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>> What is Intensity Modulation with Direct Detection (IM/DD)? Current fiber optic lightwave communication systems are based on a simple digital transmission scheme in which an electrical bit stream is used to modulate the intensity of the optical carrier, and the optical signal is detected directly at a photodiode to convert it to the original digital signal in the electrical domain. Such a scheme is referred to as intensity modulation with direct detection (IM/DD). >> What is Coherent Optical Communication? In contrast to intensity modulation with direct detection (IM/DD), many alternative schemes, well known in the context of radio and

1. What is fiber optic transponder? In optical fiber communications, a transponder is the element that sends and receives the optical signal from a fiber. A transponder is typically characterized by its data rate and the maximum distance the signal can travel. >> The difference between a fiber optic transponder and transceiver A transponder and transceiver are both functionally similar devices that convert a full-duplex electrical signal in a full-duplex optical signal. The difference between the two being that transceivers interface electrically with the host system using a serial interface, whereas transponders use a parallel interface to do so. So

>> Fiber Optic Connectors Are Fragile All fiber optic connectors should be taken care of as a high quality lens of a good camera. Even a small fingerprint can lead to big trouble. The weak link in many fiber optic communication systems, and in optical instrument reliability, is the use and care of the fiber optic connector. After so many years of improvement, current fiber connectors are so easy to use, that people tend to be vigilance in connector care and cleaning. However, remember this, it only takes ONE time of a missed cleaning for a piece of grit to

>> A Brief Introduction of Rare-Earth Doped Fibers Rare-earth doped fiber is an optical fiber in which ions of a rare-earth element, such as neodymium, Erbium or holmium, have been incorporated into the glass core matrix, yielding high absorption with low loss in the visible and near-infrared spectral regions. Fiber lasers and fiber amplifiers are nearly always based on glass fibers which are doped with laser-active rare earth ions (normally only in the fiber core). These ions absorb pump light, typically at a shorter wavelength than the laser or amplifier wavelength (except in upconversion lasers), which excites them into some

>> What is Power over Ethernet? 1. Introduction Power-over-Ethernet (PoE) or "Active Ethernet" eliminates the need to run 110/220 VAC power to Wireless Access Points and other devices on a wired LAN. Using Power-over-Ethernet system, installers need to run only a single CAT5 Ethernet cable that carries both power and data to each device. This allows greater flexibility in the locating of AP’s and network devices and significantly decreasing installation costs in many cases. Power over Ethernet (PoE) technology describes a system to pass electrical power safely, along with data, on Ethernet cabling. The IEEE standard for PoE requires category