Single-Mode Vertical-Cavity Surface-Emitting Laser Array With High Power and Narrow Far-Field Divergence Angle

We demonstrate novel structures of an 850-nm vertical-cavity surface-emitting laser (VCSEL) array for high output power, single-lobe far-field pattern, and narrow divergence angle. By using the Zn-diffusion process with proper sizes of oxide-current-confined and Zn-diffusion apertures, each unit of VCSEL in the demonstrated array is highly single-mode (side-mode suppression ratio
$>$
30 dB) with a narrow far-field divergence angle
$(9^{\circ}$
–
$10^{\circ})$
and high maximum single-mode output power (
$\sim$
6.3 mW). Due to the high uniformity of single-mode performance of each VCSEL unit, the 6
$\times$
6 array exhibits an excellent lasing phenomenon, which includes single-lobe far-field pattern, weak in-phase coupling, narrowing of divergence angle (from 9
$^{\circ}$
to 4
$^{\circ}$
), and output power as high as around 104 mW. Furthermore, by measuring the bias-dependent output optical spectra in different positions of our array, the high similarity of these spectra indicates the excellent uniformity of our fabrication process for single-mode VCSEL.