Can the Hybrid CWDM-DWDM System Work for Higher Capacity?

When facing the capacity-hungry issue, have you ever hesitated over which WDM system should be choose? As the CWDM system is a more economical solution for limited expanding capacity while the expensive DWDM solution enables much higher capacity, which one should be chose is really a tough decision. In order to solve the issue, can we deploy a Hybrid CWDM-DWDM system, for not choosing a wrong solution to increase the network capacity? Thereby, both the bandwidth shortage with CWDM solution or the potential bankruptcy with DWDM solution can be avoided. Let’s seeking the answer.

Can the Hybrid CWDM-DWDM System Work?

Can the Hybrid CWDM-DWDM system work for higher network capacity? The answer is yes. In fact, it is an ideal solution for boosting the network capacity, which is designed with merging DWDM and CWDM traffic seamlessly at the optical layer, taking full use of the WDM technology. In a hybrid CWDM-DWDM system, more channels can be added to deal with the limited capacity and reach in a CWDM system. That’s to say, the hybrid CWDM-DWDM system utilizes the DWDM technology to empower CWDM system, by integrating CWDM and DWDM equipment, which offers true pay-as-you-grow capacity growth and investment protection.

In short, the hybrid CWDM-DWDM system is a simple, plug-and-play option that enables more DWDM channels interleaved with the existing CWDM channels, for transmitting more data signals. It gets the utmost out of CWDM and DWDM technologies in a single system that greatly reduces the cost, simplifies the installation and keeps the system flexibility for bigger network capacity.

How to Build a Hybrid CWDM-DWDM System?

In general, a normal complete optical connection can be simply done by using a length of fiber patch cable to connect two fiber transceivers and then separately inserting the two transceivers into the ports of two switches. While in a hybrid CWDM-DWDM system, both the CWDM Mux Demux and DWDM Mux Demux should be added offering multiple channels to multiplex and demultiplex the signals. Here offers a typical 44 channel hybrid CWDM-DWDM system information for your reference.

From the figure, we can learn that the original CWDM system uses two 8 channel CWDM Mux Demux with wavelengths from 1470 nm to 1610 nm (20nm channel spacing). In order to add more channels for transmitting larger data signals, two pairs of DWDM multi-channel Mux/Demux are deployed separately under the pass band of the existing CWDM filters. In principle, deploying the DWDM multi-channel Mux/Demux in the 1530nm channel can create 25 100 GHz spaced DWDM channels. However, only 19 DWDM channels circled in the following figure are suitable to be added in the hybrid CWDM-DWDM system. It is also the same to the 1550 channel. Hence, this hybrid CWDM-DWDM system totally offers 6 CWDM channels and 38 DWDM channels with less deployment cost but easier installation.

Conclusion

If you come across the capacity-hungry issue and can’t make the decision about which WDM system should be choose for increasing your network capacity, you are highly recommended to deploy a hybrid CWDM-DWDM system. As an economical and future-proofing solution, the hybrid CWDM-DWDM system can completely deal with the issue of bandwidth shortage when building a CWDM system and avoid the potential bankruptcy for a DWDM system. You can just deploy a CWDM system first. Once the capacity the CWDM system offers can’t meet your requirement, you can add DWDM equipment in for more channels to transmit signals. All in all, the hybrid CWDM-DWDM system is an ideal choice that not only costs less for deployment but keeps the flexibility to increase the network capacity.

Dual-Fiber or Single-Fiber CWDM Mux Demux for Higher Capacity Need?

What would you do if your network capacity can not meet your requirement? Will you put more fibers or update your system? In fact, these two methods are not very recommendable. Why? As your fiber cabling infrastructure is limited for adding fibers and high cost is required for upgrading system, these two methods are unworkable or too expensive. Under this condition, using a pair of CWDM Mux Demux to build a CWDM system with higher capacity is highly recommended. The CWDM Mux Demux is regarded as a key component for a CWDM system, as shown below. It can be simply divided into two types, dual-fiber and single-fiber CWDM Mux Demux. To meet the higher capacity need of your system, this post will mainly introduce the basic knowledge of the dual-fiber and single-fiber CWDM Mux Demux and guide you find a suitable fiber optic Mux Demux for building your CWDM system.

