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this Raman amplifier is used for long distance in dwdm technology. Basically this amplier has high gain...
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∙ 11y ago
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What is the difference between sdh and dwdm?
nothing
Explain how a single fiber optic cable can handle two way communication both half and full duplex?
A single fiber optic cable can facilitate two-way communication through a method called wavelength division multiplexing (WDM). WDM enables the transmission of multiple signals (or wavelengths of light) simultaneously over the same fiber optic cable, allowing for both half-duplex and full-duplex communication. Here's a brief explanation of how this works: Wavelength Division Multiplexing (WDM): Wavelength division multiplexing involves using different wavelengths of light to carry multiple signals over the same fiber optic cable. Two common types of WDM are: Coarse Wavelength Division Multiplexing (CWDM): Uses fewer wavelengths spread over a wider range. Dense Wavelength Division Multiplexing (DWDM): Utilizes more closely spaced wavelengths, allowing for higher data capacity. Half-Duplex Communication: In half-duplex communication, data can be transmitted in both directions, but not simultaneously. WDM can be configured to use different wavelengths for upstream and downstream communication. For example, one wavelength can be assigned for transmitting data from the source to the destination (upstream), and another wavelength for transmitting data from the destination back to the source (downstream). Full-Duplex Communication: In full-duplex communication, data can be transmitted simultaneously in both directions. This can be achieved by using separate wavelengths for upstream and downstream, allowing for independent transmission paths. For instance, one wavelength can be dedicated to upstream data flow, while another wavelength is used for downstream data flow. Bidirectional Communication: By utilizing different wavelengths for different directions, the fiber optic cable effectively supports bidirectional communication. Each communicating party can use its assigned wavelength to transmit and receive data independently. In summary, Wavelength Division Multiplexing (WDM) allows a single fiber optic cable to handle two-way communication, whether it's half-duplex or full-duplex, by employing different wavelengths for different communication paths. This enables simultaneous data transmission in both directions over the same fiber optic link.
What Are the Common Optical Devices in DWDM System?
Dense wavelength-division multiplexing (DWDM) is an optical fiber multiplexing technology that is used to increase the bandwidth of existing fiber networks. It combines data signals from different sources over a single pair of optical fiber, while maintaining complete separation of the data streams. This is a laser technology used to increase bandwidth over existing fiber optic backbones. DWDM technology is an extension of optical network, the main advantage of DWDM is that it is independent of protocol and transmission rate, DWDM-based network can transmit data in IP, ATM, SONET, SDH and Ethernet. Optical devices in DWDM system: DWDM optical transceiver modules, DWDM MUX/DEMUX, DWDM OADM and optical amplifiers. DWDM Transceiver Modules DWDM optical module is an important device for photoelectric signal conversion. Every DWDM transceiver module has its own specific wavelength, using DWDM technology can greatly save fiber resources. Most DWDM transceiver modules (DWDM SFP，DWDM SFP+，DWDM XFP, etc) on the market today are operating at 100GHz and 50GHz. DWDM Mux/Demux DWDM Mux combines data signals from different sources over a single pair of optical fiber, while maintaining complete separation of the data streams. Conversely, DWDM Demux refers to the type of combinational circuit that accepts just a single input but directs it through multiple outputs. Instead of using a single fiber in each pair of optical transceiver modules, DWDM allows multiple optical channels to share the same fiber optic cable. AAWG Athermal AWG (Arrayed Waveguide Grating), or AAWG, is based on silica-on-silicon planar technology. It mainly realizes the functions of multiplexing and demultiplexing for more than 16 channels. AAWG has thermal stability and improved ITU-Grid accuracy that ITU-G694.1 requires for with wider transmission bandwidth, thus it can be applied to high-end areas such as Metro/long-haul DWDM optical communication system. DWDM OADM An optical add-drop multiplexer (OADM) is a device used in wavelength-division multiplexing systems for multiplexing and routing different channels of light into or out of a single mode fiber. The OADM based on DWDM technology is moving the telecommunications industry significantly closer to the development of optical networks. The OADM can be placed between two end terminals along any route and be substituted for an optical amplifier. Commercially available OADMs allow carriers to drop and/or add up to multi channels between DWDM terminals. By deploying an OADM instead of an optical amplifier, service providers can gain flexibility to distribute revenue–generating traffic and reduce costs associated with deploying end terminals at low traffic areas along a route. Erbium-doped optical Fiber Amplifier Erbium-doped optical Fiber Amplifier (EDFA) is now most commonly used to compensate the loss of an optical fiber in long-distance optical communication. Another important characteristic is that EDFA can amplify multiple optical signals simultaneously, and thus can be easily combined with WDM technology. Optical amplifiers can amplify optical signals in a wide wavelength range, which is very important for DWDM system applications. In contrast to the EDFA used in CATV or SDH systems, the EDFA in DWDM system is also referred to as DWDM EDFA.To extend the transmission distance of the DWDM system, you can choose from different types of optical amplifiers,including DWDM EDFA, CATV EDFA, SDH EDFA, EYDFA and Raman amplifier, etc.
