Archived — Fiber Optic Technology

================================================================================================ Frequency dispersion in groups of gravity waves on the surface of deep water. The red dot moves with the phase velocity, and the green dots propagate with the group velocity. In this deep-water case, the phase velocity is twice the group velocity. The red dot overtakes two green dots when moving from the left to the right of the figure. ================================================================================================ The velocity of a wave can be defined in many different ways, partly because there many different kinds of waves, and partly because we can focus on different aspects or components of any given wave. The ambiguity in

>> What is exactly PCM? Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems. A PCM stream is a digital representation of an analog signal, in which the magnitude of the analogue signal is sampled regularly at uniform intervals, with each sample being quantized to the nearest value within a range of digital steps. For digital communication, there are two quite different PCM standards. The North American standard,

>> Nonlinear Effects in High Power, High Bit Rate Fiber Optic Communication Systems When optical communication systems are operated at moderate power (a few milliwatts) and at bit rates up to about 2.5 Gb/s, they can be assumed as linear systems. However, at higher bit rates such as 10 Gb/s and above and/or at higher transmitted powers, it is important to consider the effect of nonlinearities. In case of WDM systems, nonlinear effects can become important even at moderate powers and bit rates. There are two categories of nonlinear effects. The first category happens because of the interaction of light

1. What Is a Wavelength Selective Switch (WSS)? WSS stands for Wavelength Selective Switch. WSS has become the central heart of modern DWDM reconfigurable Agile Optical Network (AOC). WSS can dynamically route, block and attenuate all DWDM wavelengths within a network node. The following figure shows WSS’s functionality. The above figure shows that a WSS consists of a single common optical port and N opposing multi-wavelength ports where each DWDM wavelength input from the common port can be switched (routed) to any one of the N multi-wavelength ports, independent of how all other wavelength channels are routed. This wavelength switching

:: Ethernet Is Not a LAN-only Technology Anymore With the introduction of 10 Gigabit Ethernet, Ethernet is not a LAN-only technology anymore. For most LAN backbones, 10 Gigabit Ethernet provides far more bandwidth than current demand. Wide Area Network (WAN) compatible 10 Gigabit Ethernet (10 GE) has become a very powerful and exciting solution when you consider its benefits from application in MANs, PoPs, and WANs. :: 10 Gigabit Ethernet in the Enterprise Ethernet is the actual LAN standard. During 1999, Gigabit Ethernet outshipped all other technologies, including ATM, for the first time. The economics of 10 GE and growing