Dual-Fiber CWDM Mux Demux

Dual-Fiber CWDM Mux Demux is a passive device multiplexing and demultiplexing the wavelengths for expanding network capacity, which must work in pairs for bidirectional transmission over dual fiber. It enables up to 18 channels for transmitting and receiving 18 kinds of signals, with the wavelengths from 1270 nm to 1610 nm. The CWDM transceiver inserted into the fiber optic Mux port should have the same wavelength as that of Mux port to finish the signal transmission. For instance, the two reliable 4 channel CWDM Mux Demux showed below use four wavelengths, 1510 nm, 1530 nm, 1550 nm and 1570 nm, their corresponding CWDM transceivers also features the same wavelengths.

When the connection above works, the left 4 channel dual-fiber CWDM Mux Demux uses 1510 nm, 1530 nm, 1550 nm and 1570 nm for transmitting 4 kinds of signals through the first fiber, while the right 4 channel dual-fiber CWDM Mux Demux features 1510 nm, 1530 nm, 1550 nm and 1570 nm for receiving the signals. On the other hand, the transmission from the right to left use the same wavelengths to carry another 4 signals through the second fiber, finally achieving the bidirectional signal transmission.

Single-Fiber CWDM Mux Demux

Single-fiber CWDM Mux Demux should be also used in pairs. One multiplexes the several signals, transmits them through a single fiber together, while another one at the opposite side of the fiber demultiplexes the integrated signals. Considering that the single-fiber CWDM Mux Demux transmitting and receiving the integrated signals through the same fiber, the wavelengths for RX and TX of the same port on the Single-fiber CWDM Mux Demux should be different. Hence, if the 4 channel single-fiber CWDM Mux Demux is used for CWDM system, 8 wavelengths are required, the twice time as that of the dual-fiber one.

The working principle of single-fiber CWDM Mux Demux is more complicated, compared to the dual-fiber one. As shown in the figure above, the transmission from the left to right uses 1470 nm, 1510 nm, 1550 nm and 1590 nm to multiplex the signals, transmit them through the single fiber, and using the same four wavelengths to demultiplex the signals, while the opposite transmission carries signals with 1490 nm, 1530 nm, 1570 nm and 1610 nm over the same fiber. As for the wavelength of the transceiver, it should use the same wavelength as TX of the port on the CWDM Mux Demux. For example, when the port of a single-fiber CWDM Mux Demux has 1470 nm for TX and 1490 nm for RX, then a 1470nm CWDM transceiver should be inserted.

Dual-Fiber vs. Single-Fiber CWDM Mux Demux

We always consider whether an item is worth buying according to its performance and cost. In view of the performance, the single-fiber CWDM Mux Demux can carry signals through only one fiber supporting fast speed transmission and saving the fiber resource, while the dual-fiber one requires two fibers for transmission with a higher reliability. Besides, using single-fiber CWDM Mux Demux can be easier to install. In view of the cost, the single-fiber CWDM Mux Demux is much more expensive than the dual-fiber. And the simplex fiber cable also costs higher than duplex fiber cable. Thereby, the whole cost for building single-fiber CWDM system must be much more higher. Like the two sides of the same coin, both the dual-fiber and single-fiber CWDM Mux Demux have their own advantages and disadvantages. Which one you should choose just depends on your system needs and your budget for building the CWDM system.

Original source: http://www.chinacablesbuy.com/dual-fiber-or-single-fiber-cwdm-mux-demux-for-higher-capacity-need.html

Choose the Right SFP+ Transceivers for CWDM Mux Demux

Nowadays, CWDM technology is very popularly used as a easy and economical way to extend the network capacity by carrying several signals with different wavelengths through a signal fiber. If your network capacity is not enough for your daily use, deploying a CWDM system is an ideal choice for you. As the CWDM Mux Demux should be finally linked with the switches in a completed CWDM system, the fiber patch cable and 10G CWDM SFP+ transceiver are required to finish the whole CWDM link. Hence, this paper will mainly introduce the CWDM Mux Demux and choose the right CWDM SFP+ transceivers for the CWDM Mux Demux, which may be helpful for you to fast build a CWDM system.

