摘要:
Vertical-cavity surface-emitting lasers (VCSELs) are disclosed having various intra-cavity structures to achieve low series resistance, high power efficiencies, and TEM mode radiation. In one embodiment of the invention, a VCSEL comprises a laser cavity disposed between an upper mirror (70) and a lower mirror (20). The laser cavity comprises upper spacer (50) and lower spacer (30) layers sandwiching an active region (40). A stratified electrode (60) for conducting electrical current to the active region (40) is disposed between the upper mirror (70) and the upper spacer (50). The stratified electrode (60) comprises a plurality of alternating high and low doped layers (62, 63, 64) for achieving low series resistance without increasing the optical absorption. The VCSEL further comprises a current aperture as a disk shaped region formed in the stratified electrode for suppressing higher mode radiation. The current aperture is formed by reducing or eliminating the conductivity of the annular surrounding region. In another embodiment, a metal contact layer having an optical aperture is formed within the upper mirror of the VCSEL. The optical aperture blocks the optical field in such a manner that it eliminates higher transverse mode lasing.