Topic: Introduction to Dense Wave Division Multiplexing (DWDM).
This paper covers the how the need for Wave Division Multiplexing (WDM) and Dense WDM became essential and the basic difference between WDM and DWDM. Alternatives to DWDM are explored including Time Division Multiplexing (TDM) and Optical TDM (OTDM). An example of the difference between TDM and WDM is shown in a detailed example. The major components of a WDM system are explored. A few vendor products providing DWDM, the major features of each product, and the product capacities are compared. This paper concludes with some potential deficiencies of a DWDM system.
Introduction.
The Need For Fiber.
The first generation optical networks, circa 1960, used single wavelength transmission and electrical-based switches for routing and processing. By using electrical switches, the optical signal must be converted to an equivalent electrical signal, processed by the electrical-based switches, and converted back to an optical signal. This significantly slowed down the otherwise optical network, as the transmission along a particular logical path is as fast as the slowest link. .
If you think of a road between two points, imagine the road surface is made of different materials. At some points, the road is made of a material like concrete that allows high-speed travel similar to a highway, where the maximum safe speed is relatively high. Along other sections, the road is made of concrete marred with potholes or compacted dirt that allows for fast travel, but because of the road material, the maximum safe speed of the road is slower than a highway. Although the traveled speed along the highway is quick, the speed traveled along the dirt road is slower, thus slowing down the overall transmission by increasing delay. Similarly, early optical networks were "slowed down" by using electrical switches in the transmission path. This was not an issue in early optical networks because the amount of traffic along the fiber optic paths was small during the 1960's.
In addition, recent estimates of capacity suggest that potential capacity (brought online through fibre upgrades and the application of Dense Wave Digital Multiplexing (DWDM) technology) in existing infrastructure is many times that of the installed capacity. All major providers of `backbone' capacity are currently implementing DWDM. ...
FUTURE OPTICAL COMPUTER STORAGE-Holographic Memory Section 1- Introduction Every year, we cannot fail to notice how computer systems increase greatly in speed, memory capacity and performance. ... This idea is known as Angle Multiplexing. ... The idea of angle multiplexing can be extended by having a disc covered in thousands of small crystals. Each crystal contains many angle-multiplexed holograms, and so the capacity of the disc is thousands of times bigger then a single crystal. This idea is known as Spatial Multiplexing. ...
Two basic digital ingredients are included in a DAB system: - MUSICAM (Masking Pattern Adapted Universal Sub-band Integrated Coding and Multiplexing), which is a data reduction technique, - COFDM (Coded Orthogonal Frequency Division Multiplexing), which is a broadband multiplexing technique, serving to enhance reception resilience in a multipath environment. ... The current development of the DAB system shows that the following advantages in comparison with VHF/FM can also be obtained: • The spectrum efficiency of DAB means that it is possible to increase the number of radio statio...
Peter John Graham's book, The French New Wave: Critical Landmarks, debates the social and political implications of the New Wave Movement. ... The political division between Left Wingers and Right Wingers drew a line between filmic groups. ... According to Graham the French youth were drawn to New Wave films because of the rebellious nature that connected them: "Many New Wave films spoke to young audiences about their lives. ... The divisions between Left and Right parties paralleled the complexities the artistic world faced: whether the film industry would be socially progressive or...
The drastic drop was caused by the introduction of television sets and VCRs. ... The multiplex was adapted from the American company American Multi Cinema Entertainment and the first multiplex was opened in Kansas, USA. ... Multiplexes are showing different films from all types of genres-from comedy to science fiction. ... Some multiplexes also offer a sit down meal for a higher price, to the consumer. ... The increase of film admissions at the time the multiplex was introduced shows this. ...
Introduction to SONET Synchronous optical network (SONET) is a standard for optical telecommunications transport that was created in 1984. ... Asynchronous multiplexing uses multiple stages. ... STS multiplexer to add/drop multiplexer, two add/drop multiplexers, two STS multiplexers) and these devices are called line-terminating equipment. ... STS multiplexers and add/drop multiplexers provide these functions. ... STS multiplexers provide these functions. ...
Some of the technologies involved in the cellular field are Time Division Multiplexing Access Coded Division Multiplexing Access Global System for Mobile Communications Cellular telephones have evolved from being large cumbersome devices used only to place calls, into small gadgets loaded with features, games, MP3 players, radios, and Internet enabled service, just to name a few. ...
Cell Division The two main phases of cell division are interphase and the mitotic phase. ... Mitosis, the division of the nucleus, is broken into five sub-phases: prophase, prometaphase, metaphase, anaphase, and telophase. ... During telophase the nuclear envelope reforms around the chromosomes and the chromatin fiber of the chromosomes becomes less dense. ...
The group that was most affected by the events of the July, 1995 heat wave was the increasing population of poor elderly who live alone in social isolation, especially those who live in areas with exceedingly high crime rates. ... Of those that were least affected by the heat wave, Chicago's Latino population stands out above all others. ... Without the development of these networks, many of the people who suffered through the heat wave never received help on time, and fell victim to the very thing that was supposed to keep them safe, their home. ... Little Village is one of the most ...
