What is fiber optic network?
Optical fiber network is a network that is created and works based on optical fiber and its related technologies. Although today the main role of optical fiber is the expansion of international and intercontinental communication highways, it is also used in urban and local networks. On the other hand, the need of world users for high-speed internet and broadband is continuously increasing. And on the other hand, because optical fiber is superior to wireless and satellite connections in terms of bandwidth, data transfer speed, and reliability, it is also attractive to businesses and home users.
Optical fiber in homes
One of the growing types of optical fiber networks is home fiber communication or FTTH (abbreviation of Fiber to the Home), which is also called FTTP (abbreviation of Fiber to the Premises). In the FTTH or FTTP network, optical fiber is stretched from a central point directly to buildings such as houses, apartments, and companies so that users can access high-speed Internet. FTTH network is mostly faster than other current technologies. The speed of data transmission in FTTH is up to 100 Mbps, that is, 20 to 100 times the speed of cable or DSL modems. In places that support this infrastructure, the FTTH speed increases and can reach 330 to 350 Mbps.
Implementing FTTH on a large scale is expensive because it requires fiber optic cabling. For this reason, sometimes FTTC (Fiber to the Curb/Cabinet) networks are used instead of FTTH. In the FTTC network, the optical fiber cable is stretched not to the building itself, but to the cable box in the area of houses and buildings, and copper cable is used from the cable box to the building itself. In other words, in the FTTC network, part of the connection is copper and the other part is fiber optic. Of course, the speed of half-fiber FTTC network is lower than all-fiber FTTH network, but it is faster compared to all-copper cable networks.
Optical fiber in Iran
In 1367, Iran’s first optical fiber production unit was established in Shahid Qandi factory in Yazd. Then, in 1368, the first intercity optical fiber connected Tehran and Karaj in a 54 km long route. After that, the optical fiber network of the country was developed through four other routes of 516 kilometers from Tehran to the surrounding cities.
In continuation of the fiber optic network development process, Iran’s Jask port was connected to Fujairah in the United Arab Emirates with 160 km of optical fiber in 1370 to facilitate international communication between Iran and the countries of the Persian Gulf. One of the parts of Iran’s main optical fiber network is a 2000 km long route that connects our country to Asia and Europe.
Currently, the largest fiber optic service provider to subscribers in Iran is the telecommunications company. Private companies of the country can also enter the fiber optic field. But because optical fiber projects require a lot of capital and on the other hand, they are slow to pay off, the presence of private companies in this field has faced a challenge.
However, optical fiber is still expanding in Iran. In 2018, another unit for the production of optical fiber was launched in the special economic zone of Salafchegan, Qom province. In April 2019, the director general of communications and international affairs of the telecommunications company announced about 90,000 fiber optic subscribers in Iran.
Fiber optic history at a glance
The current position of optical fiber is the result of various efforts and researches. One of the first actions in the history of optical fiber took place in the 1840s when Daniel Coladon, a Swiss physicist, and Jacques Babinet, a French physicist, showed that it was possible to refract light and reflect it (successively) in water (or materials such as glass). directed the light in a certain direction.
In 1870, John Tyndall, an Irish physicist and inventor, demonstrated a similar experiment at the Royal Society in London. He shone the light on a glass container containing water. Then, when he emptied some of the water in the container, the light also bent in line with the direction of the water falling. This phenomenon, i.e. bending of light, is the same thing that happens in optical fiber.
In the 1930s, two German students named Heinrich Lamm and Walter Gerlock tried to make a gastroscope using optical tubes.
In the 1950s, Indian-origin physicist Narinder Kapani and English physicist Harold Hopkins sent a simple image into a light tube consisting of thousands of glass filaments. Kapani then invented the first operational fiber optic cable in 1952.
In 1957, three scientists from the University of Michigan named Lawrence Curtis, Basil Hirschowitz and Wilbur Peters built the first operational gastroscope based on optical fiber.
In 1965, Charles Cao, a physicist of Chinese origin, and his English colleague George Hockman, discovered that the reason for signal attenuation in optical fibers is the low purity of the glass used in them. Kao advised that if high-purity glass was used in fiber optic cables, telephone signals could be transmitted over much longer distances. He won the 2009 Nobel Prize in Physics along with two other scientists for this important discovery.
Over the next two decades, as a result of research, the rate of signal attenuation in optical fiber decreased to such an extent that optical fiber became the most widely used medium for transmitting electronic information. The first fiber optic telephone cable was laid in 1977 between Long Beach and Artesia, California. In 1997, a large fiber optic telephone cable called FLAG (short for Fiber-Optic Link Around Globe) was laid between London and Tokyo.
Today, optical fiber forms the backbone of modern communication infrastructure.
