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Arising New Technology Dense Wave Division Multiplexing (DWDM). To outline this new technology I am going to follow the question/answer approach. The question are the following: Describe the major characteristics of DWDM and its future evolution. Question 2. Discuss the main applications and markets for the new products based on DWDM? Question 3. Briefly describe rival technologies? Question 4. Use the knowledge provided above to try and assess the success or failure of each of the DWDM technologies describe?:
Introduction. The need for higher transmission and faster communication
is essential for today’s environments. As we become more impatient and demand
higher standards, there is a need for better technology and more efficiency. In today’s technologies the fiber optics has developed faster and became the way to send information to the other side of the world. But what happens when the fiber that is already in the sea gets used in its totality? Well when we don’t have many choices how do we get more capacity? We can expand capacity in the following ways: 1) Install more fiber (Very expensive and time consuming) 2) Increase system bitrate to multiplex more signals (Already at its maximum) or 3) Wavelength division multiplexing. (New technologies still cost a bit The last choice (WDM) is the preferred one for any major upgrade of band-wide in a fiber optic long distance system, and the Dense Wave Division Multiplexing (DWDM) is more efficient, as many channels can be introduced on a single fiber optics. Within this project I am going to answer four questions. In
part of these answers I am going to give us a brief description, show
applications, discuss rival technologies and talk about success or failure of
these technologies.
Describe the major characteristics of DWDM and its future evolution? The way that this technology evolves is as follows: Firstly, the time division multiplexing (TDM) was introduced. This technology was proven to be very successful as it has been implemented in many industrial applications. It is also very common to myself, as my job involves video multiplexes. This type of video multiplexing recording shares time between video images recorded in a tape. This time slicing pictures get recorded in a decoded way and then when these images are needed they are retrieved from the videotape through a decoding synchronized time division multiplexer. Then the most known to all of us is frequency division multiplexing (FDM). This sort of technology is used in the radio and TV industries to air transmission. This is where for example we get our radio tuned to 104.9 FM. This frequency is one use of many different frequencies. The same is for TV stations. The frequency division occurs within the space spectrum and there are a set of rules and regulations that are set by the Authorize government agents. The medium of transmission in this technology is Air. Then as better transmission was needed in long distance, the wide division multiplexing (WDM) was introduced as it is a more efficient and effective way to use fiber optics. The fiber optics that are already in place in many existing communication, but all used, example the telephone communication between cities and countries. So how does this technology work? Consider that you can see many different colours of light -
red, green, blue, etc. all at once. The colours are transmitted through the air
together and may mix, but they can be easily separated using a simple device
like a prism, just like we separate the "white" light from the sun
into a spectrum of colors with the prism.
So this is how we can decode the light at the end receiver. But how would we put all these different colours of light at the sender end? Well the process is pretty much similar to the decoding end but in reverse. For example single mode fiber, and coupler manufactures learned how to make fused couplers that could separate these signals adequately to allow WDM with simple, inexpensive components. However, these had limited usefulness, as fiber was designed differently for 1300nm and 1550 nm, due to the dispersion characteristics of glass. At this stage this was possible but only with 4 channels per fiber optic and this technology was called wide wave division multiplexing (WWDM). Then come along two new technologies that would improve this latest technology. The first one is dense wide division multiplexing (DWDM) and a second called Coarse Wide Division Multiplexing (CWDM) and combination of CWDM and TDM. This latest one is a more cheaper version than DWDM. In the last years the DWDM was improved taken the initial channel capacity of 16 to a new capacity of 32 channels. Initially those channel band wide capacity were of 2.5Gbit/s per channel, and as this technology grows the DWDM supports 400 wavelengths at 40Gbit/s per channel. Although the wavelength capacity is much higher than the 32 channel, 32 channels is the state of art for this technology. The DWDM uses highly precise filters and temperature stabilized lasers with 1.6nm or less (partly only 0.4nm) that generate 1 wavelength per channel in the 3rd and 4th optical window. So that’s how the DWDM can make many channels work
together in a single fiber. However
the downside is that all this can add up to a very high cost. So far we have talked about the major characteristics of
development of the DWDM, how this is composed and how it was initially started.
Next I will discuss the future evolution into this technology. The future evolution for this technology is in place, and many different companies have research centers in place to continue the development of this new technology. Optus and Telstra use this technology for international communication, and other companies are interested on a piece of that market for the development of that technology. A company situated in Demark by the name of Control Ware is combining this DWDM with other Technology such as TDM and CWDM. This combination is done so that the price cost to consumer is not as high and it is more accessible to the market. This company specializes in video, voice and data communication. Another company that I came across is one that is called IFS and is mainly involved in the transmission of video, voice and data over a single fiber optic. I have used their equipment for a single and a multiple set of cameras and I have found that those devices have supported many types of formats and protocols. This organization is developing different types of multiplexes and at the moment they are able to support up to 16 channel transmission of video with their corresponding voice channels and additional to data channel transmission. As I said before, this technology is the one that is
growing rapidly especially with the support of multinational phone communication
companies. Question 2. Discuss the main applications and markets for the new products based on DWDM?
