Abstract
The effects of epitaxis SiO2 film on the characteristics of DBR reflectivity were simulated, and the reflectivity of graded interface DBR is lower than the abrupt one was studied. 850nm vertical-cavity surface-emitting lasers were fabricated, the DBR is formed by graded heterojunction of AlxGa1–xAs, the top and bottom DBR have 22 and 34 pairs of mirror, and current was confined by oxide aperture, and then different thickness of SiO2 film were grew on the top DBR. and found that a certain thickness (λ/4) of the SiO2 reflection reducing coating could make the vertical-cavity surface-emitting lasers output power increased about 3–5 mW, the threshold current does not increase obviously, the reason is external quantum efficiency increases more than the threshold current. So the SiO2 reflection reducing coating does not affect the lasing of lasers and threshold current obviously, but It can significantly improve the output power. The experimental results agree well with the theoretical expectation.
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