Single-Mode 850-nm VCSELs for 54-Gb/s ON–OFF Keying Transmission Over 1-km Multi-Mode Fiber

By combing Zn-diffusion and oxide-relief apertures with strong detuning (>20 nm) in our demonstrated short-cavity (λ/2) 850-nm vertical-cavity surface-emitting lasers (VCSELs), wide electrical-to-optical bandwidth (29-24 GHz), low-differential resistance (~100 Q), and (quasi) single-mode (SM) with reasonable output power (~1.4 mW) performances can be simultaneously achieved. Error-free ON-OFF keying transmission at 54-Gb/s data rate through 1-km OM4 multi-mode fiber can be achieved by using highly SM device with forward error correction and decision feedback equalization techniques. As compared with the reference device with a larger oxide-relief aperture and a multi-mode performance, the SM device exhibits lower bit-error rate (1 × 10
^-5
versus 1 × 10
^-2
) at 54 Gb/s. This result indicates that modal dispersion plays more important role in transmission than that of output power does. We benchmark these results to an industrial 50-Gb/s SM VCSEL. It shows a higher bit-error-rate value ~3.5×10
^-3
versus ~1.4×10
^-4
under the same received optical power.