A new design of a linear local-feedback MOS transconductor for low frequency applications

For medical devices, low frequency and low power applications are required, and a transconductor which has a low transconductance is needed. A conventional current division scheme for the low transconductance wastes operating current. This paper proposes an improved local-feedback MOS transconductor operating in subthreshold region. The proposed transconductor is optimally designed using maximally flat approximation method, Newton-Raphson method, and Downhill simplex method. From the optimization, two optimum values are obtained. Characteristics of the proposed transconductor are confirmed by simulation. Transfer characteristics of the proposed transconductor are linear, and the power consumption of the proposed transconductor is 1/60 as compared with the presented transconductor using current division scheme. The CMRR is around 70 dB, and the THD is lower than ?55 dB under a condition of that the frequency of the sinusoidal input is 100 Hz. As a demonstration of an application, the proposed transconductor is applied to a low frequency second order Butterworth filter. A cutoff frequency of the filter is 100 Hz. Simulation results show validities and availability of the proposed transconductor.     

Access and metro networks based on WDM technologies

This paper describes the technical issues of access and metro networks based on wavelength division multiplexing (WDM) technologies, some solutions, and an experimental demonstration. A WDM star access network with colorless optical network units (ONUs) is proposed. For realizing the colorless ONU, two approaches are introduced; optical carrier supply and spectrum slicing. In addition, a WDM metro ring network with scalable optical add/drop multiplexers (OADMs), namely the tapped-type OADM, is proposed to effectively accommodate the large amount of traffic issued from access networks. Prototypes are constructed and used to verify the feasibility of the proposed WDM technologies.     

100 Å-thick tunnel junction by double impurity doping liquid phase epitaxy for V-band TUNNETT oscillation

The tunnel injection transit time (TUNNETT) diodes with p⁺p⁺n⁺n⁻n⁺ structure were fabricated by liquid phase epitaxy (LPE). About 100 Å tunnel junction (p⁺n⁺) was successfully prepared by the double impurity diffusion of Ge and S during LPE growth. Continuous wave (CW) oscillation was realized at 51.520 GHz in the V-band cavity with the phase noise of −60 dBc/Hz at 1 kHz bandwidth.     

Proposal for st-Routing Protocol

A routing protocol chooses one of the several paths (routes) from a source node to a destination node in the computer network, to send a packet of information. In this paper, we propose a new routing protocol, which we call st-routing protocol, based on st-numbering of a graph. The protocol fits well in noisy environments where robustness of routing using alternative paths is a major issue. The proposed routing protocol provides a systematic way to retry alternative paths without generating any duplicate packets. The protocol works for only those networks that can be represented by biconnected graphs.     

A MIMO turbo equalizer for frequency-selective channels with unknown interference

A new space-time turbo equalization algorithm is derived for frequency-selective multiple-input-multiple-output (MIMO) channels with unknown interference. The algorithm is an extension of our proposed MIMO equalization algorithm , which performs joint channel estimation, multiple users' signal detection, and decoding, all in an iterative manner. This paper's proposed algorithm uses estimates of the correlation matrix of composite unknown interference-plus-noise components to suppress the unknown interference while effectively separating multiple users' signals to be detected (referred to as "known user" later). The correlation matrix of the composite unknown interference-plus-noise components can be estimated by time averaging the instantaneous empirical correlation matrix over the training period. Since the iterative channel estimation yields better channel estimates as more iterations are performed, thereby the estimate of the correlation matrix of the unknown interference-plus-noise components also becomes more accurate. This results in better signal detection performances, even in the presence of unknown interferers. A series of computer simulations show that this paper's proposed algorithm can properly separate known users' signals while suppressing unknown interference.     

3D Micromolding of Arrayed Waveguide Gratings on Upconversion Luminescent Layers for Flexible Transparent Displays without Mirrors,Electrodes, and Electric Circuits

A new technique for the fabrication of arrayed waveguide gratings on upconversion luminescent layers for flexible transparent displays is reported. Ho³⁺‐ and Yb³⁺‐codoped NaYF₄ nanoparticles are synthesized by hydrothermal techniques. Transparent films consisting of two transparent polymers on the NaYF₄ nanoparticle films exhibit mechanical flexibility and high transparence in visible region. Patterned NaYF₄ nanoparticle films are fabricated by calcination‐free micromolding in capillaries. Arrayed waveguide gratings consisting of the two transparent polymers are formed on the patterned NaYF₄ nanoparticle films by micromolding in capillaries. Green and red luminescence is observed from the upconversion luminescent layers of the NaYF₄ nanoparticle films in the arrayed waveguide gratings under excitation at 980 nm laser light. Arrayed waveguide gratings on the upconversion luminescent layers are fabricated with Er³⁺‐doped NaYF₄ nanoparticles which can convert two photons at 850 and 1500 nm into single photon at 550 nm. These results demonstrate that flexible transparent displays can be fabricated by constructing arrayed waveguide gratings on upconversion luminescent layers, which can operate in nonprojection mode without mirrors, transparent electrodes, and electric circuits.     

Criteria for versatile GaN MOVPE tool:high growth rate GaN by atmospheric pressure growth

Growth rate has a direct impact on the productivity of nitride LED production.Atmospheric pressure growth of GaN with a growth rate as high as 10μm/h and also Al_0.1Ga_0.9N growth of 1μm/h by using 4 inch by 11 production scale MOVPE are described.XRD of（002） and（102） direction was 200 arcsec and 250 arcsec, respectively.Impact of the growth rate on productivity is discussed.     

EXOS-D (AKEBONO) very low frequency plasma wave instruments (VLF)

The Akebono (EXOS-D) satellite has been successfully observing the Earth's magnetosphere since it was launched on February 21, 1989. The objectives of VLF instruments on board the satellite were to investigate the behavior of plasma waves associated with accelerated auroral particles, wave-particle interaction mechanisms, and propagation characteristics of whistler-mode waves in the magnetosphere. The instruments measured not only the dynamic spectra of VLF waves up to 15 kHz by a wideband receiver, but also their absolute field intensities, wave normal vectors, and Poynting vectors. Two electric and three magnetic components with a bandwidth of about 50 Hz up to 12.5 kHz are sent to measure the wave normal vectors and Poynting vectors. The antenna impedance is measured to determine the correct absolute electric field intensities. The instruments have successfully measured the wave spectra, the wave normal vectors. Poynting vectors, the precise wave intensities, the antenna impedance, etc. The present paper describes the unique features of the instruments, especially the Poynting flux analyzers in more detail. Obtained scientific results are also reviewed