Stable single-mode 850 nm VCSELs with a higher-order mode absorber formed by shallow Zn diffusion

We report that an 850 nm VCSEL with a planar higher-order mode absorber formed by shallow Zn diffusion (<0.3 /spl mu/m deep) operated at stable single-mode. A 5 /spl mu/m square device showed single-mode emission with a /spl sim/ 0.8 mA threshold, a 2.2 mW maximum output power, and a mode suppression ratio of 40 dB.