Tag Archives: DWDM OADM

How to Light a DWDM Ring Beyond 10G?

Network layout nowadays is no longer limited by old rules created for early Ethernet networks. The technology and infrastructure devices available currently allows for different network topologies, including bus, star, ring and mesh networks. Each of them has its benefits and drawbacks and can be combined to suit application needs. This article emphasizes on the DWDM ring network configuration, illustrating the approaches to build a fiber ring beyond 10G.

What Is a DWDM Fiber Ring?

A fiber ring refers to the network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node. A ring configuration is designed to withstand a single failure. If there happens to be a failure, the system automatically reconfigure itself.

Similarly, a DWDM ring network includes a fiber in a ring configuration that fully interconnects nodes. Two fiber rings are even presented in some systems for network protection. This ring DWDM topology is commonly adopted in a local or a metropolitan area which can span a few tens of kilometers. Many wavelength channels and nodes may be involved in DWDM ring system. One of the nodes in the ring is a hub station where all wavelengths are sourced, terminated, and managed, connectivity with other networks takes place at this hub station. Each node and the hub have optical add-drop multiplexers (OADM) to drop off and add one or more designated wavelength channels. As the number of OADMs increases, signal loss occurs and optical amplifier is needed.

DWDM ring

How to Create a DWDM Fiber Ring Beyond 10G?

Assuming to build a higher than 10G optical ring using two strands of dark fibers, all nodes in this ring configuration are less than 10km apart and there are 8 nodes in total. Here we illustrate the options for achieving a DWDM ring beyond 10G.

20G Fiber Ring

For a 20G ring, the configuration is rather simple. There is no need for an OADM or Mux/Demux, it is recommend to use an Ethernet switch with two SFP+ ports and a pair of BIDI SFP+ optics.

Items Description
S5800-48F4S High Performance Data Center Switch (48*1GE+4*10GE)
10GBASE-BX SFP+ Generic Compatible 10GBASE-BX SFP+ 1270nm-TX/1330nm-RX 10km DOM Transceiver
10GBASE-BX SFP+ Generic Compatible 10GBASE-BX SFP+ 1330nm-TX/ 1270nm-RX 10km DOM Transceiver
40G Fiber Ring

There are three options for creating a 40G DWDM ring.

1. Use a switch with QSFP+ ports, and using QSFP+ optics in accordance. This can be the most cost-effective option for 40G if you have no future plan for more than 40G on the ring.

Items Description
S5850-48S6Q High Performance Data Center Switch (48*10GE+6*40GE)
40GBASE-LR4 Generic Compatible 40GBASE-LR4 and OTU3 QSFP+ 1310nm 10km LC Transceiver for SMF

2. Use four 10G SFP+ optics and a CWDM OADM. You could even scale up to 18 channels giving you a 180G ring if you were use all 18 CWDM channels and had that large of a OADM or Mux/Demux. First four channels with lower cost SFP+ optics, wavelength 1270nm through 1310nm. Then the next 14 channels 1350nm to 1610nm adopts SFP+ with relatively higher cost. You would need a SFP+ port per channel on both ends, and a passive CWDM OADM.

Items Description
CWDM OADM Single Fiber/ Dual Fiber CWDM OADM, East and West
10GBASE-LR SFP+ Generic Compatible 10GBASE-LR SFP+ 1310nm 10km DOM Transceiver
10GBASE-ER SFP+ Generic Compatible 10GBASE-ER SFP+ 1550nm 40km DOM Transceiver

3. Use 10G DWDM SFP+ optics and a DWDM OADM. You can choose less expensive 100Ghz optics that have up to 40 or 44 channels, or the expensive 50Ghz optics that can reach up to 80 or 88 channels.

Items Description
DWDM OADM Single Fiber/ Dual Fiber DWDM OADM, East and West
10G DWDM SFP+ Generic C40 Compatible 10G DWDM SFP+ 100GHz 1545.32nm 40km DOM Transceiver
10G DWDM SFP+ Generic H50 Compatible 10G DWDM SFP+ 50GHz 1537nm 40km DOM Transceiver
100G Fiber Ring

As for a 100G fiber ring, you can count on Ethernet switches that have 100G QSFP28 uplink ports, along with 100G QSFP28 optics. This would allow a 100G connection each way around the ring.

