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We report our advances in development of subwavelength engineered metamaterial structures in silicon waveguides, specifically high-efficiency fiber-chip couplers, ultra-broadband surface grating couplers and nanophotonic beam splitters, evanescent field waveguide sensors and on-chip Fourier-transform spectrometers.
High performance interconnects provide communications for large datacenters. Optical interconnects are replacing copper as bandwidth increases. This paper uses small MEMs optical switches to reconfigure large datacenter interconnects for varying needs.
Broadband green light source using a 5.5-mm-long tandem PPLN was demonstrated. The measured wavelength and temperature bandwidth were 13nm and 100°C, respectively, which had 34.2 times broader spectral bandwidth than periodic one.
We present hermetically encapsulated, mechanically coupled, 20 MHz breathe-mode ring filters with ultra narrow bandwidths of 5.9 kHz and 8.9 kHz, which correspond to 0.029% and 0.044% bandwidth with less than 2.7 dB insertion loss. This is the narrowest percent bandwidth achieved by a mechanically coupled MEMS filter. The ability to attain an insertion loss this small for such a small percent bandwidth...
The demand on portable and user-friendly wireless communication devices has geared up accordingly which necessitates optimal miniaturised built-in antenna for mobile terminals. This paper presents a design of a miniaturized circular microstrip L-probe wideband patch antenna for achieving diversity operation at mobile terminals. The design is optimised to cover the UMTS, LTE and WLAN. A prototype is...
To fully utilize radio resources by intelligently filling in as much radio spectrum gaps as possible, the concept of cognitive radio network has been well accepted. A challenge inherent in this technology is how to build a mechanism that can allocate resource by learning and adapting to a specific radio transmission environment. In this paper, we propose a cognitive resource management scheme that...
A Vivaldi TSA array has been designed and analysed. It can operate over 4-16GHz and be capable of scanning to 50deg. This study shows that the strong mutual coupling between elements plays a constructive role in the array performance of active impedance matching. The introduction of corrugated edge to the TSA element has no effect on the active matching but the scan gains are improved. Further research...
An extremely high power, second harmonic TE21 gyrotron traveling wave amplifier (gyro-TWT) utilizing a MIG beam will be described. Based on a marginal stability procedure [1], a second harmonic gyro-TWT using a 100 kV, 25 A MIG beam with α = 1 and Δvz/vz = 5% has been designed, where the total interaction tube is comprised of three sections separated by absorbing severs. The length of each section...
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