As early as the beginning of the18th century, a worker inadvertently observed that the water in the water pipe can guide light. Not long after, a Greek worker discovered that light can not only spread quickly from one end of a thin glass rod to the other, but also never spread to the space outside the rod, just like water flowing in a water pipe. Although people have discovered the phenomenon of light guide for a long time, there is no high-quality coherent light source and low-loss glass fiber material, so people just use ordinary glass fiber and ordinary light to demonstrate and test the total reflection and refraction of light.

1960 After the appearance of laser, Charles Kao, a 33-year-old British Chinese scientist who just graduated from London University in 1966, published a paper entitled "Insulated dielectric fiber surface waveguide suitable for optical frequency", and put forward the theory that glass fiber with very low optical transmission loss can be obtained by solving the purity and composition of glass for the first time. According to this theory, in 1970, corning company first proposed the idea of optical fiber with light consumption of 20 dB/km, and the field of optical fiber research and production gradually became active. By the 1980s, optical fiber technology had formed a considerable industry and reached the practical stage.

The so-called "optical fiber" is actually a kind of glass fiber filament thinner than hair filament, with a cylindrical structure, a fiber core with a diameter of 8 microns or 50 microns in the middle, and a sheath matching the refractive index of the fiber core to ensure total reflection in the optical fiber. Then coated with plastic sheath, the outer diameter is generally 125 micron. It can be composed of multiple strands like ordinary metal wires. At present, one optical cable can connect tens of thousands of telephones or dozens of color TV programs, such as 144 core optical cable in the United States.

Compared with the laser atmospheric communication machine, the communication machine for optical fiber communication cancels the aiming system except the coding modulation system. The transmitting and receiving antennas are also simplified as integrated couplers, which are directly coupled to the optical cable through the laser communication machine. In addition, optical relay amplifier is also indispensable in long-distance transmission.

Although the development of laser optical fiber communication is late, it has become the pillar of modern communication field and is becoming more and more prosperous due to the huge market promotion. As early as 1988, the United States successfully laid 32,000 lines of TAT-8 submarine optical cable communication project with two-way telephone capacity across the Atlantic Ocean. Japan's Economic Planning Agency's "20 10 Technology Research and Prediction Research Association" reported on July 819910 that it is required to put the ultra-high density and ultra-high speed "terabyte optical communication system" into practice around 20 10, which is very important for transmitting color images.

Coupled with terabit optical communication systems and related technologies, such as optical fibers, storage components, optical computer components and machines, it will generate a huge market of more than 654.38 billion yen and become the pillar of Japan's high-tech industry.

In Europe, at the end of the 20th century, the optical fiber market was also very active. In the shadow of the continuous economic recession, it outshines others, with an annual transaction volume of 199 1 of1/billion dollars. It is estimated that 1995 will reach $2.3 billion, with an average annual growth rate of 17%.

Entrepreneurs engaged in international communication, led by International Digital Communication Corporation and International Telegraph Corporation, signed the Agreement on the Construction and Maintenance of Submarine Optical Cable APC Connecting Japan and Singapore in Britain on August 6th, 199 1, and started construction. It is estimated that 38 companies from 23 countries and regions will become co-owners of the cable, and it will be delivered at the end of July 1993. Became the first long-distance optical cable extending from Japan to Southeast Asia.

According to the report of Sankei Shimbun199265438+February 2 1, the transmission of 8397 kilometers of high-definition images and digital images has been a complete success, from Pacific Telecom in Petran on the west coast of the United States to San Pu Telegraph Bureau of Japan International Digital Communication.

Starting from 1987, an optical fiber channel with a length of 1.8 km was laid between two local telephone branches in Shanghai for the first time in China, and the total length of the completed optical cable has exceeded 5000 km.

1992 14 February 14, China's Ministry of Posts and Telecommunications, Japan International Telephone and Telegraph Corporation and American Telephone and Telegraph Corporation reached an agreement in Beijing on the construction and maintenance of two submarine optical cables with a total length of 1250 km, 560 megabits and 7560 loops from Nanhui, China. It is estimated that/kloc- This will be the first submarine optical cable in China to connect with foreign countries.

On June 24th, 2008, the optical fiber trunk line along the south coast of China was opened +0992+ 165438, which improved the long-distance communication capacity 10 times. This trunk line is 2,800 kilometers long, with a capacity of over 654.38+0,000 rings and an investment of 450 million yuan. Connecting 72 cities through 1 cities in Jiangsu, Shanghai, Zhejiang, Fujian and Guangdong will play a great role in the reform and opening up.

According to the introduction of relevant departments, during the Eighth Five-Year Plan period, China will build seven optical fiber trunk lines, including Beijing-Jinan-Nanjing, Beijing-Shenyang-Harbin, Xuzhou-Zhengzhou, Zhengzhou -Xi 'an-Chengdu, Hangzhou-Fuzhou-Guizhou-Chengdu, Beijing-Wuhan-Guangzhou and Xi 'an-Lanzhou-Urumqi, with a total length of 32,000 kilometers, and the total investment will exceed. By then, the motherland will form a complete optical cable trunk network, completely changing the status quo of communication congestion.

Optical fiber communication is also widely used in the military. At present, the US Air Force Logistics Command has laid the world's largest optical fiber communication network in eight air bases, and each base has at least 8,000 main computers, terminals and other equipment connected to the network. On 1986, the US military officially opened the military optical cable market. In just over a year, Fibre Channel125,000 km has been laid, and the application scale and development speed have amazed the communication industry.