Since what is actually transmitted in the wires is electromagnetic waves, why not use optical fibers to transmit electromagnetic waves? At least there is no electromagnetic wave in the wires...

EEW2018

Since what is actually transmitted in the wires is electromagnetic waves, why not use optical fibers to transmit electromagnetic waves? At least there is no electromagnetic wave in the wires... [Copy link]

Since what is actually transmitted in the wires is electromagnetic waves, why not use optical fibers to transmit electromagnetic waves? At least there is no energy loss caused by resistance in the wires.

btty038

There is a difference between optical fiber and wire. The electromagnetic wave energy, that is, the current signal, is very large and can be large or small. The optical signal of optical fiber is a weak signal.

EEW2018

btty038 posted on 2019-9-9 15:44 There is a difference between optical fiber and wire. The energy of electromagnetic waves, that is, the current signal, is very large and can be large or small. The optical signal of optical fiber is a weak signal

Thank you very much. Electric current is the flow of electrons. The flow speed of electrons is very, very slow compared to the speed of light. Or the flow of electrons is not the propagation flow of electromagnetic waves.

btty038

EEW2018 posted on 2019-9-9 16:26 Thank you very much. Electric current is the flow of electrons. The flow speed of electrons is very, very slow compared to the speed of light. Or the flow of electrons is not electromagnetic...

29447945

It mainly depends on the application scenario. Let's take the simplest example. If a 0 or 1 signal is transmitted through an electric wire, the high and low levels can be directly read by the computer. However, if it is an optical fiber, a device that converts the optical signal into a level signal must be added. Just like when testing, I may be able to use it directly by connecting it to a wire, but it will not work if I only connect one optical fiber.

maychang

It is electromagnetic waves that propagate in optical fibers, but the wavelength of the electromagnetic waves propagating in optical fibers is relatively short.

Optical fiber also has losses, and the losses are not much less than those in wires.

maychang

EEW2018 posted on 2019-9-9 16:26 Thank you very much. Electric current is the flow of electrons. The flow speed of electrons is very, very slow compared to the speed of light. Or the flow of electrons is not electromagnetic...

When you turn on the faucet, water will flow out immediately. The water that flows out of the faucet immediately does not flow from the water plant through the pipe to your home. When you turn on the faucet, the water flows along the water in the pipe. The water starts to flow at a certain point in the pipe. The speed of water flow is the speed of sound in water. As for the water flowing out of the water plant, it may not reach your home until tomorrow.

EEW2018

maychang published on 2019-9-9 17:39 It is electromagnetic waves that propagate in optical fibers, but the wavelength of electromagnetic waves propagating in optical fibers is shorter. Optical fibers also have losses, and they are not as good as those in wires...

Transmitting the same signal over the same distance, the loss of wires is more than ten times that of optical fibers.

maychang

EEW2018 Published on 2019-9-10 07:36 Transmitting the same signal over the same distance, the loss of wires is more than ten times that of optical fibers

Transmissions of different frequencies and powers cannot be directly compared.

Can you compare the power transmission of 50Hz, 500kV transmission lines with that of optical fibers?

qwqwqw2088

Problems with optical and electrical signals

In the 1990s, the city trunk lines of the telecommunications bureau were still coaxial cables, which were electrical signals.

The current information processing is completed in the field of electrical signals. In optical fiber communication, electrical signals must be converted into optical signals so that they can be transmitted on optical fibers.