ABSTRACT
The vertical cavity surface emitting laser (VCSEL) is a semiconductor laser which has a resonant cavity that is vertically formed with the surfaces of epitaxial layers. The VCSEL is being applied in various optical systems such as optical fiber networks, parallel optical interconnects, laser printers, and high density optical disks. This chapter summarizes the physical difference between VCSELs and conventional stripe geometry lasers. A VCSEL has a linear polarization. This is due to a small amount of asymmetric loss coming from the shape of the device or material. Some optical confinement schemes were developed for VCSELs. The fundamental concept is to increase the overlap of optical field with gain region. The initial motivation of surface-emitting laser invention was fully monolithic fabrication of laser cavity. The VCSEL structure may provide a number of advantages such as: laser devices can be fabricated by a fully monolithic production with a very high yield, wide and continuous wavelength tuning is possible, and so on.
