Duplex Millimeter-Wave Over Fiber Link Using an InAs/InP Quantum-Dash Mode-Locked Laser

We experimentally demonstrate a duplex millimeter-wave-over-fiber (MMWoF) link for duplex wireless communications using a free-running InAs/InP quantum-dash passively-mode-locked laser (QD-MLL) as a light source. The QD-MLL is able to generate a frequency comb with a comb spacing of 0.2 nm (25.08 GHz). In the downlink, a microwave vector signal at 3 GHz is modulated on one comb line and transmitted with an adjacent comb line to a remote radio unit over a 10-km single-mode fiber. After detection at a photodetector, a microwave vector signal at an up-converted frequency of 28 GHz is generated and radiated to achieve 2-m wireless transmission. In the uplink, a microwave vector signal at 28 GHz is down converted to 3 GHz and modulated on a reused comb line and transmitted to the central office over the same fiber link. The performance in terms of the error vector magnitudes and bit error rates is evaluated experimentally.