Chip-scale remote radio head interface for full-duplex coherent optical wireline-wireless network: Leveraging coherent mobile fronthauling through analogue opto-electronics

摘要

A novel remote radio head interface facilitating wireless-wireline integration in optical fronthaul networks is proposed and experimentally evaluated. In particular I show bidirectional coherent analogue optical radio signal transmission with a single photonic laser device for the first time. The injection locking capability utilized for the externally modulated laser enables precise opto-electronic translation of the radio carrier frequency, even in presence of wavelength emission drift of light sources. Proof-of-concept is made for radio downlink signals with up to 1-GHz bandwidth. The simplicity of the mobile fronthaul interface is guaranteed by the sufficiency of the coherent detection scheme that does not depend on optical-layer digital signal processing as required in state-of-the-art coherent optical systems. I demonstrate full-duplex transmission of 100-MHz 64-ary quadrature amplitude modulated orthogonal frequency division multiplexed signals through frequency division duplex. The performance is experimentally validated at low error vector magnitudes of 5.3% over a 27.5 km reach, 1:128 split network.