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Inverters based on power switches, such as IGBTs, in either resonant or hard-switching topologies can, during or after a load-fault, exhibit a transient overvoltage at the collector-emitter leads. In such an event, the maximum allowed collector-emitter voltage may be exceeded and the power switch destroyed. To avoid this, some form of active clamping may be used. In this work, we present a concept of a single possibly co-packed, high-voltage TVS-diode with typical breakdown voltages ranging from 1.2 to 1.7 kV.

The desaturation and charge recovery behavior for 1200-V RC-IGBTs with diode control is investigated. The low thickness of the drift-region of modern 1200-V IGBTs results in significantly reduced time constants of the diode-control feature. While a low desaturation time constant is well acceptable, the recovery time constant becomes critical when compared to typical locking time requirements of common gate driver units. The impact of different locking times on the overall performance is discussed and a novel device concept for RC-IGBTs is presented which overcomes this issue. The FWD-mode of the novel RC-IGBT is desaturated at a gate-emitter voltage of 0 V allowing for the first time a desaturation pulse pattern which may disregard the locking time requirements of the driving-unit.

The development of Si-based photonics has been far behind the development of electronics for long time. There are two reasons for that. As silicon is an indirect band gap semiconductor, achieving light emission and gain is quite difficult. On the other hand, for using silicon as a light guiding material for passive devices, the main constrains until recently were relatively high propagation losses and high fiber-to-waveguide incoupling losses. The general trend towards more compact photonic devices together with progress in fabrication techniques resulted in the development of two nano-photonic technologies for next generation optical devices: photonic crystals and nanowire waveguides-based devices. To drastically increase the integration density and achieve subwavelength confinement of light along the propagation direction, plasmonic waveguides have been proposed. Surface plasmons are electromagnetic modes constituted on the interface between a metal and a dielectric. The tradeoff between the light confinement and propagation loss has here a vital importance.

The main objective of the research towards high density optical integration is to realize ultra-dense optical planar integrated circuits that combine passive and active optical functionalities as well as electronics playing control and logic functions. The most desirable output would be to have available for a designer a set of monolithically integrated building blocks incorporating all the necessary optical and electronic functions upon a single silicon substrate. Here we will present some of the contributions made towards highly integrated photonic circuits by a collaborative groups of the Joint Research Center of Photonics of the Royal Institute of Technology and Zhejiang University: directional coupler wavelength selective filter based on dispersive ID Bragg reflection waveguide, vertically coupled photonic crystal filter], compact arrayed waveguide grating demultiplexer based on amorphous silicon nanowires and polarization beam splitter based on two-dimensional photonic crystal of pillar type.

Similarly to optical fibers silica-based planar waveguides can exhibit the property of photosensitivity when illuminated with UV light. UV-induced changes of refractive index in Ge-doped silica allow for adding new functionality to these components including wavelength filtering with help of Bragg gratings, phase adjustment, wavelength tuning, direct UV-writing of waveguides and birefringence compensation. Bragg gratings imprinted in waveguide core in the same way as done in fibers, allow for building demultiplexers, add-drop filters, dispersion compensators, frequency lockers and other grating assisted devices. In this paper we present the background of the photosensitivity in germanosilica, methods for its improvement as well as technology for fabrication of advanced low dispersion Bragg gratings for 40 Gbps and beyond. We also demonstrate some fabricated wavelength selective devices for WDM communication systems.