Abstract
In this article, we are going to talk about the different advantages that currently represents for companies to be able to carry Fiber Optic links, practically to the desk of their employees, likewise, we will talk about the great advantages that this entails for companies companies dedicated to the design and installation of networks, both for the business area and for domestic users, from large multinational corporations, to the thousands of homes that have pro cable television, telephone, Internet services, etc. In the same way, we will talk broadly about the history of fiber optics, its application as a transmission medium and the future of fiber.
Introduction
Today, the importance of communications has grown considerably, to the point where it has become vitally important to the lives of companies (as well as people).
It is extremely difficult to imagine life without a telephone, without Internet, without Chat, without Messenger, without television, without email, in short, without remote communication channels.
This importance is what has created a requirement for the channels through which the information that we wish to send (or receive, as the case may be) is transmitted. We are interested in ensuring that information travels quickly, safely, and integrates.
Background of telecommunications networks
For many years, the human being has established communication channels. There is evidence that since 200 BC, ancient civilizations used relay messengers on foot (or on horseback) to send messages. If the relay stations were in line of sight, smoke signals were sometimes used instead of physically sending the messenger and, as you might imagine, these signals could not be very complex.
This changed radically in 1973, when Claude Chappe invented the optical telegraph: a signal system that could reach great distances, based on a kind of traffic light with certain degrees of movement, with which hundreds of symbols could be encoded.
With this optical telegraph, the first telecommunications network in Europe was built between the years of 1793 and 1852.
In 1880, Alexander Graham Bell invented the photophone, with which he demonstrated that the voice could be transmitted in a beam of light. Bell focused a beam of light on a thin mirror, while speaking the sound waves made the mirror vibrate, and the amount of energy that was transmitted to the light detector varied in intensity in a corresponding way.
During the subsequent years and up to 1970, with the experiments carried out in the BELL laboratories and the developments of laser diodes that could operate at room temperature, based on a hetero-junction structure, a great interest was aroused in optical communications, because the laser represented a coherent optical source that could provide an information capacity one hundred thousand times greater than that of a microwave system.
With the potential that optical communications could provide, in the mid-70's experiments were carried out that used the atmosphere as a communication channel (which years later would be manifested as wireless networks), later an attempt was made to transmit by various means, such as the water, until the idea of using glass to transmit the light signals emitted by a laser was introduced, however the loss of light was too great, until 1949, when after many years of research, it was decided to use a coating on the glass In order to avoid the excessive loss of light, and with this principle of transmitting light through a glass rod inside a tube, the optical fiber was created.
Even with the advances obtained so far, the loss represented by the use of glass made it inadequate for data transmission, therefore, it made it inoperative for long-distance telecommunications networks.
After many years of research with unfavorable results, the construction of fibers based on Silicon doped with germanium (to increase refraction) or with fluorine (to decrease refraction) was achieved.
Today, optical fibers are extremely compact, high-purity glass filaments: the thickness of a fiber is similar to that of a human hair. Manufactured at a high temperature based on silicon, their manufacturing process is controlled by computers, to allow the refractive index of its core, which is the guide of the light wave, to be uniform and avoid deviations, among its main characteristics it can be mentioned that they are compact, light, with low signal loss, wide transmission capacity and a high degree of reliability due to the fact that they are immune to electromagnetic interference.
Physically, optical fibers are divided into two parts:
- Core: Made of silicon, it is where the information is transmitted which has a diameter of 9mm, 50mm or 62.5mm. Coating: Made of silicon doped with germanium, it is the one that works as a mirror for the core with a diameter of 125mm.
Finally the primary cover, which provides mechanical resistance, color code and protection against humidity to a fiber and a diameter of 250mm
There are basically two types of optical fibers:
- Singlemode: It is a fiber through which a single type of signal is transmitted through the 9mm core. Because it is a very small diameter, the signal in this fiber reaches up to 100Km without having to put a signal amplifier.Multimode: It is a fiber through which several types of signals are transmitted at the same time through the 50mm or 62.5mm core. The disadvantage of this is that the transmission distance is very short compared to single-mode fiber, 5-6Km, so its use only in networks where a high volume of information needs to be transferred at a short distance.
