Tunable Mm-Wave A-RoF Transmission Scheme Employing an Optical Frequency Comb and Dual-Stage Active Demultiplexer

Anovel dual-stage optical frequency comb (OFC) demultiplexer, for use in a photonic millimeter-wave (mmW) generator, is demonstrated. Unlike other demultiplexing techniques, the proposed method features a single optical path for both tones used for the mmW generation, thus eliminating the challenges related to the mismatch of path lengths. In addition, the use of active demultiplexing provides filtering, amplification and data modulation of the comb tones, all in a single device. In this article, we demonstrate the operational principle of the dual-stage active demultiplexer-enabled mmW generation, verify the quality (beat tone width ∼13 Hz) and stability (power fluctuation ∼0.26 dB) of the generated mmW signal and validate the performance of an A-RoF system employing the proposed device. For the system demonstration, 64-QAM UF-OFDM signals, at frequencies of 29.5 and 38 GHz, are generated and transmitted over 25 km of single-mode fiber. A BER of 3.2e-4 for 29.5 GHz and 1.6e-4 for 38 GHz is achieved without the use of optical amplifiers, showing the great potential of the proposed technique. Finally, a case study of an A- RoF distribution system, employing three different demultiplexing techniques, is presented. We demonstrate that the proposed transmitter, in comparison to other demultiplexing techniques, provides a larger power budget (> 6 dB) that can be used to extend the reach of the system and/or increase the number of remote radio units served using a single OFC.