Enhancing the Static and Dynamic Performance of High-Speed VCSELs by Zn-Diffused Shallow Surface Relief Apertures

In this paper, we demonstrate a novel structure for 850- and 940-nm wavelength high-speed vertical-cavity surface-emitting lasers (VCSELs). Extra shallow apertures (~20 nm) are etched on the topmost current spreading (CS) layer of 850- or 940-nm VCSELs, which have Zn-diffusion and oxide-relief apertures inside. Such a structure simultaneously allows a significant enhancement of the output power and a reduction in the number of optical modes in the optical spectrum, which migrates toward the quasi-single-mode (QSM). Comparison is made to multi-mode (MM) reference VCSELs produced without etching of the CS layer. The etched devices exhibit a larger signal-to-noise ratio for error-free 32 Gbit/s transmission over 100-m MM fibers (MMFs) at both wavelengths (850 and 940 nm). In addition, the dynamic/static performance of the etched samples is also superior to that of a QSM reference sample, produced by utilizing only Zn-diffusion apertures without etching of the CS layer. The demonstrated device structure opens the door to greatly improve the performance of SM and high-power VCSELs for high-speed data transmission.