Cataloged from PDF version of article.InGaN/GaN light-emitting diodes (LEDs) with graded-thickness quantum barriers (GTQB) are designed and grown by metal-organic chemical-vapor deposition. The proposed GTQB structure, in which the barrier thickness decreases from the n-GaN to p-GaN side, was found to lead to an improved uniformity in the hole distribution and thus, radiative recombination rates across the active region. Consequently, the efficiency droop was reduced to 28.4% at a current density of 70 A/cm2, which is much smaller than that of the conventional equal-thickness quantum barriers (ETQB) LED, which is 48.3%. Moreover, the light output power was enhanced from 770 mW for the ETQB LEDs to 870 mW for the GTQB LEDs at 70 A/cm2. © 2013 AIP Publishing LLC

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Monopoles of 1-mm axial length are designed and fabricated on silicon substrates of high-resistivity 5 k⍀-cm and low-resistivity 10 ⍀-cm, respectively. We measure their performance up to 110 GHz for wireless interconnects for the first time. The reflection measurements show that a sharp resonance can be seen at 75 GHz for the meander monopole and monopole pairs at 67 and 104 GHz for the zigzag 30°m onopole on the silicon substrate of high resistivity, but no such sharp resonance can be seen for those on the silicon substrate of low resistivity. Transmission measurements show that a high-gain window exists. The existence of the high-gain window is the most important finding of this work and is useful in the design of chip-scale radios or wireless chip area networks. This suggests that the operating frequency of wireless interconnects be allocated within the high-gain window for good performance. Furthermore, metal lines running parallel with or vertical to the monopole pairs are observed to improve the highest gain of this window area. ABSTRACT: A photonic microwave filter based on fiber loop and fiberBragg gratings (FBGs) is applied in a radio-over-fiber (RoF) system to suppress the relative intensity noise (RIN) of laser and the amplified spontaneous emission (ASE) noise of erbium-doped fiber amplified (EDFA). The experiment results show that the signal-to-noise ratio (SNR) of the system can be effectively improved by using such a noise filter in the system.

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