A Monolithic Integrated Microwave Photonics Filter
  Meeting the ever increasing demand for transmission capacity in wireless networks will require evolving towards higher regions in the radiofrequency spectrum, reducing cell sizes as well as resorting to more compact, agile and power efficient equipment at the base stations, capable of smoothly interfacing the radio and fiber segments. Photonic chips with fully functional microwave photonic systems are promising candidates to achieve these targets. Over the last years, many integrated microwave photonic chips have been reported in different technologies. However, and to the best of our knowledge, none of them have fully integrated all the required active and passive components. Here, we report the first ever demonstration of a microwave photonics tunable filter completely integrated in an Indium Phosphide chip and packaged. The chip implements a reconfigurable RF- photonic filter, it includes all the required elements, such as lasers, modulators and photodetectors, and its response can be tuned by means of control electric currents. This demonstration is a fundamental step towards the feasibility of compact and fully programmable integrated microwave photonic processors. 
Javier S. Fandi\~no, Pascual Mu\~noz, David Dom\'enech, Jos\'e Capmany
physics.optics