Optical Linewidth Tolerant mmW Generation Employing a Dual-Stage Active Demultiplexer

Abstract

In this letter, we propose a novel linewidth tolerant millimetre-wave (mmW) generation scheme employing a dual-stage active demultiplexer and an optical frequency comb (OFC). A unique feature of this architecture is that the two heterodyned tones travel the same path, alleviating the challenges associated with mismatches in the path lengths. We analyse the influence of the path length difference and source linewidth on the purity of the generated mmW signal and verify the tolerance, of the proposed scheme, to the optical linewidth. In addition, an experimental investigation of the performance of a 64 QAM discrete multitone (DMT) analog-radio over fibre (A-RoF) distribution system operating at 37.5 GHz using the proposed architecture, is presented. A BER below the HD-FEC limit is achieved, after 25 km fibre transmission, when employing an OFC with linewidth of ~30 kHz and ~3.1 MHz. Moreover, no significant performance penalty (at the HD-FEC limit) is observed due to an increase in the OFC linewidth, highlighting the linewidth tolerance of the proposed system.