All you see is wi-fi, but all you see is fiber-optic communication

So, why is the transmission speed of fiber-optic communication so fast? What is fiber communication? What are its advantages and shortcomings compared to other means of communication? In which areas is the technology currently used?

Transmitting information with light in fiberglass.

As a wired network, fiber-optic communication cannot meet the needs of mobile. In daily life, our mobile communication uses wireless networks, and the presence of optical communication does not seem to be strong.

“But in reality, more than 90% of the information is transmitted via fiber optics.The mobile phone is connected to the base station via a wireless network, and the transmission of signals between the base stations mostly depends on the optical fiber.”He Zhixue, deputy director of the Optical System Research Office of the State Key Laboratory of Optical Fiber Communication Network Technology, said in an interview with the Science and Technology Daily.

Optical fiber is an optical fiber that is as thin as a hair, can be buried directly, overhead, or placed on the sea floor.Because of its light weight, convenience, and low cost of producing raw materials, it eventually replaced the bulky cable as the mainstream signal transmission medium.

To put it simply, optical fiber communication is the common application of optical communication, such as telescope traffic lights, etc., they use the atmosphere to spread visible light, belongs to the visual transmission optical communication is the use of glass fiber in the light transmission information.

An optical communications practitioner told sci-tech daily that optical signals decay less during transmission than electrical signals. He explained that, for example, an optical signal decays from 1 to 0.99 after 100 kilometers, while an electrical signal decays from 1 to 0.5 after only 1 kilometer.

From the point of view of principle, the basic material elements that constitute the optical fiber communication are optical fiber light source and optical detector.

Large capacity and long-distance transmission capability

According to reports, the ultimate method of fiber-optic broadband access is fiber-to-the-home, that is, directly connecting the fiber to the place required by the user, so that it can obtain a large amount of information by using the fiber.

“The wireless communication method is susceptible to electromagnetic interference, and the cable transmission method is costly to lay. In contrast, optical fiber communication has the advantages of large capacity, long-distance transmission capability, good confidentiality, and strong adaptability. Moreover, the fiber is small in size and easy to use. Construction and maintenance, raw material prices are also relatively low.” He Zhixue said.

Although fiber-optic communication has the above advantages, its own short board cannot be ignored. For example, the fiber is brittle and easily broken. In addition, the cutting or connecting of the fiber requires the use of a specific device. It should be noted that urban construction or natural disasters can easily cause fiber line failures.

In practical applications, the realization of optical fiber transmission mainly depends on the optical transmitting end machine and the optical receiving end machine. The optical transmitting end device can effectively adjust and convert the electro-optical signal, thereby converting the electrical signal into an optical signal carried by the optical fiber. The optical receiving end performs reverse conversion and can also demodulate the electrical signal.The optical receiving end and the optical transmitting end are connected by a connector to an optical cable to realize transmission, transmission, reception and display of information.

Related high-end manufacturing equipment relies on imports

Commonly used optical fibers are mainly standard single-mode optical fibers. In theory, the information transmission speed per unit time is about 140 Tbit/s. If the speed of transmitting information reaches this limit, it will cause information congestion. Single mode fiber is usually a fiber that can only transmit one mode.

At present, standard single-mode optical fiber communication is one of the communication methods commonly used by operators. The transmission capacity of this mode is 16 Tbit/s, which has not yet reached the theoretical limit value. “The new record of 1.06Pbit/s, which was printed at the beginning of this year, is the result of breakthroughs in single-mode fiber-optic communication technology, but such speed is difficult to achieve in commercial use in a short period of time.” He Zhixue said.

Technically, compared with single-mode, multi-core fiber transmission mode has greater advantages in achieving high speed, but this mode is still at the forefront, and further breakthroughs are needed in core technologies, key components, and hardware devices. .

After 5 to 10 years, under the impetus of application requirements, the key technologies of 1.06Pbit/s ultra-large capacity single-mode multi-core optical fiber transmission system may be first applied to some special scenarios, such as transoceanic transmission and some large-scale Data center.” He Zhixue said.

At present, China’s optical communication technology can compete with the international advanced level, but still faces many difficulties. For example, the relevant industrial base is weak, lacking originality and autonomy technology, and insufficient fiber optic raw materials. “At present, the high-end equipment needed to manufacture fiber materials such as wire drawing and fiber winding is dependent on imports.” He Zhixue said.

At the same time, high-end devices and chips related to optical fiber communication are mainly controlled by developed countries such as the United States and Japan.

In this regard, He Zhixue suggested that it is necessary to strengthen relevant basic theoretical research, do a good job of the long-term layout of core technologies, predict the development trend of technology, and jump out of the technical iteration cycle of “tracking-lag-re-tracking-and backwardness”.

In addition, He Zhixue emphasized that it is necessary to increase investment in research and development, design and processing of high-end chips and high-end devices, stimulate the enthusiasm of R&D talents, and focus on protecting original achievements. “Especially, we must do a top-level design, achieve synergy and innovation in manpower, infrastructure, and policies, and improve the supporting capabilities of the corresponding industries,” he said.