Types of Optoelectronic Devices: Although light-emitting diodes and photodiodes are not quantum-mechanical devices in the Types of Optoelectronic Devices, they are semiconductor devices closely associated with lasers. It is most convenient to cover them here. Light Emitting Diodes (LEDs): The construction of an LED is similar to that of a laser diode, as indeed is …
Semiconductor Lasers: Semiconductor Lasers was discovered in 1962 that a gallium arsenide diode, such as the one shown in Figure 12-41, is capable of producing laser action. This occurs when the diode is forward-biased, so that effective dc pumping is needed (a very convenient state, of affairs). Depending on its precise chemical composition, the GaAs …
Continuous Wave Gas Laser: The first Continuous Wave Gas Laser, in 1961, was a gas laser using a mixture of helium and neon gases. These are still used, and a simplified He-Ne laser is shown in Figure 12-40. It operates in a manner similar to that of the ruby laser, with the following differences. 1.The …
Pulsed Ruby Laser: The Pulsed Ruby Laser is similar to the ruby cavity maser, to some extent, in that stimulation is applied to raise the chromium atoms to a higher energy level to secure a population inversion once again. However, this time pumping is With light, rather than with microwave, energy. Also, no magnetic field …
Cryogenically Cooled Amplifiers: The term solid-state is used deliberately here; it does not mean “semiconductor.” In terms of the somewhat older maser parlance, it means the opposite of gaseous, i.e., ruby. The cross section of a Cryogenically Cooled Amplifiers is shown in Figure 12-38. It is seen to be a single-port amplifier, so that a …
Ruby Maser: As was know ferrites of certain materials have atomic systems that can be made to resonate magnetically at frequencies dependent on the atomic structure of the material and the strength of the applied magnetic field. When such a resonance is stimulated by the application of a signal at that frequency, absorption will take …
Schottky Barrier Diode: Schottky junctions have been shown and described throughout this chapter, in conjunction with various devices that use them in their construction in Figure 12-4. Accordingly it will be realized that the Schottky Barrier Diode is an extension of the oldest semiconductor device of them all the point-contact diode. Here the metal-semiconductor interface …
Pin Diode Construction: The Pin Diode Construction consists of a narrow layer of p-type semiconductor separated from an equally narrow layer of n-type material by a somewhat thicker region of intrinsic material. The intrinsic layer is a lightly doped n-type semiconductor. The name of the diode is derived from the construction (p-intrinsic-n). Although gallium arsenide …
Impatt Diode Working: IMPATT Diode Working is a combination of delay involved in generating avalanche current multiplication, together with delay due to transit time through a drift space, provides the necessary 180° phase difference between applied voltage and the resulting current in an Impatt Diode Working. The cross section of the active region of this …
Gunn Diode Working Principle: A practical Gunn Diode Working Principle consists of a slice like the one shown in Figure 12-24, sometimes with a buffer layer between the active layer and the substrate, mounted in any of a number of packages, depending on the manufacturer, the frequency and the power level. Encapsulation identical to that …