emiconductor lasers, which emit from surfaces formed by cleaving the individual chip out of a wafer [14]. There are several advantages to producing VCSELs when compared with the production process of edge-emitting lasers. Edge-emitters cannot be tested until the end of the production process. If the edge-emit- ter does not work the production time, the processing materials and especially the test cost in term of manpower have been wasted. On the contrary, VCSELs can be tested at several stages throughout the process to check for material quality and processing issues. Additionally, because VCSELs emit the beam perpendicular to the active region of the laser as opposed to parallel as with an edge emitter, tens of thousands of VCSELs can be processed simultaneously on a 3-in. wafer. Furthermore, even though the VCSEL production process is more labor- and material- intensive, the yield can be controlled to a more predictable outcome. The VCSEL laser resonator consists generally of two distributed Bragg reflectors (DBRs) parallel to the wafer surface obtained alternating deposited layers of different materials. The active region consists of one or more quantum wells allowing the control of both the threshold current, which in this kind of laser design can get very high if the laser is not designed carefully, and the emitted wavelength through the quantum well's structure. The planar DBR mirrors consist of layers with alternating high and low refractive indi- ces. Each layer has a thickness of a quarter of the laser wavelength in the material, yielding intensity reflectivity above 99%. High reflectivity mirrors are required in VCSELs to bal- ance the short axial length of the gain region. In common VCSELs the upper and lower mirrors are doped as p-type and n-type mate- rials, forming a diode junction. In more complex structures, the p-type and n-type regions may be buried between the mirrors, requiring a more complex semiconductor process to make electrical contact with the active region, but eliminating electrical po