When was DWDM-FM created?
DWDM-FM was created in 1987.
What is dwdm?
DWDM is a radio station in Metro Manila. You can find it at 95.5 FM and it is an adult contemporary type of station.
What is the difference between sdh and dwdm?
nothing
Which of the following multiplexing technologies uses fiber optics?
DWDM
What does DWDM transport stand for?
Dense Wavelength Division Multiplexing
Why DWDM can not work for Satellite communications systems?
DWDM works well for fiber (point to point connectivity) but not for satellites where we have processing time (specially in satellites where satellites have onboard processing where the received signal of radio wave is broken down to intermediate frequencies down to base band, re-process, re-generate and send it back to intermediate frequency and then to an RF frequency for re- transmission back to earth) but there is no way that we can do all of this processing in the middle of our transmission. All of these processing takes time and unless you have Time division type of operation e.g. TDMA or CDMA.
How many DWDM optical channel of 50 MHz can be transmitted in a CWDM optical channel?
120 channels / 80 channels on C band and 40 on L band
What is the technique used to transmit and receive multiple signals using multiple frequencies over one cable?
DWDM (Dense Wavelength Division Multiplexing)
What is the difference between WDM and DWDM?
WDM classification is based on channel spacing between two wavelengths * channel spacing greater than 200GHZ is called as CWDM * channel spacing greater than 100GHZ is called as WDM * channel spacing lesser than 100GHZ is called as DWDM * channel spacing lesser than 25GHZ is called as UDWDM 100GHZ = 0.8nm WDM classification is based on channel spacing between two wavelengths * channel spacing greater than 200GHZ is called as CWDM * channel spacing greater than 100GHZ is called as WDM * channel spacing lesser than 100GHZ is called as DWDM * channel spacing lesser than 25GHZ is called as UDWDM 100GHZ = 0.8nm
What's the difference of CWDM, DWDM and CCWDM?
How does WDM work? A WDM system uses a multiplexer at the transmitter to join the several signals together and a demultiplexer at the receiver to split them apart. There are multiplexer(MUX) and demultiplexer(DEMUX). The main function of MUX is to combine multiple signal wavelengths in one fiber for transmission at the sending end. And the main function of the demultiplexer DEMUX is to separate multiple wavelength signals transmitted in an optical fiber at the receiving end. The main purpose of wavelength division multiplexing(WDM) is to increase the available bandwidth of the fiber. Therefore, wavelength division multiplexing systems are widely used by telecom companies to expand capacity through WDM without laying more fibers. CWDM, DWDM, CCWDM, How to choose? CWDM is sparse wavelength division multiplexer, also known as coarse wavelength division multiplexer. CWDM is being used in cable television networks, where different wavelengths are used for the downstream and upstream signals. In these systems, the wavelengths used are often widely separated. DWDM is dense wavelength division multiplexer. Dense wavelength division multiplexing (DWDM) refers originally to optical signals multiplexed within the 1550 nm band so as to leverage the capabilities (and cost) of erbium doped fiber amplifiers (EDFAs), which are effective for wavelengths between approximately 1525–1565nm (C band), or 1570–1610nm (L band). CCWDM is a mini wavelength division multiplexer, which is a mini version of CWDM. A wavelength division multiplexing technology based on TFF (Thin Film Filter), which works in the same way as CWDM. The difference is that CCWDM uses free space technology, its package size is smaller and the insertion loss is lower. It can replace CWDM products in telecom, enterprise networks, PON networks, TV and other applications. The main advantage of the CWDM system is the low cost. The device cost is mainly manifested in filters and lasers. The wide wavelength spacing of 20nm also makes CWDM the advantage of low specification of the laser and simplified structure of the optical multiplexer/demultiplexer. The simplified structure and high yield will reduce the cost. The increased cost of DWDM is mainly due to the high cost of laser diodes and the cooling laser technology used to maintain wavelength stability. CWDM, DWDM and CCWDM are kinds of effective methods to solve the increasing bandwidth capacity needs; but they are designed to meet different network needs.