CWDM Mux Demux–Key Component for CWDM System

CWDM Mux Demux is a key component for CWDM system, which should work in pairs. As an optical module, it can act as a multiplexer or demultiplexer at either end of the fiber cable. This kind of optical Mux Demux is much easier to use than the DWDM Mux Demux, but can not support the network as long as that of the DWDM Mux Demux. In general, it can offers several kinds of wavelengths, usually from 1270nm to 1610nm (20nm spacing), to support the signal transmission at lengths up to 80 km. Meanwhile, the CWDM Mux Demux can be designed with 4 channels, 8 channels, 9 channels, 16 channels and 18 channels for transmitting different amount of signals. To better know how does this kind of WDM Mux work, the following figure offers a reliable 4 channel CWDM Mux Demux duplex transmission design.

From the figure above, we can learn that two CWDM Mux Demux are connected by a length of duplex patch cable, and they are designed with four channels multiplexing the 1470nm, 1490nm, 1510nm and 1530nm over the same fiber. To complete the transmission link, four pairs of CWDM SFP+ transceivers with 1470nm, 1490nm, 1510nm and 1530nm TX and RX should be separately inserted into the ports of these two WDM Mux Demux. When the CWDM system works, the four different signals from the left to the right will be multiplexed in the CWDM Mux, transmitted over the duplex fiber and demultiplexed in the CWDM Demux, and vice versa for the signals from the right to the left.

How to Choose the CWDM SFP+ Transceivers for CWDM Mux Demux?

As mentioned above, the CWDM SFP+ transceivers are required for building a CWDM system which should be correctly inserted into the SFP+ ports of the CWDM Mux Demux. Thereby, here offers three factors that should be taken into consideration when choosing the CWDM SFP+ transceivers for the CWDM Mux Demux.

The first factor is the working wavelengths of the CWDM SFP+ transceivers. In order to ensure the CWDM system performance, the SFP+ transceiver working wavelengths should be the same to the SFP+ ports of the CWDM Mux Demux. Just like the first figure, when the working wavelengths of the first pair of CWDM SFP+ transceivers are 1470 nm, the first ports of the two CWDM Mux Demux should be also 1470 nm, so that the signal with 1470 nm can be successfully transmitted in the CWDM system. As the CWDM working wavelengths are available from 1270 nm to 1610 nm and the channel spacing is 20 nm, there are 18 kinds of working wavelengths for CWDM SFP+ transceivers, as shown in the following figure.

The second factor is the compatibility of the CWDM SFP+ transceivers. As the third party transceivers are more cost effective than the original one, the former kinds are always the choices for most users. However, the users are always unassured about the quality and compatibility of the third party transceivers for their low price. Here FS.COM is recommendable who offers the CWDM SFP+ transceivers fully tested on most famous original brand switches like Cisco, Brocade, Juniper and Arista. FS.COM CWDM SFP+ transceivers are less expensive but can perform as well as the original branded transceivers, without the compatible issue.

The third factor is the transmission distance the CWDM SFP+ transceivers can support. Although the CWDM system can not support the transmission as long as the DWDM one, it still can reach the lengths 80 km. At present, 10G CWDM SFP+ transceiver can be available at lengths of 20km, 40km, 60km, 80km or even longer on the market. Hence, you can also choose the CWDM SFP+ transceivers according to the transmission distance you system needs.

Conclusion

Building a CWDM system for carrying more data signals is a good choice if the existing network has insufficient capacity. To ensure the performance of the whole CWDM link, it is necessasry to choose the right CWDM SFP+ transceivers for the CWDM Mux Demux. From this paper, it can be concluded that there are mainly three factors, the working wavelength, the compatible issue and the transmission distance the CWDM SFP+ supports, should be taken into account when making the decision about which kind of CWDM SFP+ should be selected for the CWDM Mux Demux.

Why Not Use Raman Amplifier to Extend the CWDM Network Reach?

