laser diode


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laser diode

[′lā·zər ¦dī‚ōd]

laser diode

A semiconductor-based laser used to generate analog signals or digital pulses for transmission through optical fibers. Both laser diodes and LEDs (light-emitting diodes) are used for this purpose, but the laser diode generates a smaller beam that is easier to couple with the smaller core of singlemode fibers. Laser diodes are designed to emit light either from their edge or their surface, the latter providing a circular beam that couples better with the round core of the fiber.

Laser diodes work on the same principle as the bigger gas lasers. They function as an optical oscillator by stimulating a chain reaction of photon emission inside a tiny chamber. In edge-emitting lasers, the semiconductor waver is cleaved, and the inherent properties of the semiconductor create reflective ends that may or may not be enhanced with additional reflective films. With vertical cavity surface emitting lasers (VCSELs), the reflectivity has to be added.

The most common semiconductors used in laser diodes are compounds based on gallium arsenide (750 to 900 nm in the infrared), indium gallium arsenide phosphide (1200 to 1700 nm in the infrared) and gallium nitride (near 400 nm in the blue). See laser and solid state laser.


Laser Diodes
Laser diodes such as these are all fabricated using semiconductor processes just like CPU and memory chips. Note that the VCSELs (vixels) produce a circular beam that couples well with a fiber.







A Tunable Laser Diode
Laser diodes also make great sensors. This laser diode from Jet Propulsion Labs is tunable to different frequencies in order to detect various gases both on this and other planets. (Image courtesy of JPL's Microdevices Laboratory; Robert M. Brown, photographer)
References in periodicals archive ?
As firms committed to laser diode R&D, it became clear that the laser diode would find applications in optical data storage such as video discs, compact discs, and laser discs.
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When operating single emitter laser diodes, the high-resolution currents reach voltages of up to 120V.
In a textbook style but without a lot of strict technicalities, Trestman explains the design and skilled use of laser diode drivers and power supplies for the electrical components of laser diode systems.
BEA Lasers (Elk Grove Village, IL) introduces two new low profile additions to their rugged MIL Series of laser diode modules.
Figure 4 shows the lasing emission spectra of the laser diode measured under CW operation at room temperature with the current of 150 mA, 180 mA, and 200 mA, which consist of multiple longitudinal modes.
IMM Photonics has expanded its existing range of laser diode modules by adding a series of green laser diode modules with output power of 0.9 and 5 mW.
Technavio's analysts forecast the global laser diode market to grow at a CAGR of 11.07% during the period 2016-2020.

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