Tunable optical delay line based on single-sideband suppressed-carrier modulation

J. Palaci, B. Vidal
2013 IEEE Photonics Technology Letters  
The processing of radiofrequency signals using photonics means is a discipline that appeared almost at the same time as the laser and the optical fibre. Photonics offers the capability of managing broadband radiofrequency (RF) signals thanks to its low transmission attenuation, a variety of linear and non-linear phenomena and, recently, the potential to implement integrated photonic subsystems. These features open the door for the implementation of multiple functionalities including optical
more » ... sportation, up and down frequency conversion, optical RF filtering, signal multiplexing, de-multiplexing, routing and switching, optical sampling, tone generation, delay control, beamforming and photonic generation of digital modulations, and even a combination of several of these functionalities. This thesis is focused on the application of vector processing in the optical domain to radiofrequency signals in two fields of application: optical beamforming, and photonic vector modulation and demodulation of digital quadrature amplitude modulations. The photonic vector control enables to adjust the amplitude and phase of the radiofrequency signals in the optical domain, which is the fundamental processing that is required in different applications such as beamforming networks for direct radiating array (DRA) antennas and multilevel quadrature modulation. DRAs consist of a set of individual antenna elements working simultaneously as an array antenna with an equivalent electrical size of a bigger single antenna. All the antenna elements radiate the same signal and, when all this signals interfere in the far-field, a constructive interference is achieved at a certain angular direction. Conventional implementations in the digital or microwave domain can show a high degree of complexity of the beamforming networks (i.e. the subsystem that performs the signal splitting and the phase and amplitude control) since it increases dramatically with the size of the antenna impacting in their size, mass, volume, v
doi:10.1109/lpt.2012.2227697 fatcat:e5uasvwjd5ckvcllvynughtbg4