Ivana Gasulla

Performance of Direct-Detection Mode-Group-Division Multiplexing Using Fused Fiber Couplers

We present an end-to-end performance evaluation of a mode-group-division multiplexing system that uses direct detection instead of coherent detection, avoiding complex digital signal processing. The system transmits four data channels through a step-index fiber supporting six spatial modes comprising four mode groups, considering the twofold degeneracy of the LPlm modes for l ≠ 0. Multiplexing and demultiplexing is performed using two- and three-core fused fiber couplers, each one phase-matched to a group of degenerate modes. These devices are analyzed through a field-based model that describes, for the first time to our knowledge, crosstalk between all the fiber modes. Propagation through the few-mode fiber is modeled considering differential modal attenuation, intermodal dispersion, chromatic dispersion, and both intergroup and intragroup modal coupling. The end-to-end link is described by a concatenation of matrix operators describing the optical field transfer functions for the multiplexer, fiber, and demultiplexer. Error-free transmission of four 32-Gb/s OOK-modulated data channels through a 1-km link proves the feasibility of the proposed direct-detection mode-group-division multiplexing approach.

Analog Filtered links: A unifying approach for Microwave Photonic systems

The concept of Analog Filtered links recently proposed is revisited with a view of providing a unifying modelling approach of the different applications of Microwave Photonics systems. We illustrate its application to filtering, optical beam-forming, RoF systems, optoelectronic oscillators and Analog to Digital converters.

RF photonic delay lines using space-division multiplexing

We review our last work on dispersion-engineered heterogeneous multicore fiber links designed to act as tunable true time delay lines for radiofrequency signals. This approach allows the realization of fiber-distributed signal processing in the context of fiber-wireless communications, providing both radiofrequency access distribution and signal processing in the same fiber medium. We show how to design trench-assisted heterogeneous multicore fibers to fulfil the requirements for sampled true time delay line operation while assuring a low level of crosstalk, bend sensitivity and tolerance to possible fabrication errors. The performance of the designed radiofrequency photonic delay lines is evaluated in the context of tunable microwave signal filtering and optical beamforming for phased array antennas.

Reconfigurable integrated waveguide meshes for photonic signal processing and emerging applications

We review the recent advances reported in the field of integrated photonic waveguide meshes, both from the theoretical as well as from the experimental point of view. We show how these devices can be programmed to implement both traditional signal processing structures, such as finite and infinite impulse response filters, delay lines, beamforming networks as well as more advanced linear matrix optics functionalities. Experimental results reported both in Silicon and Silicon Nitride material platforms will be presented. We will also discuss the main programming algorithms to implement these structures and discuss their applications either as standalone systems or as part of more elaborated subsystems in microwave photonics, quantum information and machine learning.

Sampled Microwave Photonic delay lines using heterogeneous multicore fibers

We propose, for the first time to our knowledge, the application of multicore fibers (MCFs) to the implementation of sampled optical delay lines for RF signals. Heterogeneous multicore fibers are addressed as a generic building block and discussion is then centered on the particular application of arbitrary waveform generation.

Noise Figure of Slow Light Cascaded SOA based Microwave Photonic Phase Shifters

The noise figure of Slow and Fast Light Microwave Photonic phase shifters made up by SOA followed by optical filtering stages is experimentally evaluated. Noise figure results show compression when adding the third cascaded stage.

Microwave Photonics Applications Using Slow and Fast Light Effects

We review the potential applicability of SFL techniques to the field of Microwave photonics. The main results obtained for several applications such as filtering, phased array antennas, arbitrary waveform generation and OEO will be analyzed.