For submarine cables, DWDM allows us to add band wide and channel capacity without adding fibers and all the overheads involved with the installation and laying of those cables, which can create larger cables and more bulkier and adds more complicated repeaters. So now if the need came to add service in areas where cables are now full is another good application for this technology. This technology can be implemented in any type of installation, submarine and on all land-based short, medium but mainly long distance communication links and new technology may lead to totally new network architectures. A good example may be that the Banks are now locating their main inventory at locations outside of the city perimeter. This is because the cost of buildings in suburbs outside of the metropolitan areas are relatable more cheaper than the same size in city locations. But, that is not the only reason. Big organizations such as the banks have what they call disaster strategies, which means try to separate the information and distribute it around, for many different reasons such as for back up purpose, legal reasons, security reasons and cost reasons. As the technology advances every major organization takes advantages of it and implements those technologies. We can see now that the major banks are buying or I should say leasing black fiber and using this black fiber for different purposes, video conferencing, security surveillance, telecommunication, data transmission just to mention same major uses. But remember that because fiber is already in place in many areas, the leasing of black fiber will became a standard procedure. And to even reduce the cost of the leasing of those black fibers they may even rent unused channels to other private organizations. So in the future, don’t be surprised that we are not only banking with the bank, but also the banks may be leasing us channels of communication between Sydney and Melbourne for example. As I have described previously the main applications are huge, and this new technology can be used in a diverse range of applications, especially in today’s environment where labor cost is rising and technology costs are going down. Technology is becoming more accessible to everyone. I personally believe that in the prospective of new
graduants and the knowledge of this new technology will see us, the newcomers,
as the biggest winners in the demand for technical people with the right
knowledge. So all this makes me think that yes I have made the right decision in
furthering my knowledge in the networking area. NOTE this last paragraph is not
crawling for more marks. Question 3. Briefly describe rival technologies? There are a variety of rivals to this new technology. When I say rival the main concern is the cost. The DWDM is the gold technology and other technologies are much poor in quality or channel quantities, so the other rival technologies advantages are always going to be related to cost. What I mean by that is that yes any other established technology is always going to be less expensive. Next I am going to describe the types of technologies that I have found:
(TDM) Time Division Multiplexes. The time division Multiplexes are used in many different types of applications. It is used for telecommunication, data transmission and one that I am very familiar with, video recording. Of course there are more applications but I am going to talk about video recording that I am very familiar with. Well as we all know the TDM gives a share in time to every device used so that this can be equally shared. The recording of images into a multiplexer happens as followings: The video inputs are connected to a device called a multiplexer. These devices can hold up to 20 cameras at a time. And all this can be recorded into a single videotape or DVR. These images are placed in a sequential format which is decoded when the needs for reviewing occurs. The biggest advantage of this device is the ability to record many different cameras at once making installations more cost effective to the final consumer. The main disadvantage is that because they are sharing time slicing through the recording process then when retrieving those images already recorded, at playback mode these images are being seen as in movies with an interval between picture frames. This interval is acceptable to many types of security recording, but in some cases this recording may not be acceptable at all. Well this is the basic concept behind the time division multiplexing. Data
rate of medium exceeds data rate of digital signal to be transmitted
And the way that it may be
represented graphically is as follows: We can see the time slicing between the channels at the same frequency. (TDM) Time Division Multiplexes
The Frequencies Division Multiplexes are used in the transmission of radio through air and TV stations. The medium of transport in this technology is Air. This media transmission is a very successful one as it has been used for many years. Radio stations used it first and then TV stations and radio aficionados took advantage of this technology. Then came along governments and independent organizations and imposed terms, regulations and cost to this band wide and made it more costly to the end user, and some restrictions made this technology not available to everyone. This FDM sets different frequencies to user and gives a space between frequencies, which makes it more tolerable to interference between radios station (for example 104.1FM and 104. 9FM) we can see that there is 700Khz (or 0.7 Mhz) difference between radios. These separations are all established by government and private organization regulations. This is the basic concept for the frequency division multiplexing.
The way that may be represented
graphically is as follows: We can see the frequency slicing between the channels at the same time. And the way that three voice channel may be separated is as follows:
I will base my next three technologies in this figure Figure A.
