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How many DWDM optical channel of 50 MHz can be transmitted in a CWDM optical channel?
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120 channels / 80 channels on C band and 40 on L band
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∙ 12y ago
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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 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.
Application of Raman amplifier in DWDM systems?
this Raman amplifier is used for long distance in dwdm technology. Basically this amplier has high gain...
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
What is C band and L band in WDM?
WDM (Wavelength Division Multiplexing ) is a transmission technology that uses one optical fiber to simultaneously transmit multiple optical carriers of different wavelengths. The transmission loss in optical fiber varies with the wavelength of light. In order to reduce loss as much as possible and ensure transmission effect, it is necessary to find the most suitable wavelength for transmission. After a long time of exploration and testing, light in the wavelength range of 1260nm~1625nm has the lowest signal distortion and loss caused by dispersion, and is most suitable for transmission in optical fiber.(glsun dot com) The wavelength applications of optical fibers are divided into several bands, and each band is used as an independent channel to transmit an optical signal of a predetermined wavelength. ITU-T divides the frequency band of single-mode optical fiber more than 1260nm into several bands: O, E, S, C, L and U. O Band O band is the original band with wavelength range 1260-1360 nm. O band is the first wavelength band historically used for optical communication, with minimal signal distortion (due to dispersion). E Band E band is the extended band with wavelength range 1360-1460 nm. It is the least common of these wavebands. E band is mainly used as an extension of O band, but its use in optical communications is limited mainly because many existing optical cables show high attenuation in E band and the manufacturing process is very energy intensive. S Band E band is the short wavelength band with wavelength range 1460-1530 nm. Fiber loss is lower in S band than in O band, and S band is used by many PON (passive optical network) systems. C Band C band is the conventional wavelength band with wavelength range 1530-1565 nm. Optical fiber has the lowest loss in C band and has a great advantage in long distance transmission system. EDFA technology is commonly used in many metropolitan, long-distance, ultra-long-distance and subsea optical transmission systems in combination with WDM. The use of C band has expanded with the advent of DWDM (Dense Wavelength Division Multiplexing), which enables multiple signals to share a single optical fiber. L Band C band is the long wavelength band with wavelength range 1565-1625 nm. It is the second lowest-loss wavelength band and is often used when C band is insufficient to meet bandwidth requirements. With the widespread availability of EDFA, DWDM systems have expanded up to L band and were initially used to expand the capacity of terrestrial DWDM optical networks. Now it has been brought in by undersea cable operators to do the same thing - expand the total capacity of undersea cables. U Band Because the transmission attenuation loss of C band and L band is the lowest, the signal light in DWDM system is usually selected to be at C band and L band. In addition to O band and L band, there are two other bands, namely the 850 nm band and the U band (ultra-long band: 1625-1675 nm). The 850 nm band is the main wavelength of multi-mode fiber communication system combined with VCSEL (Vertical cavity surface emitting Laser). U band is mainly used for network monitoring. Summary WDM technology can be divided into WDM, CWDM and DWDM according to different wavelength modes. The wavelength range stipulated by ITU for CWDM (ITU-T G.694.2) is 1271 to 1611 nm, but in application, considering the large attenuation of 1270-1470nm band, the band range of 1470~1610nm is usually used. DWDM channels are more densely spaced and use C-band (1530 nm-1565 nm) and L-band (1570nm-1610nm) transmission Windows. Ordinary WDM generally uses 1310 and 1550nm wavelengths. With the growth of FTTH applications, C band and L band, the most commonly used bands in fiber optic networks, will play an increasingly important role in optical transmission systems.
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.
What is the x2 transceivers?
A type of 10-gigabit Ethernet optical transceiver. 10GTEK's X2 is a standardized form factor for 10 Gb/s fiber optic transponders that is used for data transfer rates from 10.3 Gb/s to 10.5 Gb/s. It is protocol-specific: Either 10G Ethernet or 10G Fibre Channel versions are available. X2 transponders are used in datacom optical links only (not telecom), and they are smaller than old generation XENPAK transponders. Its electrical interface to the host board is also standardized and is called XAUI (4 x 3.125 Gb/s). 10GTEK manufactures X2 300m, X2 10km, X2 20km, X2 40km, X2 80km optical modules. All modules support Digital Optical Monitoring (DOM) function . 10GTEK offers the whole series of 10G X2, including: X2 10GBASE-SR 300M MMF OM3; X2 10GBASE-LRM MMF 220M; X2 10GBASE-LR SMF 10-20KM; X2 10GBASE-ER SMF 40KM; X2 10GBASE-ZR SMF 80KM; 40 Channels DWDM X2 ... ...
