Emission wavelength setting of 1310nm-waveband VCSELs designed for coarse wavelength division multiplexing (CWDM) 4x10 Gbps fiber-optics transmission can be controlled thanks to the wafer fusion fabrication approach. This approach allows performing the cavity adjustment before bonding the distributed Bragg reflectors (DBRs) to the active cavity of the device. Cavity adjustment was performed by digital etching with nanometer precision and proves to be very effective in compensating for epitaxial growth thickness off-set relative to nominal design and thickness nonuniformity across the wafer. With this fabrication approach we reach on fused VCSEL wafers more than 90% yield of devices that fit the CWDM wavelength slots. © 2014 SPIE.