What is the principle of optical communication?

The principle of optical fiber communication is: at the transmitting end, the transmitted information (such as voice) should be converted into an electrical signal, and then modulated on the laser beam emitted by the laser, so that the intensity of light changes with the amplitude (frequency) of the electrical signal, and then transmitted through the optical fiber; At the receiving end, the detector converts the optical signal into an electrical signal after receiving it, and recovers the original information after demodulation.

Optical fiber communication is the main transmission means of modern communication network. Its development history is only one or two decades, and it has experienced three generations: short wavelength multimode fiber, long wavelength multimode fiber and long wavelength single mode fiber.

The adoption of optical fiber communication is a major change in the history of communication. More than 20 countries, including the United States, Japan, Britain and France, have announced that they will no longer build wired communication lines and are committed to developing optical fiber communication. China optical fiber communication has entered the practical stage.

Extended data:

The key part of optical communication network is equipped with optical transmission equipment. This device plays many roles.

1. signal conversion (signal transmission): convert electrical signals into optical signals.

2. Signal multiplexing: A plurality of narrow signals are converged into a wide signal.

3. Signal relay: long-distance transmission, intermediate signal relay.

4. Signal steering: Change the transmission direction of signals.

5. Signal demultiplexing: the multiplexed signal is decomposed into the original single signal.

6. Signal conversion (receiving signal): converting optical signals into electrical signals.

Optical communication equipment includes optical fiber, G.657 optical fiber for FTTx, G.656 optical fiber for broadband long-distance high-speed large-capacity optical fiber transmission, photonic crystal fiber, and rare earth-doped optical fiber (including ytterbium-doped fiber, erbium-doped fiber, thulium-doped fiber, etc.). ), laser energy transmission fiber, and new optical fiber with some special properties, including plastic optical fiber and polymer optical fiber.

Optical fiber access equipment, passive optical network (PON), optical line terminal (OLT), optical network unit (ONU), wavelength division multiplexer, etc.

References:

Baidu encyclopedia-optical communication