Misunderstanding about faster transmission speed of optical fiber than copper wire

I have read a lot of interpretations about this item, especially when Baidu knows that many of them are nonsense, but I cannot read it, so I wrote an article, for you to have a clear understanding of the aspect.

1. Is the optical fiber transmission speed faster than that of copper wires in terms of transmission speed?

As we all know, copper wires are what we call cables, transmitting electrical signals, while optical fibers transmit optical signals. Therefore, there are two network access methods: cable access and optical fiber access.

Let's take a look at the transmission speed of the two media: the electrical signal transmission speed in the copper wire is about 2.3*10 (8 power) m/s, the optical signal propagation speed is 2.0x10 (8 power) m/s.

Right. You are not mistaken. Theoretically, the optical fiber transmission speed is not as fast as that of copper wires.

2. Why is the copper wire spreading faster?

According to modern physics, the propagation speed of all electromagnetic waves (including visible light) in vacuum is constant, that is, the speed of light, 3x10 (8 power) m/s.

Why is the propagation speed lower in the optical fiber? In fact, the principle is very simple. The optical fiber transmission principle should be clear to everyone. It uses the total reflection of light. Therefore, the optical fiber transmission method is as follows,

The actual distance is greater than the length of the optical fiber, so the speed is lower than the electrical signal transmission speed of the copper wire.

3. Why is the speed of Optical Fiber better?

The following points can be explained:

1,Transmission Distance:

We mentioned above that copper wires are faster to spread, but they cannot be ignored. That is, the propagation distance problem. One factor in the propagation distance problem is "attenuation ".

For example, if we use twisted pair wires, the propagation distance can reach 100 m, and a longer distance needs to be sustained by a repeater,

In addition, only a limited number of relays can be used, and each relay consumes time.

The Optical Transmission Loss in optical fiber is much lower than the loss in the wire. The propagation distance is generally several kilometers or more.

In summary, the optical fiber is faster.

2,Cost

Although the cost of optical fiber is high, the cost of optical fiber is gradually decreasing due to the continuous technological innovation.

More importantly, people are increasingly demanding on network speed, from the initial several Mbps of bandwidth to the current hundred Gbit/s of bandwidth spanning the ocean, and the future of several thousand Gbit/s of bandwidth.

3,Degree of Parallelism

Do you still remember copper cables that are thicker than your arm? (It is also the target of thieves) the thick cables are actually composed of thousands or even hundreds of copper wires.

Optical fiber, which also contains several small glass wires.

The purpose of this operation is to increase the concurrency of the data transmission media, which can also be called "width ". Just like in a 32-bit computer bus, 32-bit data can be transmitted at a unified time.

1000 pieces of glass wire, and 1000 pieces of copper wire, is the difference between the wrist and thigh, which is convenient not to mention.

4,Others

You steal copper wires and are afraid of being sentenced. You can melt them and sell them again. I have not heard of selling glass wire.

Now, let's get to know the door.

More importantly, the signal transmission speed is one aspect. In fact, more importantly, the signal reception capability:

If the receiving capability is insufficient, the sending capability cannot be improved.

(PS: the data transmission control mechanism in the data link layer determines the transmission speed based on the recipient's receiving capability .)

(Author: Fresh [email protected])