What are the types of optical fibers? There are several types of optical fibers

Two kinds, single-mode fiber and multimode fiber.

1. According to the material classification of optical fibers, optical fibers can be divided into quartz optical fibers and all-plastic optical fibers.

Quartz optical fiber generally refers to an optical fiber composed of a doped quartz core and a doped quartz cladding. These fibers have very low losses and moderate dispersion. At present, the vast majority of optical fibers for communication are quartz optical fibers;

All-plastic optical fiber is a new type of optical fiber for communication, which has the characteristics of large loss, thick core (diameter 100 600 m), large numerical aperture (Na) and low manufacturing cost. All-plastic fibers are suitable for shorter length applications, such as in-house computer networking and in-ship communications.

2. According to the classification of the refractive index distribution of the optical fiber profile, the optical fiber can be divided into step optical fiber and gradual optical fiber.

3. According to the number of modes of optical fiber transmission, optical fibers can be divided into multi-mode optical fibers and single-mode optical fibers.

Single-mode fiber is an optical fiber that can transmit only one mode. Single-mode fiber can only transmit the fundamental mode (the lowest order mode), there is no delay difference between the modes, and it has a much larger bandwidth than multimode fiber. Single-mode fibers have a mode field diameter of only a few micrometers (m) and their bandwidth is typically one or two orders of magnitude higher than that of gradient multimode fibers.

Therefore, it is suitable for high-capacity, long-distance communication.

4. According to the classification stipulated in the international standard (according to the ITU-T recommendation), the types of optical fibers can be divided into optical fibers (50 125 m multimode graded refractive index fibers), optical fibers (non-dispersion shift fibers), optical fibers (dispersion shift optical fibers DSF), optical fibers (cut-off wavelength displacement optical fibers), optical fibers (non-zero dispersion displacement optical fibers).

5. According to the classification of IEC standards, IEC standards divide the types of optical fibers into Class A multi-mode optical fibers and Class B single-mode optical fibers.

Class A multimode fibers include A1A multimode fibers (50 125 m type multimode fibers), A1B multimode fibers (type multimode fibers), and A1D multimode fibers (100 140 m type multimode fibers).

Class B single-mode fibers include fibers corresponding to G652 fibers, G654 fibers, B2 fibers corresponding to fibers, and B4 fibers corresponding to fibers.

a.According to the transmission mode of light in the optical fiber, it can be divided into: single-touch fiber and multi-mode fiber.

Multimode fiber: the center glass core is thicker (50 or, can transmit multiple modes of light. However, the intermodal dispersion is large, which limits the frequency at which the digital signal can be transmitted, and it becomes more severe with distance.

For example, a 600 km fiber will only have 300 MB of bandwidth at 2 km. Therefore, the distance of multimode fiber transmission is relatively close, generally only a few kilometers.

Single-mode fiber: The center glass core is thin (generally 9 or 10 m in diameter) and can only transmit one mode of light. Therefore, its inter-mode dispersion is very small, which is suitable for long-distance communication, but its chromatic dispersion plays a major role, so that the single-mode fiber has higher requirements for the spectral width and stability of the light source, that is, the spectral width should be narrow and the stability should be good.

b.According to the optimal transmission frequency window, it is divided into conventional single-mode fiber and dispersion-shifted single-mode fiber.

Conventional type: Optical fiber manufacturers optimize the optical fiber transmission frequency to a single wavelength of light, such as 1300nm.

Dispersion Shift Type: The fiber production family optimizes the optical fiber transmission frequency on two wavelengths of light, such as 1300nm and 1550nm.

c.According to the refractive index distribution: mutated and gradual fibers.

Optical fiber access networks can be technically divided into two categories: active optical networks and passive optical networks.

1.Active optical networks can be divided into SDH-based AON and PDH-based AON.

2.Passive optical networks can be divided into narrowband PON and wideband PON.

There are various types of optical fibers, and here are some of the common ones:

Single mode fiber: A single mode fiber is an optical fiber that transmits only a single photon mode. It has a small core diameter, typically 8 10 microns, and uses a laser as a light source.

Single-mode fiber is suitable for long-distance, high-speed, and wideband communication transmission because it has low signal attenuation and small bandwidth limitations.

Multimode fiber: Multimode fiber has a large core diameter, typically 50 100 microns, and uses LEDs as a light source. Multimode fibers allow multiple photonic modes to be transmitted, so they have a large bandwidth and are suitable for short-distance, high-speed, and wideband communication transmissions.

