Translate into Chinese. 1.Dense WDM however is ano...
Translate into Chinese. 1.Dense WDM however is another thing. Dense WDM refers to the close spacing of channels. Sadly, "dense" is a qualitative measure and just what dense means is largely in the mind of a particular individual. To some, a series of WDM channels spaced at 3.6 nm apart qualifies for the description. Others use the term to distinguish systems where the wavelength spacing is1nm per channel or less. 2.In 1998 the "happening” Wavelength Division area in optical communications was Multiplexing (WDM). This is the ability to send many (perhaps up to 1000) independent optical channels on a single fiber. 3.If a short pulse of light from a source such as a laser or an LED is sent down a narrow fiber, it will be changed (degraded) by its passage down the fiber. It will emerge (depending on the distance) much weaker, lengthened in time ("smeared our"), and distorted in other ways. 4.In the wide area environment a large coaxial cable system can easily involve a cable of several inches in diameter and weighing many pounds per foot. 5.It is possible to tap fiber optical cable. But it is very difficult to do and the additional loss caused by the tap is relatively easy to detect. There is an interruption to service while the tap is inserted and this can alert operational staff to the situation. In addition, there are fewer access points where an intruder can gain the kind of access to a fiber cable necessary to insert a tap.