Chemically etched ultrahigh-Q wedge-resonator on a silicon chip

Ultrahigh-Q optical resonators are being studied across a wide range of fields, including quantum information, nonlinear optics, cavity optomechanics and telecommunications. Here, we demonstrate a new resonator with a record Q-factor of 875 million for on-chip devices. The fabrication of our device avoids the requirement for a specialized processing step, which in microtoroid resonators8 has made it difficult to control their size and achieve millimetre- and centimetre-scale diameters. Attaining these sizes is important in applications such as microcombs and potentially also in rotation sensing. As an application of size control, stimulated Brillouin lasers incorporating our device are demonstrated. The resonators not only set a new benchmark for the Q-factor on a chip, but also provide, for the first time, full compatibility of this important device class with conventional semiconductor processing. This feature will greatly expand the range of possible ‘system on a chip’ functions enabled by ultrahigh-Q devices

Volume diffraction gratings for optical telecommunications applications: design study for a spectral equalizer

The main characteristics required for a diffraction grating used for demultiplexing functions in spectral equalizing systems are investigated, both theoretically and experimentally. We show that volume-phase holographic (VPH) gratings can be used as dispersive elements instead of classic reflection surface-relief gratings presently employed in most optical telecommunications devices. A design method for this type of diffraction grating and experimental results are presented, confirming that VPH gratings are well suited to such applications

Competitiveness and industrial renewal via production relocation by global multinational networks

Electrical industry is regarded as the backbone of the ICT branch’s hard-ware production. The international settlement of this industry is therefore of paramount interest for developed economies and emerging market economies as well. They all compete for investments in this sector. This study analysis the development of Hungarian electrical industry from the early years of transition when output performance was at the deepest level and when this sector along with the automotive branch became the primary source of eco-nomic expansion. The sector’s performance is compared with data from other CEE countries and with other Hungarian industries in order to illus-trate the widespread modernization effects of foreign investments in this sec-tor. The question of activities ’ relocation from more developed countries to Hungary, and in most recent years from Hungary to less developed regions is also dealt with. Relocations are regarded in this paper from the Hungar-ian viewpoint as necessary and positive developments. Relocated activities give room for other, more sophisticated and more income generating activi-ties

Advances in infrared and imaging fibres for astronomical instrumentation

Optical fibres have already played a huge part in ground based astronomical instrumentation, however, with the revolution in photonics currently taking place new fibre technologies and integrated optical devices are likely to have a profound impact on the way we manipulate light in the future. The Anglo-Australian Observatory, along with partners at the Optical Fibre Technology Centre of the University of Sydney, is investigating some of the developing technologies as part of our Astrophotonics programme. In this paper we discuss the advances that have been made with infrared transmitting fibre, both conventional and microstructured, in particular those based on flouride glasses. Flouride glasses have a particularly wide transparent region from the UV through to around 7um, whereas silica fibres, commonly used in astronomy, only transmit out to about 2um. We discuss the impact of advances in fibre manufacture that have greatly improved the optical, chemical resistance and physical properties of the flouride fibres. We also present some encouraging initial test results for a modern imaging fibre bundle and imaging fibre taper.Comment: 11 pages, 7 figures, to be published in Proc. SPIE 6273 Optomechanical Technologies for Astronom