Optical Generation of mmW and THz Signals Using PICs

As the demand for wireless data transmission increases, there is a push towards the adaptation of new spectral bands, which can provide the required capacity to satiate this demand. These include millimeter wave (mmW) and even terahertz (THz) signals. One of the main challenges faced at such extremely high frequencies, is the generation and manipulation of the signals. Since the electronic approach suffers from low efficiency and high losses, the photonic generation of the mmW and THz signals becomes increasingly attractive. In this paper, we demonstrate a photonically-integrated device capable of generating an optical frequency comb (OFC), which in turn could be used for the optical generation of high-frequency (mmW and THz) signals. A complete OFC characterisation, to demonstrate the performance and the limitations of the device, in terms of the frequency tuning range and the spectral quality of the generated signal, will also be presented. Finally, methods that could be used to expand the frequency comb, in order to generate THz frequencies will also be discussed.