Reconfigurable multi-band radio-frequency transceiver based on photonics technology for future optical wireless communications

This study presents the concept and the implementation of a fully photonics-based and reconfigurable multi-band radio-frequency (RF) transceiver for future optical-wireless communications networks. The proposed device is based on frequency multiplication using optical external modulation technique, which enables to achieve discrete tuning of the wireless frequency by simply manipulating the modulator bias voltage. The physical mechanism behind the frequency multiplication is analytically explained and experimentally demonstrated by generating RF carriers at 5.2 GHz with signal-to-noise ratio of up to 54 dB. High spectral purity, distortion absence and low phase noise of the generated RF signals have been observed. Furthermore, the photonics-based reconfigurable RF transceiver has been implemented and tested in a real optical-wireless network from the telecom operator Telecom Italia Mobile using a femtocell base station. Data transmission and a high-quality voice call have been realised using the proposed approach in order to illustrate its applicability.