0.98- mu m strained quantum well lasers for coupling high optical power into single-mode fiber

An investigation of epitaxial-layer structures has yielded narrow ridge waveguide structure lasers capable of coupling high optical power into single-mode fiber (SMF). An optical power of well over 60 mW in SMF was obtained for a 2- mu m-wide ridge waveguide laser with a guided separate-confinement-heterostructure (SCH) epitaxial structure. Calculated results indicate that the stringent limit imposed on 0.98- mu m wavelength detuning is relaxed for such high optical power coupled into a SMF. The 0.98- mu m strained-quantum-well lasers thus show considerable promise as a practical low-noise pumping source for Er-doped optical-fiber amplifiers.<>     

Strained InGaAs quantum well lasers with small-divergence anglesfor high-power pump modules

Epitaxial structures were designed for high-power strained InGaAs/AlGaAs quantum well lasers with low vertical-divergence emitting angles. The vertical divergence angles achieved were down to ~20°. High power output 1.02 μm pump modules with well-designed strained quantum well lasers have been developed for a 1.3 μm band Pr⁺ -doped fibre amplifier. A maximum optical fibre output of 157 mW was obtained     

Construction of an indoor radio environment map using gradient boosting decision tree

Wireless Networks - Radio environment maps represent a signal strength map or a coverage area of radio networks. Constructing such maps involves gathering signal coverage information in sparse...     

High-Speed CMOS Track/Hold Circuit Design

This paper describes the design of a high-speed CMOSTrack/Hold circuit in front of an ADC. The Track/Hold circuit employsdifferential open-loop architecture, very linear source follower inputbuffers, NMOS sampling switches and bootstrap sampling-switch drivercircuits for high-speed operation with 3.3 V supply voltage. SPICEsimulations with MOSIS 0.35 m CMOS BSIM3v3 parameters showed thatit achieves a signal-to-(noise+distortion)-ratio (SNDR) of morethan 50 dB for up to 100 MHz sinusoidal input at 200 MS/s with 40 mWpower consumption.     

Kinetic Instability of Boron Heterofullerenes

Although boron heterofullerenes are produced abundantly in the gas phase, they cannot be isolated in macroscopic amounts. Those with two to six boron atoms were found to have minimum bond resonance energies (min BRE) of less than -0.100 |β|. All carbon-boron bonds have negative BREs, suggesting that boron atoms markedly destabilize nearby π bonds. on this theoretical basis, typical boron heterofullerenes are predicted to be kinetically very unstable and chemically very reactive. In contrast, the molecular anions with 60 π electrons of boron heterofullerenes are predicted to be kinetically much more stable. These anions do not have bonds wirh large negative BREs. Some of them may be isolable as salts or endohedral complexes. This study constitutes the first attempt to apply the BRE method to heteroconjugated systems.     

High-power highly reliable 1.06 /spl mu/m InGaAs strained-quantum-well laser diodes by low-temperature growth of InGaAs well layers [MOVPE]

High output power of about 800 mW in a chip and stable operation for over 14 000 h under 225 mW at 50/spl deg/C have been achieved in 1.06 /spl mu/m InGaAs strained-quantum-well laser diodes, which were realised by low-temperature growth of the InGaAs well layers.     

Very High Speed Static Induction Thyristor

Characteristics of a newly developed static induction thyristor (SIThy) are described. The SIThy is irradiated by 2-MeV protons to improve the switching speed as a result of local carrier lifetime control. The characteristics of the proton irradiated SIThy are controlled by annealing conditions to obtain devices for various applications. The switching speed of the SIThy is very high; for example, at an anode current of 50 A, its rise time, storage time, and fall time are 100 ns, 60 ns, and 50 ns, respectively. Thus the newly developed SIThy is suitable for high-speed switching devices.     

Involvement of the retinoid X receptor in the development of imposex caused by organotins in gastropods

Organotin compounds released from antifouling paints, such as tributyltin (TBT) and triphenyltin (TPT), are potent inducers of imposex (a superimposition of male genital tracts, such as penis and vas deferens, on females) in marine gastropods. Little is known about the induction mechanism of gastropod imposex. Here, we show that organotins bind the human retinoid X receptors (hRXRs) with high affinity and that injection of 9-cis retinoic acid (RA), the natural ligand of hRXRs, into females of the rock shell (Thais clavigera) induces the development of imposex. Cloning of the RXR homologue from T. clavigera revealed that the ligand-binding domain of rock shell RXR was very similar to vertebrate RXR and bound to both 9-cis RA and to organotins. These suggest that RXR plays an important role in inducing the development of imposex, namely, the differentiation and growth of male genital tracts in female gastropods.