Fiber optic communication
Fiber optic communication - communication built on the basis of fiber optic cables. The abbreviation OFL (fiber-optic communication line) is also widely used. It is used in various fields of human activity, from computer systems to structures for communication over long distances. It is today the most popular and effective method for providing telecommunications services.
The fiber consists of a central light conductor (core) - a glass fiber surrounded by another layer of glass - a shell with a lower refractive index than the core. Spreading through the core, rays of light do not go beyond its limits, reflecting off the coating layer of the shell. In a fiber, a light beam is typically formed by a semiconductor or diode laser. Depending on the refractive index distribution and the size of the core diameter, the fiber is divided into single-mode and multi-mode.
Fiber Optic Products Market in Russia
By the beginning of 2009, the family of fiber-optic connectivity technologies had earned itself a fairly good reputation as a viable, scalable option for laying cable broadband access to the global network. Despite the global economic crisis, operators are likely to continue to invest in fiber.
Main article: Fiber optic products (Russian market).
History
2023
An underground internet cable began to be laid in Japan to signal snow falling so that it was removed faster
On November 9, 2023, Japanese corporations NTT and NEC announced the development of technology that allows the use of underground fiber-optic Internet cables to assess snowy city roads. It is assumed that this decision will allow more efficient planning of street clearing during snowfalls in order to ensure uninterrupted traffic. Telecom operator NTT has already begun laying such cables in pilot mode. Read more here.
The world's thinnest fiber optic cable is presented. It is barely noticeable, but it passes traffic 3 times faster
On October 27, 2023, the Indian company STL announced the creation of the world's thinnest fiber optic cable for telecommunications. Its diameter is only 160 microns. The development was presented at IMC 2023, specializing in products invented and produced in India. Read more here.
New synchronization algorithms for optical communication systems with quantum key distribution tested in Russia
Scientists and engineers of JSC Mostkom"," MTUSI KuRaith and joined forces to develop an optimal concept of the system quantum coupling in the atmosphere and, space which is based on a modular approach, which allows with minimal costs to offer a competitive solution to the market for the implementation of high-speed protected communications in the atmosphere. MTUSI announced this on August 1, 2023. Read more here [5]
World Map of Underwater Internet Cables Published
In early March 2023, the Telegeography portal unveiled a global map of underwater Internet cables that connect the country's high-speed data channels around the world.
It is reported that by the beginning of 2023 there were 529 submarine cable systems and 1444 ground connection stations. The total capacity of these lines reached 3.9 Pbit/s: this is almost twice as much as recorded in 2020. Moreover, approximately 82% of the capacity falls on the United States and Canada.
Active development of Internet infrastructure is underway in Europe, Africa and the Middle East. Projects such as Equiano and 2Africa provide the necessary capacity increases in these regions. New connection points in Barcelona, Genoa and Crete are helping to improve the stability of networks. At the same time, Marseille remains the main platform for "landing" cables in the Mediterranean Sea.
In the Asia-Pacific region, it is planned to commission new cables worth more than $6 billion by 2024, which will connect Asia and Oceania. In particular, the Echo and Bifrost highways will be the first cables to directly connect Singapore and the United States. And the Apricot line will connect Japan and Singapore on a track laid east of the Philippines.
In North America, new cables will appear in places such as Virginia Beach and Myrtle Beach on the east coast of the United States. New connection points in Canada and Mexico for the trans-Pacific route are planned on the west coast. In addition, new lines are planned to be laid in Florida.
In South America, with the exception of the already commissioned EllaLink cable, underwater cable connections are focused on the United States. This trend will continue with the planned commissioning of systems such as Firmina, Carnival Submarine Network-1 and AMX-3/Tikal.[1]
In Russia, created a nanoscale fiber for computers of the future
In Russia, created a nanoscale fiber for computers of the future. This project was told at the beginning of July 2023 at the Moscow Institute of Physics and Technology.
A group of scientists from Moscow and St. Petersburg investigated the optical properties of gallium phosphide nanowires and showed that complex optical elements for integrated circuits can be made from these crystals. The researchers made waveguides from its nanocrystals, determined the minimum allowable diameter at which they would transmit light, and created a splitter from the two crystals. Read more here.
Trunk telecom networks in Russia are 75% loaded
The main part of the main fiber-optic communication lines (FOCL) was built in 1995-2005 and is already loaded by more than 75%. This is stated in the "Strategy for the Development of the Telecom Industry until 2035," which the Ministry of Digital Development of the Russian Federation has developed together with the largest telecom operators. The Kommersant newspaper refers to this document in the issue of May 23, 2023.
