http://koolkampus.com/engineering-notes-3 Electronics, Electrical, Instrumentation and Communication : KoolKampus.com Sat, 18 Nov 2006 05:38:54 +0000 http://backend.userland.com/rss092 en Optical Splices Splices are permanent connections between two fibers made by arc-welding the fibers together (fusion splicing) or gluing them together (mechanical splicing.)  Both splices are capable of splice losses in the range of 0.15 dB (3%) to 0.1 dB (2%). In a mechanical splice, the ends of two pieces of fiber ... http://koolkampus.com/engineering-notes-3/communication/optical-splices/ Optical Connector Connectors are used to mate a fiber to another fiber or to equipment.  Good coupling efficiency requires precise positioning of the fiber.  Connectors are used when one expects that the connection must occasionally be  broken. Optical connectors are similar to their electrical counterparts in function and outward appearance.  They must, ... http://koolkampus.com/engineering-notes-3/communication/optical-connector/ LASER Diode Laser Diodes are complex semiconductors that convert an electrical current into light. The conversion process is fairly efficient in that it generates little heat compared to incandescent lights. Laser action (with the resultant monochromatic and coherent light output) can be achieved in a p-n junction formed by two doped gallium ... http://koolkampus.com/engineering-notes-3/communication/laser-diode/ LED (Light Emmiting Doide) LEDs are p-n junction devices constructed of gallium arsenide (GaAs), gallium arsenide phosphide (GaAsP), or gallium phosphide (GaP). Silicon and germanium are not suitable because those junctions produce heat and no appreciable IR or visible light. The junction in an LED is forward biased and when electrons ... http://koolkampus.com/engineering-notes-3/communication/led/ Michealson Interferometer An Michealson Interferometer constructed using a half-silvered mirror inclined at a 45° angle to the incoming beam. Half the light is reflected perpendicularly and bounces off a beamsplitter; half passes through and is reflected from a second beamsplitter. The light passing through the mirror must also pass through an inclined ... http://koolkampus.com/engineering-notes-3/communication/michealson-interferometer/ Mach-Zehnder Interferometer The Mach-Zehnder Interferometer has two input ports and two output ports. The light is split in the two arms of the input coupler of the interferometer, and they are later recombined in the output coupler of the interferometer. The optical length of the two arms is unequal, ... http://koolkampus.com/engineering-notes-3/communication/mach-zehnder-interferometer/ Optical communication Jun-Ichi Nishizawa, known as "Father of Japanese Microelectronics", born September 12,1926 in Sendai(Japan) is a Japanese engineer who is known for his invention of optical communication systems (including optical fiber, laser diode, etc), SIT/SITh (Static Induction Transistor/Thyristor) and PIN diode. The use of electromagnetic waves in the region ... http://koolkampus.com/engineering-notes-3/communication/introduction-to-optical-communication/ Phase Shifters Phase shifters are used to change the transmission phase angle (phase of S21) of a network. Ideally phase shifters provide low insertion loss, and approximately equal loss in all phase states. While the loss of a phase shifter is often overcome using an amplifier stage, the less loss, the ... http://koolkampus.com/engineering-notes-3/communication/phase-shifters/ Attenuators Attenuators are passive resistive elements that do the opposite of amplifiers, they kill gain. What is the need of suppressing the gain? The answer is, suppose your design specification calls for 10 dB gain, with a 1.2:1 maximum VSWR, you search the amplifier vendors, and locate an amplifier in your ... http://koolkampus.com/engineering-notes-3/communication/attenuators/ Microstrip Microstrip is a planar transmission line, similar to stripline and coplanar waveguide. Microstrip was developed by ITT laboratories as a competitor to stripline. Microstrip transmission lines consist of a conductive strip of width "W" and thickness "t" and a wider ground plane, separated by a dielectric layer (a.k.a. the "substrate") of ... http://koolkampus.com/engineering-notes-3/communication/microstrip/