In what form does a laser propagate forward in an optical fiber?

What characteristics of the laser is used in the optical fiber, the rubber is used to transmit information in the optical fiber, because the frequency of the laser is very high, and it can transmit much coarser information in the same time. ”

Optical fibers use lasers to transmit information.

Optical fiber communication technology (opticalfibercommunications) stands out from optical communication and has become one of the main pillars of modern telecommunication communication, playing a pivotal role in modern telecommunication networks. As an emerging technology, optical fiber communication is rare in the history of communication for its rapid development and wide application in recent years, and it is also an important symbol of the world's new technological revolution and the main transmission tool of various information in the future information society.

Optical fiber is the abbreviation of optical fiber. Optical fiber communication is a communication method that uses light waves as the information carrier and optical fiber as the transmission medium. In principle, the basic material elements that make up optical fiber communication are optical fibers, light sources, and optical detectors.

In addition to the classification of optical fibers according to the manufacturing process, material composition and optical properties, in applications, optical fibers are often classified according to their uses, which can be divided into optical fibers for communication and optical fibers for sensing. The transmission medium optical fiber is divided into two types: general and special, and the functional device optical fiber refers to the optical fiber used to complete the functions of light wave amplification, shaping, frequency division, frequency doubling, modulation and optical oscillation, and is often modified in the form of a functional device.

Light travels in a (total reflection) manner in an optical fiber.

**Very clear description of the problem. If it is refraction, the light will not run out of the optical fibers into the air.

Light travels in a (total reflection) manner in an optical fiber.

Refraction of light: When light is obliquely emitted from one transparent medium into another, the direction of propagation generally changes, which is called refraction of light. Understand:

The refraction of light and the reflection of light occur at the junction of the two mediums, but the reflected light returns to the original medium, and the refracted light enters the other medium, because the light travels at different speeds in two different substances, so the direction of propagation changes at the junction of the two media, which is the refraction of lightNote: at the junction of the two media, both refraction and reflection occur. The speed of light of reflected light is the same as that of incident light, and the speed of light of refracted light is different from that of incident light.

The reason why laser is widely used in optical fiber communication: because laser has the characteristics of good directionality, high brightness, good monochromacy, and good coherence.

If ordinary light is used, due to poor directionality, the divergence angle is too large, and it is impossible to advance through total reflection along a specific path in the optical fiber. In addition, ordinary light has poor monochromaticity, and even if it is a color of light, it actually contains many frequencies of light, and when such light propagates in an optical fiber, it cannot travel a long distance due to the dispersion of light. Therefore, fiber optic communication must use lasers.

A laser is a strong beam with good monochromatic, coherent and highly collimated. Compared to other light sources, the wavelength of the laser is very concentrated, and the photons that make up the laser beam have a fixed phase relationship. Light from lasers can travel long distances with little attenuation; The laser can also be focused into a very small dot that is brighter than the sun.

Because of these properties, lasers are widely used in a wide range of industries.

Features of lasers:

1. High brightness.

The energy of the laser is highly concentrated in the narrow beam, so the brightness of the laser is usually very high, the laser is hundreds of millions of times stronger than the light emitted by ordinary light sources, and the brightness of the laser is even higher than the brightness of the sun's surface light.

2. Good directionality.

The divergence angle of a laser is very small, and the laser can still remain non-divergent after traveling a long distance, whereas the divergence of ordinary radio waves is usually very high. Studies have shown that when the laser travels 20 km, the spot diameter is only 20 30 cm. As a result, astronauts can use lasers to communicate in space.

3. Good monochromaticity.

The color of light is determined by the wavelength of the light. When light with different wavelengths acts on the human visual system, it causes different cells to produce nerve impulses, causing the person to perceive different colors. In a laser beam, the wavelength of all photons is basically the same, the spectral line width of the laser is very narrow, the color of the laser is pure, and the monochromacy is very good.

4. Good coherence.

Lasers are composed of a series of photons of the same wavelength and the same direction of propagation, and the coherence of lasers is very good and the energy is very high, so people can use denier and lasers to transmit information [4].

The reason why fiber optic communication takes advantage of the good coherence of laser is that; Good coherence means that the same laser produces a single laser frequency. That is, the frequency range of the laser emitted by each laser is very narrow, which can ensure that one fiber can accommodate the laser generated by a large number of lasers, increasing the communication capacity.

Hello, fiber optic communication is the product of the combination of laser and optical fiber, which takes advantage of the characteristics of laser frequency unity.

It is best to choose high-quality ones related to total reflection optical fiber and cable, and we generally use Phoenix's on the construction site.

The laser is continuously emitted in the optical fiber and propagates forward, that is, the propagation principle of the laser in the optical fiber is the reflection of light;

Therefore, choose B

a. The wire used in optical fiber communication is an optical fiber, not a metal wire, so A is wrong;

b. The light propagates forward after multiple reflections in the optical fiber mold bucket dimension, so B is wrong;

c. Optical fiber communication has the advantages of large amount of transmitted information and small light energy loss, so C is correct; Stool brother.

d. The optical signal propagates at the speed of light in the optical fiber, so D is wrong and C is chosen