VCSELs with enhanced single-mode power and stabilized polarization for oxygen sensing

Vertical-cavity surface-emitting lasers (VCSELs) with a single-mode single-polarization emission at a wavelength of approximately 763 nm have become attractive for oxygen sensing. Up to now, VCSELs used for this application are single-mode because of a small active diameter which correspondingly leads to small optical output power. Employing the surface relief technique and in particular the surface grating relief technique, we have increased the single-mode output to more than 2.5 mW averaged over a large device quantity. To the best of our knowledge, this is the highest single-mode power ever reported for VCSELs in this wavelength range. Through the grating relief simultaneously, we were able to stabilize the light polarization.