Within the fiber classification, we can find three main types of cables:
OPGW Fiber Optic Guard Cable:
- Fiber Optic Guard Cable has two main purposes:
- Protection against electrical discharges to high power lines in transmission towers. It is enabled as a communication channel with high information transmission capacity. The OPGW cable is composed of a crown of Alumoweld wires on the outside and an aluminum tube where Optical fibers are integrated.
- Self-Supported Dielectric Cables ADSS:
- This type of fiber optic cables has the peculiarity of not having any metal element, which makes it a very light and manageable cable covered by a layer of polyethylene, the element in the cable that gives it mechanical rigidity and tension, are the aramid or kevlar threads, which is what bulletproof vests do with.These cables are designed to suit the project, since the cost of the cable varies depending on the interpostal clearances and whether or not it carries resistance to the tracking effect.
Loose Tube Type Cables:
These cables are installed directly buried or in completely dielectric duct. In addition to being covered by polyethylene, the optical core of the cable has an iron armor.
The boost of fiber optics in telecommunications networks
With all the advances that fiber optics represented, the dream of many was beginning to be cooked, to be able to transmit large amounts of information, over great distances, quickly and reliably, considering that Fiber Optics represents many advantages when compared to cables traditional ones used for data transmission, such as coaxial cable (currently used for the transmission of television signals due to its high bandwidth), or UTP cable, still used in most computer networks.
The main advantages of using fiber optic cable, instead of
copper links are the following:
- Unlike copper, fiber is immune to magnetic fields. Information Capacity, for a single fiber, it can serve more than 5,000 subscribers, while copper requires a 10,000-wire cable Transmission Speed Transmission Distance. Signal Security.
With all these advantages, it seemed that fiber optics would be the answer to the prayers that for years, those in charge of Telecommunications Networks had raised and many companies began to replace their copper trunk cabling with optical cables. However, it is still very difficult to think of having its own fiber optic links in each company or in each house, worse still, in each desk, this due to the high cost involved in the acquisition and installation of this material.
Under this idea, some devices called Media Converters emerged, which as their name indicates, are equipment that allows us to interconnect two different transmission media, in this case, from Fiber Optic to Copper and vice versa.
Currently, we can find in the market manageable and unmanageable media converters (through software or Dip Switches), Switches, Star Concentrators and Multiplexers, Repeaters, Transceivers for 10, 100, 10/100 and Giga Ethernet, ATM, T1 / E1, T3 (DS3) / E3, OC3, OC12, Serial RS-232, RS-422/485, Token Ring and AS / 400 networks. We can consider that the vast majority of users of Fiber Optic channels are Carriers (Integrators and administrators of Local Area Networks (LAN) or a Metropolitan Area Network (WAN) connected to a Central Office (OC) or an End User (CPE))).
Among the current media converters, we find those that are intended for the customer who needs a quality product to convert media without mounting options or DIP switches, generally this is a very basic line and therefore, economical.
Subsequently, we find those that are intended for customers who have a growing network and need mounting options but not SNMP (administration); With these equipments you can have an independent module, Chassis from 5 to 14 slots with redundant source power (AC and DC). They are generally very flexible equipment as they incorporate DIP switches that allow the client to manually force the operating modes on the fiber or UTP side, as well as Auto-sensing 10/100, Full-Duplex or half, Fiber or UTP.
Finally we can find the converters for the client that requires SNMP management, bandwidth control, access to the port on the Fiber Optic and UTP side, it has MIB statistics, TAG Vlan. In this type of converters, the customer chooses the module (in the form of a Nick card), then chooses the chassis, which can be independent, 2-slot, 5-slot, or even 19-slot. These equipments generally have the option of having 1, 2 or 3 redundant source powers (AC and DC), in addition to allowing repairs to be made without affecting the network (without the need to shut down or restart the equipments).
