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In semiconductor laser theory, the optical gain is produced in a semiconductor material. The choice of material depends on the desired wavelength and properties such as modulation speed. It may be a bulk semiconductor, but more often a quantum heterostructure. Pumping may be electrically or optically . All these structures can be described in a ...
The laser diode rate equations model the electrical and optical performance of a laser diode. This system of ordinary differential equations relates the number or density of photons and charge carriers in the device to the injection current and to device and material parameters such as carrier lifetime, photon lifetime, and the optical gain.
While in other laser materials like in gas lasers or solid state lasers, the processes associated with optical gain are rather simple, in semiconductors this is a complex many-body problem of interacting photons, electrons, and holes. Accordingly, understanding these processes is a major objective as being a basic requirement for device ...
[1] [2] For semiconductor lasers, the saturation effect is negligible. We derived the gain g for a Fabry-Perot semiconductor laser based on the density matrix equations and expressions for the natural linewidth. [1] [2] Thus, the linewidth theory [2] [8] [9] is an integral part of the nonlinear theory.
A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction.
Absorption is the active process in photodiodes, solar cells and other semiconductor photodetectors, while stimulated emission is the principle of operation in laser diodes. Besides light excitation, carriers in semiconductors can also be generated by an external electric field, for example in light-emitting diodes and transistors .
Gain-switching is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, of the order of picoseconds (10 −12 s). [ 1 ] [ 2 ] In a semiconductor laser , the optical pulses are generated by injecting many carriers ( electrons ) into the active region of the device, bringing the carrier density ...
The active laser medium (also called a gain medium or lasing medium) is the source of optical gain within a laser. The gain results from the stimulated emission of photons through electronic or molecular transitions to a lower energy state from a higher energy state previously populated by a pump source. Examples of active laser media include: