We report on the generation and transmission of a millimeter-wave (MMW) signal with a frequency of 28 GHz by employing an InAs/InP quantum-dash dual-wavelength laser diode (QD-DWL) emitting in the ~1610 nm extended L-band window. The self-injection locking (SIL) technique has been engaged to improve the linewidth and reduce the noise of the optical tone. Besides, the transmission of a 2 Gbits/s quadrature phase-shift keying (QPSK)-modulated 28-GHz MMW beat tone over a hybrid 20-km radio-over-fiber combined with 5-m radio-over-free-space-optics and up to 6-m radio frequency wireless link has been demonstrated. Moreover, comparing the proposed QD-DWL with a commercial laser showcased similar performance characteristics, making the QD-DWL a candidate source for MMW applications.