Plastic optical fiber: Plastic optical fiber is an optical fiber made of plastic, which is usually used for short-distance, low-speed, and low-cost communication transmission. It is less costly, easy to install and bend, but has a shorter transmission distance and higher signal attenuation.

Quartz optical fiber: Quartz optical fiber is an optical fiber made of pure silica and is commonly used for long-distance, high-speed, and broadband communication transmission. It has a lower transmission loss and a longer transmission distance, but a higher cost.

Fluorine-doped fiber: Fluorine-doped fiber is a new type of optical fiber made of fluorine in quartz fiber. It has a low refractive index and low signal attenuation, making it suitable for long-distance, high-speed, and wideband communication transmission.

Infrared fiber: Infrared fiber is a type of optical fiber used to transmit infrared light, which is commonly used for high-precision measurement and control in the military, aerospace, and industrial fields.

Composite fiber: A composite fiber is an optical fiber composed of two or more materials, which is usually used for the transmission of optical signals at a specific wavelength or to achieve special transmission effects.

In addition, there are special types of optical fibers such as dispersion displacement optical fibers, dispersion flat optical fibers, dispersion compensation optical fibers, polarization holding optical fibers, birefringence optical fibers, malignant environment resistant optical fibers, sealed coated optical fibers, carbon coated optical fibers, metal-coated optical fibers, and rare earth doped optical fibers.

The above are some common types of fibers, each with its own specific application scenarios and benefits.

Multimode Fiber In multimode fiber, optical signals propagate through multiple paths; It is generally recommended to apply when the distance is less than a mile.

The effective distance of multimode fiber from transmitter to receiver is about 5 miles. The usable tracking is also affected by the type and quality of the transmitting and receiving device; The stronger the light source, the more sensitive the receiver and the farther the distance. Studies have shown that the bandwidth of multimode fiber is about 4000MB s.

Single-mode fibers are manufactured to eliminate pulse broadening. Due to the small core size (7-9 microns), light jumps are eliminated. Focused laser sources are used at 1310 and 1550 nm wavelengths.

These lasers are directed into the tiny core and propagated to the receiver without significant jumps. If multimode can be compared to hunting, which can load many projectiles into a human barrel at the same time, then a single mode is a rifle, and a single ray is like a bullet.

Single-mode fibers Single-mode fibers have a thinner core, allowing light to be emitted directly to the center. It is recommended for long distances.

In addition, the distance loss of a single-mode signal is smaller than that of a multi-mode signal. At the first 3,000 feet, a multimode fiber can lose up to 50% of its LED signal intensity, while a single-mode fiber can only lose its laser signal at the same distance.

The bandwidth potential of single-mode makes it the only option for high-speed and long-distance data transmission. Recent tests have shown that 40G Ethernet 64 channels can be transmitted over a distance of up to 2,840 miles on a single single-mode optical cable.

In safety applications, the most common determining factor in choosing between multimode and singlemode is distance. If you only have a mile, multimode is preferred, because LED transmitters and receivers are much cheaper than the lasers required for singlemode. If the distance is greater than 5 miles, single-mode fiber is optimal.

Another issue to consider is bandwidth; If future applications may include the transmission of high-bandwidth data signals, then singlemode will be the best choice.

Answer]: a, b, c

Optical fibers can be classified in the following ways:

1) According to the different materials used to make the stool, it can be divided into quartz optical fiber, plastic optical fiber, glass optical fiber, etc.

2) According to different transmission modes, it can be divided into multi-mode fiber and single-mode fiber.

3) According to the distribution of the refractive index of the core, it can be divided into Tuchang bond travel type fiber and gradient type fiber.

4) According to the different working wavelengths, it can be divided into short-wavelength optical fibers, long-wavelength bright and bright fibers and ultra-long-wavelength optical fibers.

Optical fiber access networks can be technically divided into two categories: active optical networks and source mountain passive optical networks

1. Active optical network is a point-to-multipoint optical communication system, which is composed of ONU, optical remote terminal OLT and optical fiber transmission line.

2. The passive hail network is a pure medium network, which avoids the electromagnetic interference and lightning influence of external equipment, reduces the failure rate of lines and external equipment, improves the reliability of the system, and saves maintenance costs, which is the technology that the telecommunications maintenance department has been looking forward to for a long time.