This paper presents an insight into the performance degradation in Gilbert mixer due to the voltage stress-induced hot carrier effects. Analytical analysis relates the performance degradation with the model parameter shifts caused by voltage stress. The stress-induced parameter shifts are examined experimentally. Performance degradation in mixer is investigated through Spectre-RF simulation with the models extracted from measured data.

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A simple pass transistor approach using K map is proposed in this communication for design of combinational circuits. The approach is based on switching theory and requires mapping of logic functions into circuit realization using new pass transistor logic style. Low power and small area full adder cell is synthesized which utilized 14 transistors in CMOS implementation.

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Investigation of the surface state of plasma-induced fluorine damage in pseudomorphic high electron mobility transistors (P-HEMTs) using x-ray photoemission spectroscopy (XPS) revealed that the 1s core-level spectrum of fluorine faded out after lengthy x-ray exposure. The x-ray emission apparently caused fluorine desorption from the plasma-damaged P-HEMTs. We thus investigated whether x-ray emission enables P-HEMTs to recover from plasma-induced fluorine damage. The carrier density and electron mobility of P-HEMTs without thermal annealing improved by 63 and 34% with x-ray exposure, while P-HEMTs with thermal annealing improved by 18 and 17%. A secondary ion mass spectrometry (SIMS) profile of fluorine in P-HEMTs with x-ray exposure without thermal annealing showed a reduction in the amount of fluorine in the δ-doped layer and the channel layer, while the profile in P-HEMTs with thermal annealing showed fluorine reduction only below 40nm. Thus, x-ray photoemission is effective in enabling non-thermally annealed P-HEMTs to recover from plasma-induced fluorine damage but not for thermally annealed P-HEMTs.

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This paper evaluates the performance of IP traffic over WDM ring network in the presence of linear crosstalk due to optical add drop multiplexer and nonlinear crosstalk due to four wave mixing. Packet error rate analysis is chosen because it indicates how many IP packets are transmitted in error. The results show that a higher PER occurs in a WDM ring network when the number of nodes, the number of channels and the bit rate are higher. Increasing the burstiness of IP traffic improves the PER performance and allow more channels and larger number of nodes to be accommodated.

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We propose a new pumping method for optical fiber amplifiers at 1480nm and 980nm that is able to provide high gain and low noise-figure. The gain and noise figure obtained were 38.3dB and 5.5dB with an improvement of 3.8dB and 1.4dB, respectively, at 1550nm, for -30dBm input power when compared to its counter-pumped design. This design also delivers higher gain and lower noise figure when compared to the common bi-directional dual-pumped designs. A power conversion efficiency of 44.5% was achieved in this design.

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An improved class of microstrip dual-mode bandpass filter is proposed using the meander-shaped stepped-impedance ring resonator (SIRR). This meander SIRR, together with a uniform impedance ring resonator (UIRR), is at first studied to demonstrate its attractive features of harmonic-resonance suppression and overall-size miniaturization. A pair of squared notches is then etched out on the corners along either of diagonal lines of this symmetrical SIRR that is capacitively driven by the two perpendicular feed lines. Two SIRR-based dual-mode filters are therefore designed, simulated and fabricated. The overall size of this filter finds to be reduced by about 50% in area. The 1^st harmonic passband of this filter is raised to 5.30GHz that exceeds the three times of its fundamental passband at 1.52GHz as verified by experiment.

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Equivalent material parameters of a periodic waveguide structure loaded with double strips printed on dielectric has been extracted. It shows a passband where the relative permittivity and permeability are simultaneously negative also called as double negative (DNG) passband. Full-wave Hybrid MoM-Immittance Approach is employed for the material parameter extraction validated by independent Ansoft High Frequency Structure Simulator (HFSS) extracted results.

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The incorporation of an active single-quantum well in the tuning layer of a DBR laser is proposed as a way of compensating for optical loss and achieving stable single-mode operation during wavelength tuning. Experimental results demonstrate that the structure achieves these goals while maintaining the efficiency of tuning. In application to a short-cavity DBR laser with a gain region 35-µm long, continuous wavelength gtuning over a broad 4.8nm is achieved with stable lasing properties (more than 40dB of side-mode suppression). Fast wavelength switching less than 10ns to cross a wavelength spacing of 2nm is also confirmed.

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