Items Description
S5850-48S2Q4C Carrier Grade 100G-uplink Switch (48*10GE + 2*40GE + 4*100GE)
100GBASE-LR4 Generic Compatible QSFP28 100GBASE-LR4 1310nm 10km Transceiver

Fiber ring enables more reliability and survivability: if a single link failure should occur – the traffic can simply be sent the other way around the ring. With the pervasiveness of Ethernet technology, the ring architecture is widely adopted to construct a Metropolitan Area Network (MAN), Metro-Ethernet service and school district that uses municipal fiber pathways. Several options for creating fiber ring beyond 10G are presented, along with the optical components needed. Hope this could be informative enough.

How to Use OADM in WDM Network

Adding or Dropping signals of devices on the existing WDM network is very common to service providers. Adding a new fiber optic cable for signal transmission of the devices would cost too much. The using of OADM (Optical Add-Drop Multiplexer) solves this problem easily. A OADM can couple two or more wavelengths into a single fiber as well as the reverse process. Service providers can save a lot of money and installation time by adding OADM into the existing WDM network, if they want to add or drop signal on a single fiber.

WDM Solution

Types and Selection of OADM

OADM is generally deployed in WDM network which includes CWDM (coarse wavelength division multiplexing) and DWDM (dense wavelength division multiplexing). Thus, OADM can also be divided into CWDM OADM and DWDM OADM according to its applications. During the selection of OADM, the fiber count that a OADM should be considered. The most commonly used CWDM OADM can add or drop fiber count of 1, 2 and 4. For DWDM OADM, the fiber counts are usually 1, 2, 4 and 8. The installation environment should also be considered during the selection of OADM. There are mainly three types of OADM with different package form factors: plug-in module, pigtailed ABS box and rack mount chassis. The plug-in modules can be installed in empty rack enclosures. The following shows three CWDM OADM with different package form factor.

 4-channel OADM plug-in module  4-channel rack OADM  4-channel pigtailed oadm
Plug-in module OADM Rack mount OADM Pigtailed ABS box OADM
How to Connect OADM With WDM MUX/DEMUX

In most cases, OADM is deployed with CWDM or DWDM MUX/DEMUX. It is usually installed in a fiber optic link between two WDM MUX/DEMUXs. The following picture shows a CWDM network using a 1-channel dual fiber OADM between two CWDM MUX/DEMUXs. Signals over 1470 nm are required to be added to and dropped from the dual fiber link. On the OADM, there are usually one port for input and one port for output. The OADM can be regarded as a length of fiber cable in the fiber link. The point is the one or more strand of signals is added or dropped when the light goes through the OADM.

1-channel OADM

To better illustrate the using of OADM. Here takes the example of a 4-Channel CWDM OADM. This 4-channel OADM supports wavelengths of 1470nm, 1490nm, 1510nm and 1530nm. West port is connected to a CWDM MUX/DEMUX and the East port in connected to the other CWDM MUX/DEMUX on the other end of this fiber link. Up to 4 different wavelengths of optical signals can be added or dropped. The four Channel ports can be connected to the corresponding CWDM transceivers installed on switches. Then a CWDM fiber link with OADM is finished.

4-channel OADM

OADM Solution

OADM is a cost-effective and easy to use passive fiber optic component, which can provide easy to build and grow connectivity environment for WDM network. FS.COM provides full series of WDM MUX/DEMUX and CWDM OADM and DWDM OADM. Kindly contact sales@fs.com for more details.

