Performance comparison of 850-nm and 1550-nm VCSELs exploiting OOK, OFDM, and 4-PAM over SMF/MMF links for low-cost optical interconnects

► We study a 850-nm and a 1550-nm VCSEL for optical interconnects. ► OFDM-QPSK/16QAM, 4-PAM are compared to substitute OOK in short-reach SMF/MMF links. ► Strong potential of OFDM for employment in future optical interconnects is shown. ► Reach limits of OOK, OFDM, and 4-PAM, over SMF and MMF links is investigated. ► Point-to-point links are compared to OSMOSIS, an all-optical permutation switch.