These converters also allow to carry out all their management and configurations by means of a Software, which is very economical and allows the system administrator to make changes in remote places. The modules have DIP switches to make manual changes, but can also force the changes with the software. This ability is something that benefits Telecom Companies, Governments, and Banks. With access to the ports they can also turn on and off the Fiber or UTP side. Telecommunications service provider companies are allowed to control services if their clients do not pay without having to go to the CPE site. This option is excellent for the Government because they have certain hours of operation where they require no services.
Here are some application examples:
First, let's consider a Telecommunications service provider, for an interconnected star network:
In this example, it can be seen how the UTP copper that comes from the Core Switch is converted to fiber through manageable cards mounted in a chassis of 19 manageable modules, and distributed to the end customer (CPE), remote side or to multi users (or place where multiple tenants are needed), where fiber in both cases has to go back to copper and be distributed to end users. The CPE is supplied with a self-managing card as a demarcation point in a single module.
On the multi-user side, it is supplied with two cards, one self-managing and one that acts as a mini switch with 4 copper ports, both mounted in a chassis with 2 manageable modules, with which we obtain 5 copper ports.
This allows us to manage the network, distributing fiber optic links to several clients from the central office and giving different services to different users (since each copper port is independent of each other) with a single pair of fiber threads, Reducing with this the costs in matter of equipment and having the support of the administration including Tag VLAN, port access control, bandwidth control and QoS, among others.
Another application example is the following:
In this case, we consider a ring topology which provides a redundant path that prevents a failure in one station from bringing down the entire network. In this example, two copper UTPs of the network that crosses the main switch are converted into two fiber couplings by means of a 19-Module converter chassis (this according to the size of the network and the central office, since it can also be a 5-module chassis) of the media converters driven by a main converter. One of the two fiber links is distributed to a remote location. At each point we find a chassis with two cards that share Ethernet traffic through the motherboard of each chassis. Traffic from the network core switch enters a fiber port of the media converter,it crosses the Ethernet motherboard, and exits the fiber port of the other media converter, starting a new segment of fiber cascaded to the next location. This configuration is repeated several times until the fiber segment closes the ring with the other fiber coupling. This allows the network manager to move between the different points of the network taking advantage of the fiber ring.This allows the network manager to move between the different points of the network taking advantage of the fiber ring.This allows the network manager to move between the different points of the network taking advantage of the fiber ring.
As we can see in both cases, we can bring fiber to the desktop, or to any desired remote point, according to the needs of each person.
Conclusions
Taking into account the total integrity of a communication system (NETWORK), we can say that manageable media converters have come to revolutionize the way of connection between devices, since we can use the great advantages of fiber optic networks without the need for to absorb the high costs of maintaining an infrastructure like this and we can continue to maintain our current networks, installed in our companies, assuming the low maintenance and installation costs, but having the great benefits of what, in the past, was considered only a dream.
Furthermore, if we consider the practically infinite bandwidth of fiber optics, we can think that Digital Convergence is now a reality, we can consider that the transmission of Voice, Video and Data can be carried out at the same time, by a same medium which is the thickness of a human hair.
For now, we can enjoy this convergence of services, without leaving the door closed to subsequent applications that may be given to telecommunications networks, we can continue dreaming, continue working on research, perhaps, in the not too distant future, we can get the transportation of smells and flavors as well as colors that we now see, and the most impressive, perhaps in a few years, we can go from one place to another, at the speed of light.
Bibliography:
Omnitron Systems Technology Inc., Product Catalog, available at www.omnitron-systems.com
AFL Telecommunications LLC, Cable Catalog, available at www.afl.com
Computer Networks, Andrew S. Tanenbaum, Ed. Mc Graw Hill.
Knowledge and Understanding thematic encyclopedia, Science and Technology section, Ed. Trillas.
Condumex, fiber optic cable catalog, 2003 edition.
Demonstration video: “Manufacture of fiber optic”, available at www.corning.com
CFE E0000-21 specification, for Guard Cables with integrated optical fibers.
