60 GHz radio signal up-conversion and transport using a directly modulated mode-locked laser

Abstract

In this paper, we perform a frequency up-conversion from 4.5 GHz to 60 GHz of an OFDM signal compliant to the IEEE802.15.3c pre-standard (3.03 Gbps) by directly modulating a Fabry-Pérot Mode-Locked Laser whose self-pulsating frequency is 54.8 GHz. Improved performance compared to the external modulation scheme previously reported is achieved and comparison with the use of a standard electronic up-converter shows only a slight degradation. The direct modulation represents a major improvement in terms of set-up simplicity and improves the efficiency of the conversion process. It does not degrade the phase noise properties of the photonic oscillator. This simple set-up allows as well the distribution (over 50 m) of the 60 GHz radio signal using radio-over-fibre. Transmission of the up-converted signal over 5 m of air does not show any significant degradation.