Reduction of absorption losses in MOVPE-grown AlGaAs Bragg mirrors.

ABSTRACT

Residual p-type doping from carbon has been identified as the root cause of excess absorption losses in (Al)GaAs/AlGaAs Bragg mirrors for high-finesse optical cavities when grown by metalorganic vapor phase epitaxy (MOVPE). Through optimization of the growth parameters with the aim of realizing low carbon uptake, we have shown a path for decreasing the parasitic background absorption in these mirrors from 100 to the 10 ppm range near 1064 nm. This significant reduction is realized via compensation of the carbon acceptors by intentional doping with the donor silicon in the uppermost layer pairs of 40-period GaAs/AlGaAs Bragg mirrors. Thus, we find that such compensation enables MOVPE-derived multilayer mirrors with the potential for a high cavity finesse (>100,000 in the near infrared) approaching the performance levels found with Bragg mirrors grown by molecular beam epitaxy (MBE).