According to this strategy, the average life of fiber-optic lines is about 20-25 years, and in the period until 2035, trunk networks will have to be replaced, while their work is organized on DWDM equipment (high-speed communication network technology) from foreign manufacturers who have limited supplies to the Russian Federation. But in order to switch to domestic solutions, the communication lines will have to be completely rebuilt.
In addition, as the newspaper writes, such problems as Russia's lag in the speed of fixed networks, stagnation of provider revenues, as well as threats of degradation of telecom infrastructure due to insufficient investment attractiveness of the industry and high capital intensity are traced.
According to experts, by May 2023, the shortage of fiber is growing, so those discounts and grants that the industry plans to provide will not be able to use. In 2022, fiber-optic fiber production in Russia decreased by 77%, and the price of fiber optic increased to 59 thousand rubles per km (since 2019, the growth has been 11.6%).
As noted in the "Strategy for the Development of the Telecom Industry until 2035," the total length of the fiber-optic line in Russia by May 2023 reaches 1.3 million km. At the same time, according to the Telekommunalka Telegram channel, in Russia there are 375.1 thousand km of main lines and 752.2 thousand km of intra-zone lines.
As part of the development of communication networks and the construction of new fiber optic lines, it is proposed to implement a number of projects in the format of public-private partnership with the involvement of funds from the National Welfare Fund to "unbalance traffic" in favor of friendly countries. For example, the launch of projects for the construction of the main network Moscow - (Beijing 6.8 thousand km), Moscow - Delhi (5.9 thousand km), Trans-Caspian transport route (315 km), - Murmansk (Vladivostok along the Northern Sea Route, 12.6 thousand km).[2]
2022
Fiber laying in Russia has sharply decreased to 12 thousand km
In 2022, Russian operators laid less than 12 thousand km of fiber-optic cables on trunk and intra-zone networks, according to data from J'son & Partners Consulting, released in February 2023. In 2021, according to Rosstat estimates, cable laying exceeded 30 thousand km.
According to Rostelecom, in 2022 the company modernized existing and laid over 5,000 km of new fiber-optic communication lines (FOCL) within cities and other settlements. In 2021, the operator laid more than 41 thousand km of fiber-optic communication lines, as discussed in the company itself. It turns out that the volume of construction of trunk communication networks at Rostelecom decreased by 87.8% (by 36 thousand km). However, the company explained that the named 5 thousand km of fiber-optic lines include the construction of new communication lines only within cities and other settlements and, accordingly, do not take into account data on the construction of fiber-optic lines between settlements, for example, as part of a project to eliminate digital inequality or underwater fiber-optic lines to Chukotka (2.2 thousand km).
MTS The statement said that in 2022 the operator laid 12.3 thousand km of fiber-optic lines, and the total length of the line exceeded 272 thousand km.
At the end of November 2022, Alexei Makarkin, commercial director of the Optical Fiber Systems plant in Saransk, said that due to sanctions, the volume of production of Russian fiber decreased by 30-60%, and its cost increased. According to Makarkin, due to the sanctions, the supply chains of raw materials, including glass blanks - preforms, were violated. Previously, the plant purchased raw materials from Japan and the Netherlands, and then began to import from China and India. However, as Makarkin noted, countries fear secondary sanctions, and prices for delivery by plane have increased.[3]
Data transmission via fiber overclocked to a record 1.53 Pbit/s
On November 10, 2022, the Japanese National Institute of Information and Communication Technologies (NICT) announced the establishment of a new data rate record for standard fiber optic cable - more than 1.5 Pbit/s.
In addition to NICT employees, experts from Nokia Bell Labs (USA), Prysmian Group (France and the Netherlands) and the University of Queensland (Australia) took part in organizing the experiment. The bandwidth shown with a margin is enough to transmit all world Internet traffic, which is currently estimated to be a little less than 1 Pbit/s.
The researchers took advantage of a 55-mode optical fiber with a standard diameter. Information was transmitted at 184 wavelengths in the C-band. Prysmian fiber was chosen as the technical components, as well as a multiplexer/demultiplexer designed and manufactured jointly by Nokia Bell Labs and the University of Queensland. Parallel signal generation devices and high-speed receivers are common.
As a result, the data transfer rate reached 1.53 Pbit/s at a distance of 25.9 km. In the future, throughput can be increased by combining several wave ranges. The spectral efficiency was 332 bps/Hz, three times the previous achievement.
