Intracavity contacts for low-threshold oxide-confined vertical-cavity surface-emitting lasers

Very low threshold vertical-cavity surface-emitting lasers are demonstrated using intracavity contacts, an upper dielectric Bragg reflector, and an un doped lower AlAs-GaAs Bragg reflector. The undoped lower mirror allows the demonstration of the highest differential efficiency yet achieved for sub-1 00-mu A threshold, which is 60% for a 67-mu A threshold. Devices with small er output coupling show threshold current densities as low 98 A/cm(2), and a minimum threshold current of 23 mu A for a small aperture.