Fiber optic communication is one of the fastest, most effective, and widely used transmission mediums invented by humanity to date, with over 90% of global information communication being transmitted through fiber optics. Currently, China has become a major manufacturer and user of fiber optic cables. In 2023, China's fiber optic cable production reached 323 million core kilometers, equivalent to circling the Earth over 8,000 times.
This article delves into the history of fiber optic communication, exploring the "light communication" that has traversed the river of history.
The "Light" That Crossed a Millennium
3,000 years ago, light, in the form of "fire" and "brightness," was a practical natural phenomenon that attracted human attention for its ability to provide warmth and illumination. The "Mo Jing" from 450-250 BCE, written by Mozi and his disciples, contains scientific records of light traveling in straight lines, including observations of mirror reflection and pinhole imaging, indicating the budding of optics.
During the Western Zhou period, King You of Zhou lit beacon fires to amuse Baosi, which ultimately led to the downfall of the Western Zhou dynasty. This is considered a classic example of ancient optical communication, where beacon fires were used to transmit information about enemy invasions, capitalizing on the fast transmission of light signals.
The Earliest Concept of Fiber Optics
In 1840, French scientist Daniel Colladon conducted an experiment where he drilled a hole in a water-filled bucket, allowing water to slowly flow out. When light was shone into the water stream, he observed that the light followed the direction of the water flow, bending along its path. This was a phenomenon of light refraction. It wasn't until 1950 that British scientists demonstrated a thickly coated optical fiber that could transmit light, similar to modern fiber optics but with significant attenuation, marking the infancy of fiber optics.
The Dawn of the Fiber Optic Era
The wormhole moment from the laboratory to the industry for fiber optic communication occurred in the 1960s. Engineer and future Nobel Prize laureate Charles Kao published a historically significant paper analyzing the main causes of fiber optic transmission loss. He theoretically proposed that it was possible to reduce the loss to 20dB/km and suggested that such fiber optics could be used for communication.
Guided by this theory, in 1970, Corning Incorporated in the United States produced fiber optics with a loss of 20dB/km, proving the viability of fiber optics as a communication medium. Concurrently, Bell Labs invented semiconductor lasers using gallium arsenide (GaAs) as the material, which, due to their small size, were extensively used in fiber optic communication systems. By 1972, the transmission loss of fiber optics was reduced to 4dB/km, officially ushering in the era of fiber optic communication.
China: The Pursuer
The second fiber optic revolution began in the 1980s, with developed countries commercializing fiber optic communication technology on a large scale. The first was the G3651 multimode fiber, suitable for low transmission rates of 34Mbit/s and light-emitting diodes (LEDs). As transmission rates increased and laser diodes emerged, traditional G.652 single-mode fibers became widely used. In the 1990s, with the widespread application of EDFA and WDM technologies, a new type of non-zero dispersion-shifted single-mode fiber (NZDSSF), or G.655 fiber, was introduced. After nearly two decades of rapid development, the communication rate of fiber optics has increased from 45Mbit/s in 1978 to 40Gbit/s today.
Although China began researching fiber optic communication in the 1970s, the race to catch up with light is still a long journey ahead. In 1988, recognizing the importance of fiber optic communication after accumulating certain scientific research, China began constructing the "Eight Horizontals and Eight Verticals" large-capacity fiber optic communication trunk transmission network. In 1996, the first SDH equipment officially entered the optical transmission network industry, signifying that fiber optic communication in China was no longer just a government-led infrastructure project but a vibrant and diversely developing market track.
From 2006 to the present, communication technology and the internet have undergone a systematic and dramatic evolution. From the budding concept of the Internet of Things (IoT) and the proliferation of mobile devices to the gradual integration of IoT into industry and life, the repeatedly mentioned concept of "everything connected" has presented new demands for communication networks. Furthermore, the transformation towards inclusivity on the business end, with the widespread adoption of industrial intelligence, smart industry, and enterprise cloud services, is embedding fiber optic communication deeper into more enterprises as an indispensable part. Finally, the metamorphosis of communication technology, with the emergence of 5G and the application of the Wi-Fi 6 protocol, signifies humanity's continuous pursuit of the speed of light. As an essential component of the communication bridge, fiber optic communication is also expected to undergo fundamental technological transformations.
Amidst this evolution, we witness the world's desire for technological advancement and a sensitivity to progress that far exceeds our imagination.
Looking back at China's seemingly inconspicuous path of fiber optic communication, we can also see the twinkling stars of innovation.
"Fiber to the Desk"
Currently, with the continuous emergence of new technologies such as GIS, digital twins, BIM, and the metaverse, traditional local area networks can no longer meet the increasingly high demands of various industries for network bandwidth, stability, and low latency. Fiber optic communication is better equipped to handle the immense pressure brought by future massive data and high-speed computing requirements. With the global trend of broadband and optical network city construction, "fiber to the desk" has become the inevitable direction.
Among various broadband access technologies, Passive Optical LAN (POL) technology, with its advantages of large capacity, long transmission distance, lower cost, and full-service support, has become a popular technology and will play a significant role in the future.
Unobstructed Global Networking
The development of the human economy has led to a rapid increase in communication needs, and the wave of new technological revolutions is a major driving force for social progress. In the future of all-fiber networks, under continuous innovation, we will see a future where light connections are ubiquitous.
Humanity has pursued light for a long time, and light has traveled millions of light-years forward.
Yet, when we bring this concept into our daily lives, we find that this "million light-years" distance seems quite short. A century ago, we could only hear the faint sounds brought by light through a thin piece of mica. A century later, we open our phones and computers, and the readily available light in our palms projects the scenery from the other side of the Earth in real time. This journey of chasing light will not end; the pursuers of light will continue to capture the power of light and use it to change the world.
