Wavelength & mm-Wave Flexible Converged Optical Fronthaul With a Low Noise Si-Based Integrated Dual Laser Source

A widely tunable hybrid InP-Si
₃
N
₄
dual laser module (DLM) with low linewidth and relative intensity noise (RIN) is used to develop a wavelength and frequency flexible optical fronthaul system for high-capacity wireless networks. The wavelength flexible (over C-band) delivery of 5G signals over an analog radio-over-fiber (A-RoF) system, incorporating wireless transmission at 60 GHz is demonstrated. A phase noise (PN) and frequency offset (FO) cancelling receiver is used to overcome phase/frequency noise from the DLM due to thermal fluctuations, and this reduces the received (error vector magnitude) EVM to as low as 5%. Using the same DLM we demonstrate the mm-wave frequency flexible (over sub-V-band) delivery of 5G and WiGig signals over a simplified converged fronthaul link. The experimental results show excellent performance with bit error ratio (BER) values as low as 8.46×10
^-6
and 1.11×10
^-4
, and lowest EVMs of 2.4% and 6.1%, achieved for sub-V-band 5G and WiGig signals, respectively. In addition to highlighting the high flexibility of the DLM, this work also presents an approach to deploy this source in future optical-wireless access networks paving way for beyond 5G and 6G technologies.