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In order to achieve ultrahigh data capacity and to overcome the wireless spectrum crunch, 5G is going to adopt millimeter-wave (mmW) frequencies (30 GHz – 300 GHz). To generate high-quality mmW signals by lasers, it requires optical sources with ultra-narrow optical linewidth and low relative intensity noise (RIN). In recent years, we have developed InAs/InP quantum dot (QD) multi-wavelength lasers (MWLs) around 1550 nm with the frequency spacing from 10 GHz to 1000 GHz. Those QD MWLs have very low RIN, ultra-narrow optical linewidth, small timing jitters, compact size, low power consumption and the ability for hybrid integration with silicon substrates. In this paper we present a buried heterostructure (BH) C-band InAs/InP 25-GHz QD MWL with phase noise and RIN of less than 500 kHz and -130 dB/Hz for its individual channel, respectively. By using this QD MWL a photonic aided radio-over-fiber (RoF) quadrature amplitude modulated (QAM) signal wireless delivery at 25 GHz is successfully demonstrated through 25.22 km standard single-mode fiber (SSMF) with a data capacity of 16 Gbit/s (16QAM x 4GBaud). We have also presented a monolithic BH QD dual-wavelength (DW) DFB laser as an optical beat source for mmW signal generation. The BH QD DW-DFB laser with the optical linewidth of 16 KHz and the RIN of -158 dB/Hz is capable of generating spectrally pure mmW signals between 46 GHz and 48 GHz. By using it, we have demonstrated a real time 24-Gbit/s (64QAM x 4GBaud) data bandwidth wireless communication system operating at 47.2-GHz carrier over 25-km SSMF.
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