QAM-GFDM of Dual-Mode VCSEL Mixed 28-GHz MMW Carrier for Fiber-Wireless Link

An optical heterodyned 28-GHz carrier generation is demonstrated for synthesizer-free fifth-generation (5G) millimeter wave over fiber (MMWoF) link by using orthogonally polarized dual-mode vertical-cavity surface-emitting laser (VCSEL) as the frontend transmitter, and the power envelope detection is employed for self-heterodyne down-conversion of the generalized frequency division multiplexing (GFDM) data stream. The demonstrated MMWoF link exhibits superior immunity to the residual frequency and phase noises as well as the inter-carrier interference induced by the free-running dual-mode carrier. For back-to-back optical downstream wireline transmission, the receiving GFDM data optimizes its bit error rate (BER) to 2.2×10 −4 by adjusting the bias current of the dual-mode VCSEL to 8 mA (3 I th ), and by grouping the GFDM data matrix with total symbols of N = K×M with K = 2 subcarriers and M = 24 timeslots. After a long-reach delivering the optical data stream over 50-km dispersion-managed single-mode fiber (DM-SMF), the qualified receiving power sensitivity is −12 dBm, whereas the decoding GFDM data reveals improved receiving sensitivity with an extremely low power penalty of only 0.3 dB. For the wireless transmission after optical downstream receiving at the remote node, the self-heterodyned MMW carrier exhibits peak power of −62.3 dBm and carrier-to-noise (CNR) of 26.8 dB over long-reach 50-km DM-SMF downstream optical link. In comparison with the mutual heterodyned from two incoherent optical carriers, the self-heterodyned frequency fluctuation can be suppressed from >500 to