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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

:: What Is an Photodetector? An optical detector is a device that converts light signals into electrical signals, which can then be amplified and processed. The photodetector is as essential an element of any fiber optic system as the optical fiber or the light source. Photodetectors can dictate the performance of a fiber optic communication link. :: Semiconductor Photodiodes Semiconductor photodiodes are the most commonly used detectors in optical fiber systems since they provide good performance, being small in size, and are of low cost. Semiconductor photodiodes are made of silicon, germanium, GaAs, InGaAs, etc. :: How Does a Photodetector

:: What Is OM4 Fiber Anyway? OM4 fiber is a laser-optimized, high bandwidth 50um multimode fiber. OM4 fiber is not a new fiber type. All major fiber manufacturers have been selling a fiber with an effective modal bandwidth (EMB) value equivalent to that specified by OM4 since 2005. The change is that there is now a standard that is specifically targeted at this product. Prior to the standardization of OM4, these higher bandwidth fibers were sold as a part of OM3. OM3 and OM4 fiber are referred to as “laser-optimized” multimode fibers because they are specifically designed for optimum performance

:: Laser Diode to Fiber Coupling Techniques The brute-force approach of simply butting an optical fiber almost against the laser diode allows for only about 10-20% coupling efficiency, or a 7 to 10dB coupling loss. The coupling approach is show below. This is partially because that the laser diode emission pattern is somewhat elliptical. Analytical expressions for such patterns have been used for both LED and LD (laser diode). So other coupling techniques were developed using various lenses to reduce the coupling loss. This is shown in the following illustration. Some of these techniques use lenses that are cylindrical instead