Brief History of optical fiber communication development

Along with the social progress and development, as well as people's growing material and cultural needs, communication to large capacity, long-distance direction of development has been an inevitable trend of development. Since the light wave has a very high frequency (about 300 million MHz), that is, it has a very high bandwidth to accommodate huge communication information, so the use of optical waves as a carrier for communication has been the goal of people for more than hundreds of years to pursue.

1, optical fiber communication milestones

In the 60 's, although people have painstakingly studied the aperture waveguide, gas lens waveguide, hollow metal waveguide, and so on, want to use them as the transmission of light waves of the media to achieve communication, but eventually because they are too large or expensive failure to be practical. That is to say, after hundreds of years, people have never found the ideal transmission medium for transmitting light waves.

In July 1966, the British and Chinese scholar Dr. Charles Kao (K.c.kao) published in Piee magazine a very famous article "Optical fiber surface waveguide for optical frequency", this paper theoretically proves the possibility of using optical fiber as transmission medium to realize optical communication. The waveguide junction (ie step fiber) for communication fiber is designed. It is more important to make a scientific statement of the possibility of manufacturing ultra low consumption fiber for communication, that is, strengthening raw material purification, adding appropriate doping agent, can reduce the attenuation coefficient of optical fiber to below 20db/km. At that time, the world can only be manufactured for industrial, medical fiber, its decline in 1000db/km above. It is considered to be impossible to manufacture optical fibers below the 20db/km. The subsequent developments eloquently demonstrate the correctness of the theoretical and scientific boldness of Dr. Charles Kao's article, so the article is hailed as a milestone in optical fiber communication.

2, Fuse

1970 Corning Glass Company in accordance with the concept of Charles Kao, modified chemical facies deposition method (MCVD method) to create the world's first ultra-low-consumption fiber, the optical fiber communication explosive development of the fuse.

While the optical fiber produced by Corning Glass was only a few meters long, it consumed about 20db/km and was damaged a few hours later. But it proved, after all, that the use of the technology and technology at that time to manufacture the ultra low consumption optical fiber for communication is entirely possible, that is, to find the ideal transmission medium for low-power transmission of light, which is a major breakthrough in optical communication research.

3. Explosive development

Since 1970, the world's developed countries to the study of optical fiber communications poured a lot of manpower and material resources, its oncoming force, the scale of the speed of the rapid far beyond the people's expectations, so that the optical fiber communication technology has made extremely amazing progress.

From the loss of optical fiber to see:

Seven o year: 20db/km

72:4 db/km

74:1.1db/km

76:0.5db/km

79:0.2db/km

Ninth O Year: 0.14db/km

It is close to the theoretical decay limit value 0.1db/km of quartz fiber.

See from optical Devices:

In 197, Bell Laboratories in the United States developed the world's first GaAs semiconductor laser with continuous wave working at room temperature, and found suitable light source devices for optical fiber communication. It was gradually developed to a better performance, a tens of thousands of-hour long life of the heterogeneous knot-type laser and now distributed feedback Single longitudinal mode lasers (DFB) and multiple quantum well lasers (MQW). Optical receiving devices also develop from simple silicon pin diodes to the Ⅲ-ⅴ avalanche diode APD, which has a quantum efficiency of up to 90%.

Viewed from optical fiber communication systems:

It is the rapid development of optical fiber manufacturing technology and optoelectronic device manufacturing technology, the development of large-scale, VLSI technology and microprocessor technology has driven the rapid development of optical fiber communication system from small to large capacity, from short distance to long distance, from low to high level, from old system (PDH) to new System (SDH).

In the 76, the United States opened the world's first practical optical fiber communication system in Atlanta. The rate is 45mb/s and the relay distance is km. In 80, multimode optical fiber Communication System (140MB/S) was commercialized, and the field test of Single-mode optical fiber communication system was set up.

In the 90, Single-mode optical fiber communication system entered the commercial stage (565MB/S), and started the field test of 0 dispersion shifted fiber and wavelength division multiplexing and coherent communication, and set up the technical standard of the digital synchronization system (SDH) successively.

In the 93, SDH products began to be commercialized (622mb/s below).

In the 95, 2.5GB/S SDH products entered the commercial stage.

In the 96, 10gb/s SDH Products entered the commercial stage.

In the 97, a major breakthrough was made in the SDH product test of 20gb/s and 40gb/s using Wavelength Division multiplexing (WDM) technology.

In addition, great progress is being made in optical soliton communication, ultra long wavelength communication and coherent optical communication.

In short, from 1970 to now although only a short period of less than 30 years, but optical fiber communication technology has made tremendous progress. With extremely wide bandwidth of light wave as the carrier of information transmission to achieve communication, this century, the dream of the people have become a living reality today. However, in the current optical fiber communication, its actual application is only about 2% of its potential capacity, there is still huge potential for people to develop and utilize. Therefore, optical fiber communication technology is not stagnant, but to a higher level, higher stage direction.