Technically, this is not the highest data rate in history. Earlier, other scientists, using a specialized photon chip, were able to achieve an indicator of up to 1.84 Pbit/s. But this project is exclusively experimental in nature, while NICT specialists and partners used conventional diameter fiber. However, the demonstrated technology is unlikely to fall on commercial rails in the near future.[4][5]
Japanese scientists set world data transfer rate record
Japanese The National Institute information telecommunication and Technology (NICT) set a world record for transmission speed. data This became known on June 2, 2022.
Specialists managed to transfer data at 51.7 km at a speed of 1.02 Pbit/s.
The speed of 1 Pbit/s makes it possible to broadcast 10 million video channels per second with a resolution of 8K. This record is 100,000 times faster than the maximum speed of home Internet as of June 2022.
The project was implemented using fiber optic cables compatible with the existing infrastructure. Three bands were used: traditional C and L, as well as experimental S. Thanks to the technology of spectral channel compaction, the throughput increased to 20 THz.
The previous record for a four-core fiber was 610 Tbit/s, and a speed above 1 Pbit/s was achieved only on a 15-core cable[6].
MTUSI specialists have developed an approach to creating multi-channel fiber-optic communication lines
Specialists developed their own approach to creating multi-channel fiber-optic communication lines, MTUSI which became known on June 29, 2022. It is expected that the technique will reduce the cost of services communications and provide a throughput per cable pair of fibers from 100 Terabits per second to 10 Petabits per second. More. here
2021: New data rate record set at 319 Tbit/s
In mid-June 2021, a new technology developed by engineers of the Japanese National Institute of Information and Communication Technologies (NICT) appeared, in which the film is downloaded in 28th split second. This is a new data rate record.
On an optical cable with a length of more than 3000 km, the team reached a data transfer rate of 319 terabits per second (hereinafter Tbit/s). This not only broke the previous record of 178 Tbit/s, but is still compatible with the existing infrastructure, which means that it can be relatively easily upgraded in the coming years.
The new record was set by a team of scientists and engineers led by physicist Benjamin Puttnem of Japan's National Institute of Information and Communication Technology (NICT) and builds on the results of previous work the institute participated in - reaching a speed of 172 Tbit/s, which was announced last year.
In this achievement, a connected three-core optical fiber was used - a technology in which data is transmitted over 3 fiber-optic tubes, and not 1, as is currently customary, this is necessary in order to reduce signal distortion over long distances. The speed of 319 Tbit/s used a similar technology, but with 4 cores.
Data is transmitted using a technique called wavelength division multiplexing. It is transmitted by a laser that splits the signal into 552 channels and transmits it over 4 cores of optical fiber.
After 70 km. the intervals along the fiber amplifiers increase the signal strength so that the transmission losses over long distances are as small as possible. These amplifiers are two new types doped with rare earth elements tulium and erbium.
In general, the average data transfer rate per channel was about 145 gigabits per second (hereinafter GB/s), for each core and about 580 GB/s, for all 4 cores combined. A record speed of 319 Tbit/s was achieved at a maximum of 552 wave channels.
The jacket for the four cores of the optical fiber together has the same diameter as a standard single-core optical fiber, which "is attractive for the early adoption of SDM fibers in high-performance and long-distance communication lines, since this technology is compatible with traditional cable infrastructure and mechanical reliability is expected to be comparable to single-mode fibers," the researchers from the institute themselves noted.
The panel's report itself was presented at the International Conference on Fiber-Optic Communications in June 2021, but the team plans to continue working on its long-distance data transmission system to try to increase both capacity and its transmission range.[7][8]
2020: ITMO modernizes fiber and optimizes data efficiency
On October 22, 2020, it became known that specialists from ITMO University modernized fiber and optimized the efficiency of data transmission. With the help of light capture technology, it was possible to get rid of the "blind spots" that arose at high angles of incidence. "Pumped" fiber can be used to enhance the image of endoscopy and laparoscopy, quantum technologies and fiber optic sensors. The concept proposed by development scientists in 2020 hit the cover of the October issue of ACS Photonics magazine. Read more here.
1970: Invention of Fiber Optic
The invention in 1970 by Corning specialists of fiber optic, which made it possible to duplicate the telephone signal data transmission system over a copper wire by the same distance without repeaters, is considered to be a turning point in the history of the development of fiber optic technologies. The developers managed to create a conductor that is able to store at least one percent of the optical signal power at a distance of one kilometer. By today's standards, this is a rather modest achievement, and then, almost 40 years ago, a necessary condition in order to develop a new type of wired communication.
