how does fiber optic internet work

No matter whether it is high-resolution video, online gaming, or teleworking, it is inseparable from the support of fiber optic. But have you ever wondered how the fiber optic Internet works? How light signals are generated, tranSMitted, and finally used by us? This article will take you step by step to uncover the technical mysteries behind the fiber optic Internet.

The birth of the optical signal: the amazing transformation from electricity to light

The first step in the fiber optic Internet is to convert electrical signals into optical signals. This process is done by optical transmitters, and its core components are laser diodes or Light Emitting Diodes (LEDs).

• laser diodeWhen current passes through a laser diode, electrons and holes in the semiconductor material recombine to generate stimulated radiation, forming a highly concentrated laser beam. This laser has good coherence and can carry information efficiently.

• Light Emitting Diode (LED): Unlike laser diodes, LEDs generate light by spontaneous emission. Although its optical signal coherence is poor, it is cheaper and suitable for some scenarios that do not require high performance.

Whether it is the light produced by lasers or LEDs, they have become the "carrier" of information, converting data into the form of light, ready to start a high-speed journey in the optical fiber.

The structure of optical fiber: the "highway" of optical signals

The smooth transmission of optical signals requires the support of optical fibers. The structure of optical fibers seems simple, but it contains a delicate design. It is mainly composed of three parts:

1. coreThis is the core of an optical fiber, made of high-purity silica. The light signal travels in the core, just like a car on a highway.

2. claddingThe material wrapped in the outer layer of the core has a lower refractive index than the core. This difference in refractive index causes the light signal to be completely reflected at the junction of the core and the cladding, thus being "trapped" in the core to avoid signal leakage.

3. coating layerThe outermost layer of protective material is used to protect the optical fiber from physical damage or chemical corrosion, ensuring the stability of optical signal transmission.

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It is this delicate structural design that allows optical signals to be efficiently transmitted in optical fibers with little to no external interference.

Transmission of Optical Signals: Total Reflection and Wavelength Division Multiplexing

When the optical signal enters the fiber, it will continue to move through the core in a total reflection manner. Due to the extremely low loss of the fiber, the optical signal can be transmitted for tens or even hundreds of kilometers without relay. But in practical applications, to ensure that the signal can reach farther places, engineers will set up along the way光中继器。这些设备能够对衰减或变形的光信号进行放大和修复，就像给信号“加油”一样，让它继续前行。

In addition, in order to make full use of the transmission capacity of optical fiber, modern optical networks also use波分复用技术（WDM）。这项技术允许一根光纤同时传输多个不同波长的光信号，每个波长都可以承载独立的数据流。这就好比在一条高速公路上开辟了多条车道，让更多的“车辆”（数据）同时通行，极大地提升了光纤的传输效率。

Receiving and converting optical signals: from light back to electricity

After a long journey, the light signal finally arrives at the receiving end. At this time,光接收机开始发挥作用。它的核心部件是光探测器，常见的有光电二极管等。

• The photodetector can convert the light signal into an electric current, the intensity of which is proportional to the intensity of the light signal.

• Then, through a series of signal processing circuits, the current is converted into an electrical signal that can be recognized by devices such as computers, such as digital signals.

At this point, the optical signal has fulfilled its mission, passing information to the end point device, allowing us to browse a web, watch a video, or make a video call smoothly.

summarize

The working principle of fiber optic Internet may seem complicated, but it can be summarized as four steps: the generation of optical signals, the transmission in the fiber optic, the amplification and repair of the signal, and the final reception and conversion. It is the synergy of these technologies that allows us to enjoy high-speed and stable network connections.

I hope that through this article, you can gain a deeper understanding of the technology behind fiber optic Internet. Next time you open a high-resolution video or have a smooth video conference, think about it, there is a beam of light behind it silently "running" for you!