In comparison with the long-haul DWDM network that uses the thermo-electric coolers to stabilize the laser emissions essential, the CWDM network is a more economical solution that features wider wavelength spacing, allowing the wavelength fluctuation of uncooled directly modulated laser diodes (DMLs). But on the other hand, the CWDM network exists the limitation for the uncooled DMLs’ output power and the additional loss of CWDM Mux Demux and optical add/drop modules. These make the CWDM loss budget limited to < 30 dB and the CWDM reach within 80 km. Moreover, when the insertion loss of the dark fiber is higher than our expectation, a decreasing transmission distance may occur. Hence, here offers the Raman amplifier (see the following figure) to extend the CWDM network reach, as an ideal solution.

What’s Raman Amplifier?

Raman amplifier, also referred to as RA, is a kind of optical fiber amplifier based on Raman gain, which is used for boosting optical signals and finally achieving a longer transmission distance. Different from the erbium-doped fiber amplifier (EDFA) and semiconductor optical amplifier (SOA), the RA intensifies the signals through the nonlinear interaction between the signal and a pump laser within an optical fiber, as shown in the figure below.

At present, two kinds of Raman amplifiers are available on the market, the distributed and lumped Raman amplifiers. As for the distributed Raman amplifier (DRA), it uses the optical fiber as the gain medium to multiplex the pump wavelength with signal wavelength, so that the optical signals can be boosted. With regard to the lumped one (LRA), it requires a shorter length of optical fiber for the signal amplification. Both of these two Raman amplifiers are suitable for amplifying CWDM signals and extending the CWDM network reach.

Why Raman Amplifier Is Used for Amplifying CWDM signals?

As we know, the EDFA and SOA are able to strengthen the CWDM signals. But why it is not recommendable for the CWDM network? In fact, they can not perform as well as the RA in the CWDM network for some limitations, which can be learned from the following figure.

The figures above shows various gain bandwidths of these three optical fiber amplifiers for CWDM network, but only the gain bandwidth the RA offers meet the CWDM network demands. To fully serve the CWDM network, the RA usually optimizes the pumping lightwave spectrum to extend the usable optical bandwidth. As for the EDFA, its gain bandwidth can not match well with the channel spacing of the CWDM network requirements. And for the SOA, although it offers the gain bandwidth fit enough for the CWDM network, it is still not suggested for the inherent technical limitations. In details, the SOA has a relatively low saturation power but a high noise figure and polarization sensitivity, compared to other two amplifiers. Hence, the RA is undoubtedly the best choice to strengthen the CWDM signals and lengthen the CWDM network reach.

How Does Raman Amplifier Benefit CWDM Network?

In order to study the benefit of RA for the CWDM network, here offers two sets of research data about the receiver sensitivity, for a bit-error rate (BER) of 10-9 using a pseudo-random bit sequence (PRBS) with a 231-1 word length.

From the figure above, we can learn that the first set of data is resulted from the four channel CWDM network without use of the RA, while the second utilizes the RA. In order to check whether the Raman amplifier benefits the CWDM network, we can take the data of 100km CWDM transmission through singlemode fiber (SMF) as an example. The power penalty of the transmission with a RA are separately -34.4 dBm, -34.2 dBm, -33.2 dBm and -32.3 dBm. It is 0.3 dBm better than the power penalty of the transmission without a RA, at least. Except that, we can also learn that the CWDM network with a RA can transmit the signals through the SMF at lengths up to 150m without any repeater stations, while the network without the RA cannot.

Conclusion

The Raman amplifier is an ideal alternative to the repeater in CWDM network, for intensifying the CWDM signals and extending the CWDM network reach. By using the Raman amplifier, the loss budget of the CWDM network can be increased, which finally achieves a longer transmission. Meanwhile, from the view of cost, the RA and the repeater are almost the same, but the repeater stations should cost much more for constructing and maintaining. Moreover, using the RA in the CWDM network can also gain the loss compensation of OADM. Then, why not use Raman amplifier to extend your CWDM network reach?