CWDM in optical fiber transmission network of comprehensive solutions


1. The background of the project:Radio and television networks in recent business growth is faster in a given area, is the region development education network access project, due to the previous optical fiber network resources is mainly used in cable television network, optical fiber resources is not so rich, many county to the town had no residual fiber resources, to increase the data business, now want to be in the original on the fiber optic cable TV network transmission using again, plus infomation data signals, or want to lay out the other cable?Is the main work, need to solve as many towns in this area belongs to mountainous area, cable laying is not very convenient, considering various factors such as resources, cost, on the radio and television networks company specialized in optical network access technology co., LTD. Shenzhen Fiberstore CWDM system to conduct a comprehensive performance analysis and product testing.And start in areas such as education network access to A project on each node USES many Fiberstore CWDM system equipment.

2. Network topology

The radio and television networks of CWDM project at present is mainly used to implement the education network (10/100 MBPS Ethernet) hybrid transmission signals and the cable television network, the current direction of projects with a total of eight different contact, sharing the 3 sets of Fiberstore the CWDM system equipment.
In this scenario, A computer room – B node transfer 2 10/100 MBPS data signals and A cable TV signal, which is based on WDM CWDM access, two 10/100 MBPS signals after Fiberstore C5002S through Fiberstore HA – WDM multiplexer, and cable television signals and reuse all the way to A single fiber, transfer to the access point B region, middle transmission distance of 50 km, implements and Ethernet cable TV signal on the single fiber CWDM solution of hybrid transmission.
A room – C nodes use sea pegatron C5002S system combined with high speed and CWDM terminal transceiver effectively cooperate with access, realize two-way 10/100 MBPS of hybrid transmission over A single optical fiber.
A-D-E by Fiberstore C5004S system combining various nodes of high speed and the corresponding CWDM transceiver implementation 4 10/100 MBPS signals on A single optical fiber access project, through the high speed connection between each contact, through the terminal CWDM wavelengths optical transceiver connected to A contact switch, after the C5004S system in the computer room 4 different signals, respectively in different wavelengths transmitted to each destination, after D primary school, through high speed download local signal, the remaining 3 to continue down the road signal to the corresponding destination.

CWDM access scheme

1.Save fiber resourcesCWDM (Coarse where division multiplexing) Coarse wavelength division multiplexing system, which USES optical multiplexer in the different optical fiber transmission wavelength multiplexing in a single fiber transmission;On the receiving end of A link, using wavelength multiplexer and then revert to the original wavelength, using optical fiber all the way, on the whole link is solved effectively under the condition of the optical fiber resources extremely nervous network access, this scenario, A, D, E, between transmission on A single fiber and four 10/100 MBPS (also can be 1000 MBPS) signal, A room – B node is in the original cable TV signal transmission on A single fiber loading 2 10/100 MBPS signals, save A lot of fiber resources. 2.More business and high bandwidthCWDM is a according to the practical application to the transfer rate of adaptation based transmission platform, support a variety of business transfer.At each wavelength, the support of the business including 10 m / 100 m / 1000 m Ethernet, 155 m / 622 m / 2.5 G of SDH, 155 m / 622 m ATM business, as well as the Fiber Channel business, and so on.The whole system capacity to play a few Gbps data signal.Fully meet user bandwidth requirements in quite some time.This scenario USES is 10/100 MBPS business with cable TV signal for hybrid transmission.

3.Cost-effective, to facilitate the network upgrades

CWDM system than the price of DWDM Multiplexer is relatively low, due to the power of CWDM is small, small volume, easy to use, thus supporting facilities, personnel training and the late maintenance cost is low.Compared with optical cable project: using CWDM device is opened rapidly, low cost, convenient network upgrades, late and increasing need of signal directly, or replace the higher rate of product, don’t need to change the fiber link, convenient network upgrades, reduces the network upgrade costs.The above scenario A-D-E, if change into 1000 MBPS data signals, the capacity of the network directly to upgrade to the 4 GBPS.

CWDM in hybrid access network in the use of the business

With the improvement of people’s living standard, nowadays a single network access gradually cannot satisfy people’s demand for network now, CWDM system support for the characteristics of business more and more get the attention of people, can also provide E, FE, GE, STM 1/4/16 SDH and ATM signaling, CATV video interface and other businesses such as access CWDM system solutions, to meet the requirements of people now.(Read more:DWDM OADM,CWDM Multiplexer,DWDM MUX DEMUX)