From Understanding Lasers

9.6 EDGE-EMITTING DIODE LASERS

Diode laser resonators can be constructed in a number of ways. A logical way to group the various types of laser resonators is by their orientation relative to the active layer where the stimulated emission is generated.

Early diode lasers resonated in the plane of the junction layer, as shown in Figures 9-7 and 9-11. These lasers are called edge emitters because their output comes from the active layer at the edge of the laser chip. Their advantage is that they can extract laser gain from the length of the laser chip, typically a few hundred micrometers, to produce relatively high power. They take a few different forms.

An important alternative is the surface-emitting laser, in which the beam emerges from the surface of the chip. Surface emitters have other advantages in beam quality and come in two basic variations: vertical-cavity lasers that oscillate perpendicular to the junction layer, and hybrid lasers that oscillate in the junction plane but direct output through the surface. You will learn more about these types in Section 9.7.

© 2008

Products & Services
Diode Lasers
Diode lasers use light-emitting diodes to produce stimulated emissions in the form of coherent light output. They are also known as laser diodes.
Laser Mounts
Laser mounts are devices that keep a laser in position on an optical table.
Fiber Lasers
Fiber lasers use optical fibers doped with low levels of rare-earth halides as the lasing medium to amplify light.
Lasers
Lasers are devices that produce intense beams of monochromatic, coherent radiation. The word "laser" is an acronym for Light Amplification by Stimulated Emission of Radiation.
Light Emitting Diodes (LED)
Light-emitting diodes (LED) are PN junction devices that give off light radiation when biased in the forward direction. LEDs are used in a wide variety of indication applications.

Topics of Interest

The simplest type of diode laser resonator is the Fabry Perot cavity introduced in Chapter 3, a linear cavity with flat mirrors on the two ends. In a semiconductor laser, the linear cavity is the...

9.14 WHAT HAVE WE LEARNED? Semiconductor lasers are often called diode lasers or laser diodes. Diodes are two-terminal electronic devices that conduct current in one direction. Electrons in the...

9.3.2 Semiconductor Diode Laser Concepts It was a surprisingly small step from the first efficient LEDs to the first semiconductor lasers. Both were demonstrated in 1962 in the same material, gallium...

9.5 CONFINEMENT IN THE JUNCTION PLANE The first diode lasers produced recombination energy and light across the entire junction plane. One of the refinements needed to allow continuous operation at...

9.7.1 Vertical-Cavity Surface-Emitting Lasers (VCSELs) Vertical-cavity surface emitting lasers (VCSELs) get their name because their resonant cavities are vertical, perpendicular to the active layer,...