Orignially source:

http://www.chinacablesbuy.com/why-not-use-raman-amplifier-extend-cwdm-network-reach.html

Single Fiber Solutions for CWDM and DWDM Networks

It is well known that there are two transmission ways for fiber optical network, single fiber transmission and dual fiber transmission. From the name, it is easy to learn that the fiber amount is the main difference of these two transmission ways. For the dual fiber transmission, there should be totally two optical fibers, one for transmitting signals, and the other for receiving signals. But for the single fiber transmission, it only requires one optical fiber that can transmit and receive signals at the same time. This feature makes the network deployment easier and the network deployment cost lower than that of dual fiber one, especially in WDM network deployment. In this paper, it will mainly introduce the single fiber solution and its applications in CWDM and DWDM networks.

Single Fiber Solution

Single fiber solution can be also called bidirectional (BiDi) solution designed for carrying signals in both sides of one optical fiber simultaneously. When the single fiber network runs, the signals transmitted from the two sides feature different wavelengths to ensure the dual way transmission. Compared to the dual fiber network, the easy-to-deploy single fiber network would be a good choice for those who have limited budgets but need for bigger network capacity. As for its application, it is very popularly used in Point to Point, Ring or linear Add and Drop, where installing new fibers is impracticable or uneconomical. It can be also used for promoting the reliability of an existing dual fiber network, in which there are one optical fiber for work and the other one for protection.

Single Fiber CWDM Network

The single fiber CWDM network enables the signals with different wavelengths to be transmitted through a signal fiber, which results in a network capacity boost in metro and access networks. As each signal beam can be carried via different channel independently, the different data rates and protocols (T1, T3, Ethernet, Serial, etc) can be transmitted for the different users or applications. To better know how does the single fiber CWDM network work, here offers a figure that shows a 8 channel single fiber CWDM network design.

From the figure, we can learn there are two 8 channel CWDM Mux Demux connected by a single fiber for transmitting 16 signals with different wavelengths and the 16 wavelengths are divided into 8 pairs for bidirectional transmission. On the site A, 8 wavelengths are used for transmitting signals and others for receiving signals. While on the site B, the wavelengths for the TX and RX on the CWDM Mux Demux are all reversed to ensure the performance of the single fiber CWDM network. For instance, the 1270 nm on the site A is the first transmitting wavelength but the first receiving wavelength on the site B. As a result, the signal with 1270 nm can be totally transmitted from site A to site B via the single fiber.

Single Fiber DWDM Network

The single fiber DWDM network also takes full use of the wavelength division multiplexing technology that can greatly expand the capacity over the existing optical network, especially for the long transmission network. Compared to the CWDM one, it can be designed with more channels for larger data signals and can support the network with a much longer distance. What’s more, if the transmission distance is too long, the optical amplifier can be used to enhance the signals. On the other hand, all these advantage makes the cost to deploy a single fiber DWDM network much higher than the CWDM one. Besides, here offers the figure of a single fiber DWDM network design for your reference.

The figure shows a complicated a single fiber DWDM network design that uses two 8 channel DWDM Mux Demux in the main link for single fiber transmission. As for the wavelength feature of the TX and RX for the ports on the DWDM Mux Demux, it is similar to the CWDM one, but the channel spacing is denser. What’s more, except for the existing channels in the main single fiber DWDM link, there can be more channels added into the expansion port of the link for carrying larger data signals. In short, although the cost for deploying single fiber DWDM network is so expensive, it is still a good solution that can make full use of the fiber link to transmit more signals at a much longer distance.

Conclusion

Undoubtedly, the single fiber WDM solution is an ideal choice for those who have limited budgets but need for bigger network capacity. As there are two single fiber WDM solutions available, which one to choose just depends on the network need and budget. The single fiber CWDM network would be more economical but can not transmit as much signals as the DWDM one can, while the DWDM is highly recommended for large and long transmission that would cost more.

How to Deploy a Single-Fiber CWDM Network?

