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Wireless local area networks based on the IEEE 802.11 standard are rapidly replacing wires within homes and offices. The latest datarate amendment to the IEEE 802.11 standard, known as the 802.11n, provides enhanced user experience by exploiting MIMO techniques that use multiple antennas for both transmitter and receiver. In conjunction with MAC layer improvements such as aggregating data, the 802.11n standard supports PHY data rates as high as 600 Mb/s with four spatial streams. This article discusses various MAC and PHY level modifications introduced in 802.11n, as well as the architecture, design trade-offs, and implementation details of a two spatial stream CMOS 802.11n-draft-compliant SoC. [ABSTRACT FROM AUTHOR]

Two-photon absorption coefficients of GaN for below band gap ultraviolet wavelength and midgap infrared wavelength were measured by using femtosecond pulsewidth autocorrelation and Z-scan techniques. Large two-photon absorption coefficients were obtained. Taking advantage of the large two-photon absorption, we have demonstrated two-photon confocal imaging of a GaN thin film. Direct correlation was found between the yellow luminescence and suppression of bandedge luminescence. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have observed progressive damage due to reabsorption of stimulated emission in optically pumped laser-quality GaInN–GaN multiple quantum wells. The degradation occurred on a time scale consistent with the lifetime of electrically pumped lasers incorporating the same active region, suggesting that the failure mechanism was in part catastrophic optical damage, and not just heating in the p contact and p cladding as is often assumed. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]