Ubiquitous satellite communications are in a leading position for bridging the digital divide. Fulfilling such a mission will require satellite services on par with fibre services, both in bandwidth and cost. Achieving such a performance requires a new generation of communications payloads powered by large-scale processors, enabling a dynamic allocation of hundreds of beams with a total capacity beyond 1 Tbit s −1 . The fact that the scale of the processor is proportional to the wavelength of its signals has made photonics a key technology for its implementation. However, one last challenge hinders the introduction of photonics: while large-scale processors demand a modular implementation, coherency among signals must be preserved using simple methods. Here, we demonstrate a coherent photonic-aided receiver meeting such demands. This work shows that a modular and coherent photonic-aided payload is feasible, making way to an extensive introduction of photonics in next generation communications satellites.

Development of left ventricular to coronary sinus fistula is a rare complication of mitral valve surgery. Three of the seven previously reported cases occurred following multiple valve replacement surgeries, all of which were thought to be secondary to a complication of surgery and all were treated with surgical closure of the fistula. We report a case of left ventricular to coronary sinus fistula occurring after two mitral valve replacement surgeries that was treated medically with favorable long-term results.

We review the guided-wave subcomponents required in the design of high-functionality modulators for advanced modulation formats using the GaAs/AlGaAs material system. In these complex devices, small loss contributions rapidly accumulate unless the substructures are well optimized, not only for low loss but also for process tolerance. Results for an advanced 40-Gb/s DQPSK modulator are presented.

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The design and dimensioning of a photonic-aided payload for a multi-beam high-throughput communications satellite is a complex problem in which the antenna, RF and photonic subsystems must be considered as a whole for achieving best performance with lowest mass and power consumption. In this paper, we propose and dimension the receiving stage of a communications satellite comprising a phased array antenna (PAA) feeding a multibeam photonic beamforming system (PBS). The PBS uses a single wavelength and resorts to heterodyne detection such that the retrieved beams are frequency downconverted. End-to-end system modeling shows that the complexity of the PAA and PBS can be traded-off for signal-to-noise ratio (SNR) or power consumption without compromising the beam width. The dimensioning of a realistic scenario is presented, showing that an SNR and beam crosstalk on the order of 20 dB are achievable with a total power consumption below 1 kW for a typical number of 100 antenna elements (AEs).