Professional Overview Of Fiber Optic Communication

In 1966, British Chinese Charles Kao published a paper proposing the use of quartz to make glass fiber (optical fiber), which had a loss of up to 20dB/km and could achieve high-capacity optical fiber communication. At that time, only a few people in the world believed in leaders such as the Standard Telecommunications Laboratory (STL) in the UK, Corning Glass Company in the US, Bell Laboratories, and others. In 2009, Gao Kun won the Nobel Prize for inventing optical fiber. In 1970, Corning developed a quartz fiber optic cable with a loss as low as 20dB/km and a length of approximately 30m. In 1976, Bell Laboratories established an experimental line in Atlanta, Washington with a transmission rate of only 45Mb/s, which could only transmit hundreds of telephones, while using coaxial cables could transmit 1800 telephones. Because at that time there were no communication lasers available, and instead light emitting diodes (LEDs) were used as the light source for fiber optic communication, the speed was very low. Around 1984, semiconductor lasers for communication were successfully developed, and the speed of fiber optic communication reached 144Mb/s, capable of transmitting 1920 telephone lines. In 1992, the transmission rate of a single fiber optic cable reached 2.5Gb/s, equivalent to over 30000 telephone lines. In 1996, lasers of various wavelengths were successfully developed, enabling multi wavelength and multi-channel fiber optic communication, known as "wavelength division multiplexing" (WDM) technology, which transmits multiple optical signals of different wavelengths within one fiber optic cable. So the transmission capacity of fiber optic communication doubled. In 2000, using WDM technology, the transmission rate of a single optical fiber reached 640Gb/s. Some people have great doubts about the fact that Gao Kun invented optical fiber in 1976 and only won the Nobel Prize in 2010. In fact, from the development history of optical fibers mentioned above, it can be seen that despite the large capacity of optical fibers, they cannot fully utilize their ultra large capacity without high-speed lasers and microelectronics. The speed of electronic devices has only reached the level of gigabits per second, and the emergence of high-speed lasers of various wavelengths has enabled fiber optic transmission to reach the level of terabits per second (1Tb/s=1000 Gb/s), which has led people to realize that "the invention of fiber optic has sparked a revolution in communication technology.