What is an optical amplifier EDFA for a WDM system?
What's EDFA? Erbium-Doped Fiber Amplifier (EDFA) is an optical amplifier used in the C-band and L-band, where the loss of telecom optical fibers becomes lowest in the entire optical telecommunication wavelength bands. It is used in the telecommunications field and in various types of research fields. An EDFA is "doped" with a material called erbium. Optical amplifiers can directly amplify optical signals without converting the signals into electrical signals before amplification, which is also the most prominent function and is an important optical component in long-distance optical communication. EDFA has been widely used in DWDM system, usually used to compensate the link loss in long-distance optical communication. The most important feature is to amplify multiple optical signals at the same time and can be easily combined with Wavelength division multiplexing (WDM) technology. The common bands of EDFA are C-band and L-band. Wavelength division multiplexing (WDM) techniques combined with erbium-doped fiber amplifier (EDFA) increases the capacity of light wave transmission, provides high capacity and improves flexibility of optical network technology. EDFA Working Principle EDFA works on the principle of stimulating the emission of photons. With EDFA, an erbium-doped optical fiber at the core is pumped with light from laser diodes. The erbium-doped fiber (EDF) is at the core of EDFA technology, which is a conventional silica fiber doped with Erbium. It is a conventional silica fiber doped with erbium. When the Erbium is illuminated with light energy at a suitable wavelength (either 980nm or1480nm), it is excited to a long lifetime intermediate state, then it decays back to the ground state by emitting light within the 1525-1565nm band. When the light energy already exists within the 1525-2565nm band, for example due to a signal channel passing through the EDF, then this stimulates the decay process, resulting in additional light energy. Baisc configuration of EDFA EDFA configuration is mainly composed of erbium-doped fiber (EDF), pump laser, coupler, WDM, optical isolator, gain flattening filter (GFF), variable optical attenuators (VOA) and photodetector (PD). In principle, EDFAs can be designed such that pump energy propagates in the same direction as the signal (forward pumping), the opposite direction to the signal (backward pumping), or both direction together. Coupler: the optical power is branched and transmitted according to a certain proportion, usually using the melting taper process. WDM: a passive optical device that mixes up the input optical signal and the light wave output from the pump light source, generally using a wavelength division multiplexer(WDM). Optical Isolator: a device that prevents reflected light from affecting the stability of optical amplifier and ensures that the optical signal can only be transmitted in the forward direction. EDF: EDF is the main body of the optical amplifier. It can be used to design erbium-doped optical amplifiers (EDFA) for telecommunication in the C and L band and sensing applications. Pump Laser: a semiconductor laser with center wavelength 980nm that provides energy for signal amplification, the output optical power ranges from 10mW to 1W. GFF: suppress ASE noise to reduce the impact of noise on EDFA performance and improve EDFA gain flatness and OSNR. VOA: a device that dynamically adjusts optical power, often used in adjusting the gain slope and power attenuation. PD: monitor the input and output optical power in real time. Types of EDFA Optical Amplifiers Booster Amplifier An amplifier operates at the transmission side of the link, designed to amplify the signal channels exiting the transmitter to restore the strength of a transmitted signal. When used as the booster amplifier, EDFA is deployed in the output of an optical transmitter to improve the output power of the multi-wavelength signal having been multiplexed. Pre-amplifier A pre-amplifier EDFA operates at the receiving end of a DWDM link. The pre-amplifier is used to compensate for losses in a demultiplexer near the optical receiver. It operates at the receiving end of a DWDM link and works to enhance the signal level before the photo detection takes place in an ultra-long haul system.Being equipped with these features, EDFA can significantly improve the sensitivity of an optical receiver when deployed in the input of an optical receiver.
