommodate a rapid increase in traffic but also to operate the network efficiently.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, But the present invention is not limited thereto.

Claims (11)

An operating unit (RSU) comprising an optical amplifier for gain control of a WDM signal input / output, a wavelength selective switch of a 1X2 splitter and a 2X1 WSS, and being set to a two-directional communication path;
A demultiplexer (MDU) for demultiplexing signals branched through the 1X2 splitter and multiplexing signals input from the transponder; And
A dispersion compensation unit (DCxU) for compensating for optical attenuation and chromatic dispersion of the WDM signal,
Lt; / RTI >
The branching unit (MDU) is one of an F-ROADM type, a T-ROADM CD type, a T-ROADM CDC type, and a T-ROADM CDCF type.
Variable optical add / drop multiplexing system.
The method according to claim 1,
Operation terminal for operation and management remotely via Ethernet connection port
Further comprising
Variable optical add / drop multiplexing system.
The method according to claim 1,
The operating unit (RSU)
A line input port and a line output port for inputting and outputting the WDM signal;
An optical amplifier for controlling a gain of a WDM signal input / output input through the line input port; And
A first operating unit and a second operating unit each including a Wavelength Selective Switch (WSS) of a 1X2 splitter and a 2X1 WSS,
The WDM signal input through the line input port of each of the first operation unit and the second operation unit is set to be branched or passed through the 1X2 splitter, and the passed signal is outputted through the line output port of the opposite operation unit , And the branched signals are demultiplexed and output to the transponder
Variable optical add / drop multiplexing system.
The method of claim 3,
And a signal input from the transponder is output through a line output port of any one of the first operating unit and the second operating unit
Variable optical add / drop multiplexing system.
The method according to claim 1,
The optical amplifier
BST optical amplifier with OSC filter for DCC communication; And
PRE Optical Amplifier with Fixed Gain with OSC Filter for DCC Communication
Containing
Variable optical add / drop multiplexing system.
The method according to claim 1,
The operating unit (RSU)
Adjust the SPAN of the optical link using VOA (Variable Optical Attenuation)
Variable optical add / drop multiplexing system.
The method according to claim 1,
The dispersion compensation unit (DCxU)
The optical attenuation is compensated through the BST optical amplifier and the PRE optical amplifier according to the transmission distance SPAN,
(DCF) and a DCMx (Dispersion Compensation Module with Filter) of the PRE optical amplifier.
Variable optical add / drop multiplexing system.
The method according to claim 1,
The F-ROADM type branch coupler (MDU)
A-AWG DWDM-based multiplexer and demultiplexer are used.
Variable optical add / drop multiplexing system.
The method according to claim 1,
The T-ROADM CD type branch coupler (MDU)
2X1 optical switch for selection of direction of signal transmission; And
Optical Tunable Filter (TFA) for wavelength setting
≪ RTI ID = 0.0 >
Variable optical add / drop multiplexing system.
The method according to claim 1,
The T-ROADM CDC type branch coupler (MDU)
2X1 optical switch for selection of direction of signal transmission;
An optical tunable filter (TFA) for wavelength setting; And
32X32 optical switch for setting the number of used lines
≪ RTI ID = 0.0 >
Variable optical add / drop multiplexing system.
The method according to claim 1,
The T-ROADM CDCF type branch coupler (MDU)
2X1 optical switch for selection of direction of signal transmission;
An optical tunable filter (TFA) for wavelength setting; And
And a 32X32 optical switch for setting the number of used lines,
Characterized in that a dynamic frequency channel is assigned to the wavelength selective switch and the optical variable filter (TFA)
Variable optical add / drop multiplexing system.
KR1020140067652A 2014-06-03 2014-06-03 Flexible optical add drop multiplexing system KR20150139696A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020102268A1 (en) * 2018-11-14 2020-05-22 Nec Laboratories America, Inc. High-density submarine roadm unit with remote wss redundancy

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020102268A1 (en) * 2018-11-14 2020-05-22 Nec Laboratories America, Inc. High-density submarine roadm unit with remote wss redundancy

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