Using interdisciplinary fields relevant to a highly excited semiconductor — nonequilibrium phenomena in high density plasma, light-induced changes of optical properties, and dynamic holography, we developed time-resolved four-wave mixing technique for monitoring the spatial and temporal carrier dynamics in wide band-gap semiconductors. This opened a new possibility to analyse fast electronic pr...

This theoretical work explores the carrier dynamical issues that must be confronted if the recent successes of the mid-infrared quantum cascade laserss1] are to be translated into longer wavelength devices. Whilst the small subband separations lead to a partial suppression of longitudinal optic (LO) phonon emission, which is the dominant non-radiative loss mechanism in quantum cascade lasers, i...

This paper characterizes the conditions required to form nanoliter-sized droplets (plugs) of viscous aqueous reagents in flows of immiscible carrier fluid within microfluidic channels. For both non-viscous (viscosity of 2.0 mPa s) and viscous (viscosity of 18 mPa s) aqueous solutions, plugs formed reliably in a flow of water-immiscible carrier fluid for Capillary number less than 0.01, although...

In Digital Communication Systems, especially high-speed modems, it is desirable to increase the bit rate while maintaining the same bandwidth without seriously impairing transmission quality. Single-Carrier systems provide a decent bit rate, but Multi-Carrier systems give bit rates that are several orders higher. Asymmetric Digital Subscriber Line (ADSL) services and Orthogonal Frequency Divisi...

We report on measurements of the interstitial iron concentration in boron-doped crystalline silicon by measuring the dissociation rate of iron-boron pairs using a camera-based photoluminescence setup (dynamic Fei imaging). This approach enables us to identify the interstitial iron concentration without measuring absolute values of the carrier lifetime and without knowing the recombination prope...

We propose double-differential (DD) modulation for the amplify-and-forward protocol over Nakagami-m fading channels with carrier offsets. We propose an emulated maximum ratio combining (EMRC) decoder, which could be used by the doubledifferential receiver in the absence of exact channel knowledge. Approximate bit error rate (BER) analysis is performed for the proposed double-differential modula...

The effectiveness of single-epoch integer ambiguity resolution, which provides centimeter-level relative positioning in real-time, is a function of the number, quality and type of carrier phase measurements available. We apply the Local-Minima Search (LMS) method epoch-by-epoch to GPS-GLONASS dual frequency carrier phase measurements taken over 2, 9 and 18 km baselines. While the application of...

I/Q imbalance has been identified as one of the most serious concerns in the practical implementation of the direct conversion receiver architecture. In particular, at the reception of multi-carrier signals the achievable error rate is strictly limited by the I/Q imbalance. Knowledge about the quantitative link between the hardware parameters and the resulting error rate is essential for a reas...

A new wireless communication system denoted as Multi-Code Multi-Carrier CDMA (MC-MC CDMA), which is the combination of Multi-Code CDMA and Multi-Carrier CDMA, is analyzed in this paper. This system can satisfy multi-rate services using multi-code schemes and muti-carrier services used for high rate transmission. The system is evaluated using Traveling Wave Tube Amplifier (TWTA). This type of am...

The feasibility of a multi-carrier system for data-transmission over copper wires at gigabit rates is analyzed. More specific, we look at the effects of jitter and duty-cycle deviations on the SNR and error rate using Matlab simulations. Jitter causes crosstalk between the inphase and quadrature channels of a given tone frequency. Given a certain rms jitter variance, low frequency tones can car...