Initially, the fiber was multiphase, that is, it could transmit hundreds of light phases at once. Moreover, the increased diameter of the fiber core made it possible to use inexpensive optical transmitters and connectors. Much later, fiber of greater productivity began to be used, through which only one phase could be broadcast in an optical environment. With the introduction of a single-phase fiber, the integrity of the signal could be maintained at a greater distance, which contributed to the transmission of considerable amounts of information.
The most popular today is single-phase fiber with zero wavelength offset. Since 1983, it has held a leading position among the products of the fiber optic industry, having proven its performance at tens of millions of kilometers.
1920-1956: Ability to transmit images via optical tubes
In the 1920s, experimenters Clarence Hasnell and John Berd demonstrated the possibility of transmitting images through optical tubes. This principle was used by Heinrich Lamm for medical examination of patients. Only in 1952 did the Indian physicist Narinder Singh Kapani (Narinder Singh Kapany) conduct a series of experiments of their own, which led to the invention of fiber. In fact, he created the same bundle of glass threads, and the shell and core were made of fibers with different refractive indices. The shell actually served as a mirror, and the core was more transparent - so it was possible to solve the problem of rapid dispersion. If previously the beam did not reach the end of the optical filament, and it was impossible to use such a transmission means at long distances, now the problem has been solved. Narinder Kapani improved the technology by 1956. A bundle of flexible glass bars transmitted the image with virtually no loss or distortion.
1840: Experiment with changing the direction of the light beam by refraction
Fiber optics, although it is a ubiquitous and popular means of providing communication, the technology itself is simple and has been developed for a long time. An experiment with changing the direction of the light beam by refraction was demonstrated by Daniel Colladon and Jacques Babinet back in 1840. A few years later, John Tyndall used this experiment at his public lectures in London, and already in 1870 he published a work on the nature of light. The practical application of the technology was found only in the twentieth century.
Advantages of Fiber Optic Communication Type
- Wideband optical signals due to extremely high carrier frequency. This means that information from speed about 1 Tbit/s can be transmitted over the fiber link;
- Very low attenuation of the light signal in the fiber, which makes it possible to build fiber-optic communication lines up to 100 km or more long without signal regeneration;
- Immunity to electromagnetic interference from surrounding copper cable systems, electrical equipment (power lines, electric motors, etc.) and weather conditions;
- Protection against unauthorized access. Information transmitted over fiber-optic communication lines is practically impossible to intercept by non-destructive cable;
- Electrical safety. Being, in fact, a dielectric, optical fiber increases the explosion and fire safety of the network, which is especially important at chemical, oil refining enterprises, when servicing high-risk processes;
- Service life of fiber-optic communication lines is at least 25 years.
Disadvantages of fiber optic communication type
- The relatively high cost of active line elements converting electrical signals into light and light into electrical signals;
- Relatively high cost of optical fiber welding. This requires precision, and therefore expensive, technological equipment. As a result, when the optical cable breaks, the cost of restoring the fiber optic fiber is higher than when working with copper cables.
Fiber Optic Line Elements
- Optical receiver
Optical receivers detect signals transmitted through a fiber optic cable and convert it into electrical signals, which then amplify and then restore their shape, as well as clock signals. Depending on the transmission rate and the system specifics of the device, the data stream can be converted from a series view to a parallel view.
- Optical transmitter
The optical transmitter in the fiber system converts the electrical sequence of data supplied by the system components into an optical data stream. The transmitter consists of a parallel-to-serial converter with a sync pulse synthesizer (which depends on the system setting and the bit rate of information transfer), a driver and an optical signal source. Various optical sources may be used for optical transmission systems. For example, light-emitting diodes are often used in cheap local networks for communication over a short distance. However, the wide spectral bandwidth and the impossibility of working in the wavelengths of the second and third optical windows does not allow the use of an LED in telecommunication systems.
- Preamplifier
The amplifier converts the asymmetric current from the photodiode sensor into an asymmetric voltage, which is amplified and converted into a differential signal.
- Data Synchronization and Recovery Chip
This chip must recover the clock signals from the received data stream and their timing. The phase locked loop required to recover the clock pulses is also fully integrated into the clock chip and does not require external control clock pulses.
- Serial to Parallel Code Conversion Block
- Parallel-to-serial converter
- Laser shaper
Its main task is to supply bias current and modulating current for direct modulation of the laser diode.
