We studied the phase locking and spectral linewidth of a 2.7 THz quantum cascade laser by mixing its two lateral lasing modes using a superconducting bolometer mixer.
We studied the phase locking and spectral linewidth of a 2.7 THz quantum cascade laser by mixing its two lateral lasing modes using a superconducting bolometer mixer.
The electronic temperatures of individual subbands, the lattice temperature and the population inversion both below and above the laser threshold of THz quantum cascade lasers are extracted by the analysis of interba...
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This article describes two demonstrations at the NTT Group Communication EXPO held at the Tokyo International Forum in December 2005. These showed visitors two of our trials on the feasibility of remotely operating in...
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This article describes two demonstrations at the NTT Group Communication EXPO held at the Tokyo International Forum in December 2005. These showed visitors two of our trials on the feasibility of remotely operating instruments in Chile from Japan: an optical telescope and rock hammers in an underground copper mine. These applications use a relatively high bandwidth of around 100 Mbit/s and require short delay times for smooth interactive operation. To satisfy these requirements we used NTT's experimental research network GEMnet2 in collaboration with partner R&E (research and education) networks in North and South America. The demonstrations showed that Internet-based networks can handle interactive network applications with sufficient quality between two sites separated by almost the maximum possible distance on the Earth as long as the bandwidth and the route are carefully managed.
We demonstrate that photoluminescence from single quantum well structures grown on indium gallium arsenide (InGaAs) compositionally graded buffers on gallium arsenide substrates can be substantially improved by using ...
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Content Addressable Memory (CAM) technology delivers highly scaleable and high performance solutions for evolving network applications like packet classification and flow identification. This paper proposes an innovat...
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Content Addressable Memory (CAM) technology delivers highly scaleable and high performance solutions for evolving network applications like packet classification and flow identification. This paper proposes an innovative CAM/RAM based buffer manager for managing packet buffering and releasing procedures in the data buffer for next generation IP routers. Presently, most of the IP routers use fixed-length memory blocks for buffering packets. If a packet is larger than the size of a memory block, the buffer manager is responsible for chaining together the memory blocks allocated to the packet. This paper uses an integrated CAM/RAM architecture to implement the buffer management operations of the buffer manager by hardware. The functions of conventional soft-maintained free buffer list and its associated pop and return operations can be replaced by hardware CAM/RAM operations. In addition, the proposed buffer manager adopts a novel buffer allocation scheme that can allocate incoming packets with different-size memory blocks, so the wasted buffer area and the number of pointers for chaining together the packet in the data buffer are minimized. The proposed CAM/RAM architecture also supports the multicast management in an elaborate manner. The flexibility of the CAM allows the data buffer to be configured according to the packet size distribution observed from the underlying network thus increasing the efficiency of the memory utilization. This paper extends the applications of CAM/RAM architecture to future high-speed packet switching.
Strain is used in mainstream CMOS production to enhance device performance at the 90 nm node. Strained Si and novel material implementations in fully depleted silicon-on-insulator and multi-gate configurations are of ...
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Strain is used in mainstream CMOS production to enhance device performance at the 90 nm node. Strained Si and novel material implementations in fully depleted silicon-on-insulator and multi-gate configurations are of interest for sub-45-nm applications where there is a need to improve electron and hole mobilities while also providing the electrostatic control necessary for continued geometric device scaling. Implementations of strained Si and strained heterostructures on insulator are reviewed. The Ge-free strained silicon directly on insulator structure has good thermal stability, high electron mobility and improved hole mobilities in particular at low vertical effective electrical fields. In addition, such wafers can readily be incorporated in existing fully or partially depleted silicon on insulator processes. Strained Si/strained SiGe/strained Si heterostructures on insulator provide higher hole mobilities. Simultaneous electron and hole mobility enhancements of 2X at all effective fields are demonstrated in fully-depleted heterostructure on insulator MOSFETs. Thermal budget constraints for processing such devices, particularly with respect to Ge diffusion, are discussed.
We report Raman scattering and photoluminescence (PL) measurements of Ge nanowires (NWs) grown by chemical vapor deposition on silicon substrates with (100) and (111) crystallographic orientations. A sharp and narrow ...
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We report Raman scattering and photoluminescence (PL) measurements of Ge nanowires (NWs) grown by chemical vapor deposition on silicon substrates with (100) and (111) crystallographic orientations. A sharp and narrow Raman peak at ∼ 300 cm-1 indicates single-crystal quality of Ge NWs ∼40 nm in diameter and approximately a micrometer in length. The absence of Si-Ge vibrations in Raman spectra shows that SiGe interdiffusion is insignificant for most of the NW volume. Low temperature PL spectra and the PL intensity-temperature dependence strongly indicate that the observed emission originates mostly at Ge NW Si substrate interfaces, where Si-Ge intermixing has been detected. We found that such interfaces are formed differently for (111) and (100) oriented Si substrates due to the strongly oriented preferential growth direction of Ge NWs.
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