Question 10 on Active Optical Networks

Passive optical network (PON) 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 system reliability, and saves maintenance costs.

Passive optical network (PON) refers to the optical distribution network (ODN) between the OLT and ONU, without any active electronic devices, it includes ATM-based passive optical network APON and IP-based PON.

It is the key device in the optical communication system to convert electrical signals into optical signals or convert optical signals into electrical signals, and is the heart of the optical transmission system.

After the optical signal is transmitted through the optical fiber to the receiving end, there is an element at the receiving end that receives the optical signal. However, since our understanding of light has not yet reached the level of understanding electricity, we cannot obtain the original signal through the direct restoration of the light signal. There is also a process of converting optical signals into electrical signals, which are then amplified by electronic circuits, and finally returned to the original signal.

Optical fiber amplifier is an indispensable key device in the new generation of optical fiber communication system, which can not only directly amplify the optical signal, but also have real-time, high-gain, broadband, low-noise, low-loss all-optical amplification functions. Because this technology not only solves the limitation of attenuation on the transmission rate and distance of optical networks, but also creates the wavelength division multiplexing of the 1550nm frequency band.

development

The research on optical active devices in China began in the 70s of the 20th century. The Institute of Semiconductors of the Chinese Academy of Sciences, the Wuhan Academy of Posts and Posts, the 44th Institute of the Ministry of Electronics, the 13th Institute of the Ministry of Electronics and other units have carried forward the spirit of "self-reliance" and developed the so-called short-wavelength optical devices with a wavelength of 850nm, such as LD and LED light sources with homojunction or heterojunction structures of Gaalas Gaas materials, Si-PIN detectors, etc.

Since then, these units have developed so-called long-wavelength devices with wavelengths of 1310 nm and 1550 nm, such as semiconductor lasers with a hail hole buried biprime structure using Ingasp In materials, and PIN detectors using Ingasp In materials.

The above inner circle is clear and capacitant refer to Encyclopedia-Optical Active Devices.

Active optical networks: Active components, such as optical amplifiers, are used in the optical transmission process.

Passive optical networks: Active components, such as optical splitters, are not used in the optical transmission process.

Hello landlord. To know about passive optical networks, we must first understand passive and optical networks, simply put, passive is relatively active, the "source" here refers to the power supply, you must know that the normal operation of communication equipment is inseparable from the power of the world, so most of the active equipment, followed by the optical network, is relative to the traditional copper cable transmission, copper cable cost is low, the transmission distance is near, the signal attenuation is large, then the passive optical network refers to the base station that can work normally without power to perform a system of optical signal transmission, It is a device that must set up a base station in some remote mountains and forests to amplify optical signals and then pull it to the remote end, or to carry out single-mode and double-mode switching or single-double fiber conversion, and can complete the task without the support of power supply.

In general, a passive optical network is a communication system that can complete the transmission of optical signals without the need for power supply.

Passive optical networks have a good application prospect and can withstand some harsh environments.

Passive optical network (PON) refers to the optical distribution network (ODN) between OLT and ONU, without any active electronic devices, including ATM-based passive optical network APON and IP-based passive optical network E GPON.

The light-free network is a point-to-multipoint optical fiber transmission and access technology, which adopts the broadcast mode for the downlink and the time-division multiple access mode for the uplink, which can flexibly form a tree, star, bus and other topologies, and only needs to darken a simple optical brancher at the optical branch point, so it has the advantages of saving optical cable resources, sharing bandwidth resources, saving investment in the computer room, fast network construction speed, and low comprehensive network construction cost.

There are two types of networks: ATM-PON and Ethernet-PON.

Passive optical network (PON) 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 system reliability, and saves maintenance costs.

Passive optical network (PON) is a pure dielectric network, which avoids the electromagnetic interference and lightning influence of external equipment, reduces the failure rate of lines and external equipment, improves system reliability, and saves maintenance costs.

The light-free network is a point-to-multipoint optical fiber transmission and access technology, the downlink adopts the broadcast mode, the uplink adopts the time-division multiple access mode, which can flexibly form a tree-shaped, star-shaped, bus-type and other topological source structures, and only a simple optical brancher needs to be installed at the optical branch point, so it has the advantages of saving optical cable resources, bandwidth resource sharing, saving equipment room investment, fast network construction speed, and low comprehensive network construction cost. There are two types of passive optical networks: ATM-PON and Ethernet-PON.

Development trend: China's previous mainstream wired access technology infiltration circular surgery includes ADSL, LAN, HFC, PLC and FTTH, some of which use PON+LAN, and wireless access technology has WLAN, Wimax, WiFi, Bluetooth, 3G and other technologies.

In the past, there were two main research goals of broadband access networks, the first is to develop in the direction of high-speed, safe and intelligent dimensions, requiring more flexible, user-oriented and lower costs, and FTTH is an outstanding representative in the field of wired access. The other is the integration of multiple services, that is, the access of IPTV, cable TV**, traditional voice and data services can be flexibly provided on the same platform.

Passive optical networks consist of ().

Correct answer: ABC

a.OLT (Optical Line Terminal) on the local side

b.The ONU (Optical Network Unit) on the user's side

optical distribution network is scarce).

Passive optical splitter coupling ruler).

Definition of a light source

In physics, it refers to electromagnetic waves that can emit a certain range of scattered wavelengths, including visible light and invisible light such as ultraviolet, infrared, and X-rays.

And we usually refer to luminaries that emit visible light as light sources. The sun, stars, lamps, and burning matter are all sources of light. However, such as the surface of the moon, the desktop, the white paper, the paper book, etc., cannot be called a light source, because they rely on the reflection of foreign light to make people see them, and such reflective objects cannot be called light sources or luminous objects.