(WWDM) Wide Wave Division Multiplexes uses 3 or 4 optical windows in the wavelength. These optical windows are placed well apart as the figure A shows above. The optical wavelength are placed at 1310nm, 14.80nm, 1547nm and 1557 nm, Creating a 4 channels. This implementation is much easier than the other two technologies (DWDM and CWDM). This technology is the first to be used in the placement of different channels in the same fiber optic at different wavelengths. Then again it was proven to be very reliable in the telecommunication application, but yet has not been used much in the small size organizatin. The newer and a more affordable technology (if compared to DWDM) is the one called CWDM Coarse Wide Division Multiplexing. This technology is being developed by many different companies, one of them with the name of Control Ware, and another one with the name of IFS (international fiber System Incorporation). The first one has published a research done by them in a magazine with the name of Interface. This magazine states that cost efficient solutions to medium size application can be done by using the CWDM technology. This technology uses lasers without stabilization with distances of 20nm between 1.470nm and 1.610nm, and this allows the uses of up to 8 channels at a significant lower cost than if we were to use DWDM. So this report indicates that this technology in conjunction with the TDM gets the new name of CWDM Wave Pilot and this new platform is uniquely designed to cost effectively enhance capacity of existing and new fiber connectivity while also incorporating time division multiplexing. They also highlight that this technology was designed to provide the highest standards of flexibility, scalability, reliability and manageability. Control Ware has developed CWDM multiplexer and demultiplexer, that have the capacity to have 8 highspeed channels, or up to 32 low speed channels, and those channel capacitys will range from the 10Mbit/s and 1.25Gbits/s. At the end what everyone tries
to achieve is to have a product that does the job and is affordable to the end
consumer. I was not able to get a price list, but in the overall description of
this technology it was stated that CWDM was much cheaper than DWDM. Question 4. Use the knowledge provided above to try and assess the success or failure of each of the DWDM technologies describe? Before going into every single technology mentioned above, I just need to mention that regardless what sort of technology we used, these technologies are already successful in their own field. Especially knowing that the communication is going to be one fiber optics, this will immediately mean that the signal transmitted is not going to be affected by any FEM induction, noise, spikes, and what is better the security level in this transmission is going to be the best of all technologies. The Success of TDM has already been proven successful, and in today’s transmission is the most used and the cheapest in this range of technology. The telecommunication carriers are the major industries that used the TDM. Of course as the need for more band wide is required these telecommunication carriers are moving to newer technology such as WWDM, CWDM and DWDM. TDM is widely used in the security sector, the implementation of this technology has been proven to be cost efficient and in most instances it has improved the quality of services. FDM is highly used in the media for free to air communication, such as TV, radio and radio aficionados. This technology does not need to be said that it is successful as we know that radio channels and TV stations form part of our life as we listen to the news, watch the weather forecast and so on. The implementation of this technology is used in the fiber optics optical windows, as many video manufacturers make it possible to transport video images at a single fiber by subdividing existing channels to smaller channel by using FDM The WWDM used is the most common channel of the fiber optical windows, is still the affordable of this wide division multiplexes technologies and because of being able to put 4 channels at 4 different wavelength, was the one used for telecommunication backbones. The CDWM was an improved version of WWDM and with the adding of 4 extra channels brought the total capacity to a new level of 8 channels. For the economics reason this technology is still the preferred one for long distance communications, because DWDM is still a new technology and therefore the most expensive. And finally The DWDM the latest technology, has not taken off yet because of the cost of the devices and also as a new technology, it is always the most expensive. But as fiber optics start to get fuller and fiber runs out this technology is going to take off, as we can now integrate up to 32 channels with a wavelength space 200GHz apart. So to finally answer this question I will say that all of the existing technologies including DWDM are going to be still successful, and the only things that are going to indicate which one is to be used is the application based on the price cost of this technology. So if it’s cheaper to put a fiber optic in place a more simple technology is going to be used. BUT if there are kilometers of fiber to be laid in the sea a technology as DWDM will be the most appropriate to use
Conclusion: Through the answers of the above four questions, I was able to show the importance of this new technology DWDM which is the upcoming latest technology in fiber optics. It was easier for me to put as much background as possible
in TDM, FDM and rival competitors to DWDM such as WWDM and CWDM and a
combination of CWDM Wave Pilot. By
doing so I have arrived to the conclusion that these technologies are all
successful in their own rights. The
selection of this technology is going to based in many different aspects such as
cost, functionality and needs. This
makes each application different and the technology to be used for each
application is going to be based on different requirements.
References: Communication Systems, Simon Haykin, 4th Edition, 2001, John Wiley & Sons Inc. Communication Systems, A. Bruce Carlson, 3rd Edition, 1986, McGraw-Hill Inc. Data & Computer Communications, William Stallings, 6th Edition, Prentice Hall International Inc. Computer Networks, Andrew S. Tanenbaum, 3rd Edition, 1996 Prentice Hall International Inc. Control ware communication Systems.http://www.controlware.com.de The Control Ware Communication products international newsletter,. Interface. Issue 1,2002. CWDM http://telecom.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.cableu.net%2Ffibrtech%2Fdwdm.htm
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