Generally, CWDM network designed for expanding the network capacity can be basically divided into two types, dual-fiber and single-fiber CWDM network, according to the optical fiber transmission line. For the dual-fiber CWDM network, its working principle is easy to acquire, which uses the same wavelength for transmitting and receiving each pair of dual-way signals over the duplex fiber cable. However, for the single-fiber CWDM network, the working principle is highly complex that specially works with different wavelengths for transmitting and receiving each pair of dual-way signals over only one fiber. To better understand the single-fiber CWDM network, here will mainly illustrate how does a single-fiber CWDM network work and introduce the components and installation steps for fast deploying a single-fiber CWDM network.

Introduction of Single-Fiber CWDM Network

Single-fiber CWDM network is a kind of WDM network, designed for greatly expanding the network capacity by combining and transmitting several pairs of dual-way signals with different wavelengths over a single fiber, instead of putting more fibers for lager dual-way data transmission need. When the single-fiber CWDM network runs, there are two single-fiber CWDM Mux Demux using two different wavelengths for each pair of dual-way transmission. In details, if the single-fiber CWDM Mux Demux has four channels for dual-way data transmission, then eight different wavelengths divided into four pairs are required for the four channels, as shown in the figure below. To make a comparison, a 4 channel dual-fiber CWDM Mux Demux only needs four different wavelengths for the dual-way transmission.

From the figure above, we can learn that a 4 channel CWDM network needs two reliable 4 channel CWDM Mux Demux connected by a single fiber and four pairs of CWDM transceivers with eight different wavelengths connected to the CWDM Mux Demux, achieving the dual-way transmission. Obviously, each pair of CWDM transceivers have the complete reversed TX and RX. Just taking the first pair of transceivers as example, the first transceiver on the left side uses 1470nm for TX and 1490nm for RX, while the first transceiver on the right side uses 1490nm for TX and 1470nm for RX, reversely. Meanwhile, to ensure the whole dual-way transmission, the ports of the two CWDM Mux Demux should feature the same TX and RX as those of transceivers. Hence, each pair of dual-way signals with two different wavelengths will be smoothly transmitted and received. To better understand how does the single fiber CWDM network work, the following table also lists the four pairs of wavelengths for the TX and RX ports of the two CWDM Mux Demux, which are also totally reversed.

Basic Components for a Single-Fiber CWDM Network

When deploy the single-fiber CWDM network, we should prepare two single-fiber CWDM Mux Demux, two switches, a rack-mount chassis, several pairs of CWDM transceivers and singlemode simplex patch cables that are the basic and essential components for a single-fiber CWDM network. The two switches separately act as the Local unit and Remote unit for the CWDM network, while the CWDM Mux Demux is the main unit of the network that should be fixed and held on the rack-mount chassis and then connected to the switch. To finish the connection between the CWDM Mux Demux and switch, we should insert the CWDM transceivers into the ports of CWDM Mux Demux and use the singlemode simplex patch cables to connect CWDM transceivers with the switch.

Steps for Single-Fiber CWDM Network Deployment

To fast deploy a single-fiber CWDM network, here offers the step by step installation procedure.

Step A: Install the rack-mount chassis in a standard 19-inch cabinet or rack.

Step B: Align the single-fiber CWDM Mux Demux with the chassis shelf, slightly push it to the shelf cavity. And tighten the captive screws once the CWDM Mux Demux is totally inserted.

Step C: Plug the CWDM transceivers into the switch. And also, connect these CWDM transceivers to the corresponding ports on CWDM Mux Demux according to the wavelengths of the TX and RX, with the use of singlemode simplex patch cable.

Step D: Utilize the singlemode simplex patch cable to connect the two CWDM Mux Demux and test the performance of the whole single-fiber CWDM network.

Conclusion

Single-fiber CWDM network is a cost-effective and easy-to-deploy solution that can not only take full use of the available fiber bandwidth in your network but also greatly expand your network capacity. If you are hesitating over upgrading your system for bigger capacity, buy CWDM multi-channel Mux/Demux, CWDM transceivers and other basic components to deploy the single-fiber CWDM network would be a better choice for you.