- Optical cable consisting of optical fibers located under a common containment.
Single mode fiber
With a sufficiently small fiber diameter and corresponding wavelength, a single beam will propagate through the light guide. In general, the very fact of choosing the diameter of the core for a single-mode signal propagation mode speaks of the specifics of each individual design option of the light guide. That is, single mode should be understood to mean the characteristics of the fiber relative to the particular frequency of the wave used. The propagation of only one beam allows you to get rid of inter-mode dispersion, and therefore single-mode light guides are orders of magnitude more productive. At the moment, a core with an outer diameter of about 8 microns is used. As with multimode light guides, both the step and gradient density of the material distribution is used.
The second option is more productive. Single-mode technology is thinner, more expensive and is currently used in telecommunications. Optical fiber is used in fiber-optic communication lines, which are superior to electronic communication facilities in that they allow digital data to be transmitted over huge distances without loss at a high speed. Fiber optic lines can either form a new network or serve to combine existing networks - sections of optical fiber lines, physically combined at the optical fiber level, or logically - at the data transmission protocol level. The data transfer rate over the fiber optic network can be measured in hundreds of gigabits per second. Already, a standard is being finalized that allows data transfer at a speed of 100 Gbps, and the 10 Gbps Ethernet standard has been used in modern telecommunications structures for several years.
Multimode fiber
In multimode OS, a large number of modes can propagate simultaneously - rays introduced into the light guide at different angles. Multimode OS has a relatively large core diameter (standard values of 50 and 62.5 μm) and, accordingly, a large numerical aperture. The larger diameter of the multimode fiber core simplifies the insertion of optical radiation into the fiber, and the softer tolerance requirements for the multimode fiber reduce the cost of optical transceivers. Thus, multimode fiber prevails in local and home networks of short length.
The main disadvantage of multimode OS is the presence of inter-mode dispersion arising from the fact that different modes travel a different optical path in the fiber. To reduce the effect of this phenomenon, a multimode fiber with a gradient refractive index was developed, due to which the modes in the fiber propagate along parabolic trajectories, and the difference in their optical paths, and, therefore, the inter-mode dispersion is significantly smaller. However, as far as gradient multimode fibers are not balanced, their throughput does not compare with single-mode technologies.
Fiber optic transceivers
To transmit data through optical channels, signals must be converted from electrical to optical, transmitted via a communication line, and then converted back to electrical in the receiver. These conversions take place in a transceiver device that contains electronic units along with optical components.
A time-division multiplexer widely used in transmission technology allows you to increase the transmission rate to 10 Gb/s. Modern high-speed fiber-optic systems offer the following transmission speed standards.
| SONET Standard | SDH Standard | Transmission rate |
|---|---|---|
| OC 1 | - | 51.84 Mb/s |
| OC 3 | STM 1 | 155.52Mbps |
| OC 12 | STM 4 | 622.08 Mb/s |
| OC 48 | STM 16 | 2.4883Gb/s |
| OC 192 | STM 64 | 9.9533 Gb/s |
New multiplex wavelength separation or spectral multiplexing techniques make it possible to increase the data transmission density. multiple multiplex information streams are sent on one fiber channel using transmission of each stream at different wavelengths. The electronic components in the WDM receiver and transmitter are different compared to those used in a time division system.
Application of Fiber Optic Links
Fiber is actively used to build city, regional and federal communication networks, as well as for the arrangement of connecting lines between city PBXs. This is due to the speed, reliability and high throughput of fiber networks. Also, through the use of fiber-optic channels, there are cable television, remote video surveillance, video conferencing and video broadcasting, telemetry and other information systems. In the future, it is planned to use the conversion of speech signals into optical ones in fiber-optic networks.
See also
Links
Notes
- ↑ Feast Your Eyes on the 2023 Submarine Cable Map
- ↑ Operators cut through fibre to Asia
- ↑ Cable stumbling block: interruptions in fiber supply await in the communications market
- ↑ [1] Speed record shattered for data transmission over standard optical fiber 1.53 Petabit per Second Transmission in 55-mode Fiber with Standard Cladding Diameter
- ↑ [2]
- ↑ Japanese scientists set a world record for data transfer speed
- ↑ [3] World Record Transmission of 172 Terabit/s over 2,040 km Distance Coupled-3-core Multi-core Fiber With 319 Tb/s, Japan Absolutely Smashes World Record For Data Transmission Speed
- ↑ [4]
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