Originally source:

http://www.chinacablesbuy.com/deploy-single-fiber-cwdm-network.html

Single Fiber CWDM Network Overview

When designing the fiber optical network, we used to choose the duplex fiber cable as the first choice to finish the dual-way transmission, which transmits the dual-way signals via two separate simplex cables from the opposite sides. However, in some typical dual-way applications like working with BiDi fiber optic transceiver, the simplex fiber cable is required to transmit the dual-way signals respectively over only one fiber cable by using two different wavelengths that has a more complicated working principle than the duplex one. If we want to deploy a single fiber CWDM network, the basic principle is similar to simplex fiber cable but would be much more complicated, which will be explained detailedly in this post.

What Is the Single Fiber CWDM Network?

Single fiber CWDM network is a special kind of WDM network that can greatly increase the network capacity by combining and transmitting several pairs of signals with different wavelengths over a single fiber, with the aim of supporting several dual-way connections at the same time. To deploy the single fiber CWDM network, a pair of single fiber CWDM multi-channel Mux/Demux and several pairs of CWDM transceivers are needed. When the single fiber CWDM network works, the two single fiber Mux Demux require different wavelengths for each pair of dual-way transmission, which is very different from the dual fiber Mux Demux using the same wavelength for a pair of dual-way transmission. That’s to say, there are only four different wavelengths used for 4-channel dual fiber CWDM Mux Demux, but eight different wavelengths divided into four pairs for 4-channel single fiber CWDM Mux Demux.

How Does the Single Fiber CWDM Network Work?

Before talking about the single fiber CWDM network, let’s take a simple BiDi network as an example first. In the BiDi network, only one simplex fiber cable and a pair of BiDi fiber optic transceivers are required to finish the dual-way connection. In details, the two BiDi fiber optic transceivers should be almost the same but has reversed wavelengths for TX and RX. For instance, if one transceiver with 1490nm for TX and 1310nm for RX is installed in one end of the fiber link, the other one in the opposite end should use 1310nm for TX and 1490nm for RX, as shown in the following figure. Hence, the dual-way signals with two different wavelengths can be transmitted over only one fiber cable.

As for the single fiber CWDM network, its basic principle is similar to the BiDi network but would be much more complicated, which can be also learned from the following figure. In the figure, there are two 4-channel single fiber CWDM Mux Demux connected to each ends of the single fiber, and four pairs of CWDM SFP+ transceivers designed with eight different wavelengths, totally achieving the 4-channel single fiber CWDM network. It is easily to learn that these eight different wavelengths are divide into four pairs and each pair has the complete reversed TX and RX. For instance, the first pair of CWDM transceivers consist of a transceiver with 1490nm for TX and 1310nm for RX in the left side and a transceiver with 1490nm for TX and 1310nm for RX in the right side, thereby a pair of dual-way signals with two different wavelengths will be transmitted through the first channel. To better understand how does the single fiber CWDM network work, the following table lists the eight ports with four pairs of wavelengths for TX and RX that are all reversed to ensure the dual-way transmission.

Conclusion

The single fiber CWDM network can greatly increase the network capacity for transmitting larger dual-way data signals, which is able to combine several pairs of signals with different wavelengths into an integrated signal and carry it through a single fiber. To build a smooth single fiber CWDM network, you should firstly install the CWDM fiber optic transceivers into two switches and then connect them into the channel ports of the two single fiber CWDM Mux Demux, finally use a single-mode simplex fiber cable to link the two CWDM Mux Demux together. Besides, to ensure the performance of the single fiber CWDM network, there are some important factors like light loss, transmission distance, and optical signal dropping and adding should also be taken into consideration.

10G DWDM Network for Economically Expanding Capacity

It can’t be denied that for most users, the capacity and transmission data rate their 10G networks offer sufficiently meet their needs at present. However, for some users, their 10G networks are capacity-hungry that requires more and more fiber optical cables installed for carrying large data. Considering that the available fiber infrastructure is limited, the method of putting more cables would be infeasible or unsuitable once the infrastructure no longer fulfill the growing requirements. Is there any economical solution to solve this issue, except upgrading the network that would cost a lot? The answer is yes. In order to create new capacity at a relatively low price, WDM technology is come up with that enables virtual fibers to carry more data. Since WDM technology has been a cost effective solution to face the capacity-hungry issue, here will offer the economical DWDM SFP+ transceiver and DWDM Mux Demux solutions for you to build the 10G DWDM network, which enables bigger capacity to meet your network needs.

DWDM SFP+ Transceiver

The DWDM SFP+ transceiver is an enhanced version of DWDM SFP transceiver that can transmit signals at 10Gbps–the max data rate, mostly deployed in the dark fiber project in combination with the DWDM Mux Demux. Like other kinds of SFP+ transceivers, it is also compliant to the SFP+ MSA (multi-source agreement), designed for building 10G Ethernet network. However, the working principle of DWDM SFP+ transceiver is much more complicated than that of common SFP+ transceiver due to the DWDM technology.

Generally, the DWDM SFP+ transceiver has a specific tuned laser offering various wavelengths with pre-defined “colors” which are defined in the DWDM ITU grid. The colors of the wavelengths are named in channels and the wavelengths are around 1550nm. Its channels are commonly from 17 to 61 and the spacing between channels is always about 0.8nm. In fiber optical network, the 100GHz C-Band with 0.8nm DWDM SFP+ transceiver is the most commonly used one, while transceivers with other spectrum bands like 50GHz with 0.4nm spacing DWDM SFP+ transceiver are also popular with users.

According to the transmission distance, the DWDM SFP+ transceiver can be divided into two types. One is the DWDM-SFP10G-40 with an optical power budget of 15dB, and the other is the DWDM-SFP10G-80 with an optical power budget of 23dB. As we know, the bigger the optical power budget is, the longer the transceiver will support the 10G network. Hence, the DWDM-SFP10G-40 can transmit 10G signals at lengths up to 40 km, but the DWDM-SFP10G-80 is able to support the same network with a longer distance, 80 km. What should be paid attention to is that the transmission distance can be also affected by the quality and type of the DWDM Mux Demux, the quality and length of the fiber, and other factors.

DWDM Mux Demux

The DWDM Mux Demux is a commonly used type of fiber optical multiplexer designed for creating virtual fibers to carry larger data, which consists of a multiplexer on one end for combining the optical signals with different wavelengths into an integrated signal and a de-multiplexer on the other end for separating the integrated signal into several ones. During its working process, it carries the integrated optical signals together on a single fiber, which means the capacity is expanded to some extent. In most applications, the electricity is not required in its working process because the DWDM Mux Demux are passive.

Unlike the CWDM Mux Demux with 20nm channel spacing, the DWDM Mux Demux has a denser channel spacing, usually 0.8nm, working from the 1530 to 1570nm band. It is designed for long transmission, which is more expensive than CWDM Mux Demux used for short transmission. Meanwhile, it also commonly used the 100 GHz C-band DWDM technique like the DWDM transceiver. As for its classification, there are basically two types according to line type, dual fiber and single fiber DWDM Mux Demux, and six types according to the number of the channels, 4, 8, 16, 40, 44 and 96 channels DWDM Mux Demux. All these types of DWDM Mux Demux are available at FS.COM with ideal prices. To better understand the DWDM Mux Demux, here offers a figure of a stable 8 channel DWDM Mux Demux for your reference.

Conclusion

Taking the cost issue into consideration, deploying a 10G DWDM network is much more economical than upgrading your network from 10G to 40G/100G which almost requires changing out all the electronics in your network. The 10G DWDM network makes full use of DWDM technology to expand the network capacity, which creates virtual fibers to support more data signals. If your 10G network is also capacity-hungry, you are highly suggested to deploy 10G DWDM network to make new capacity. As for the related components the 10G DWDM network needs like transceiver and Mux Demux, you can easily find them at FS.COM. For instance, FS.COM offers the DWDM SFP+ transceivers compatible with almost every brand, including Cisco, Juniper, Brocade, Huawei, Arista, HP and Dell, which have been tested to assure 100% compatibility.

Originally source:
http://www.chinacablesbuy.com/10g-dwdm-network-for-economically-expanding-capacity.html