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排序方式: 共有231条查询结果,搜索用时 15 毫秒
1.
Saitoh T. Mattori S. Kinugawa S. Miyagi K. Taniguchi A. Kourogi M. Ohtsu M. 《Lightwave Technology, Journal of》1998,16(5):824-832
We report the modulation characteristics of a waveguide-type optical frequency comb generator (WG-OFCG) with the advantages of compactness, high modulation index and low driving power. The characteristics of the optical frequency comb (OFC) generated when the modulation index exceeds 2π are discussed. The power of the modulation sidebands was measured by the optical heterodyne method with an external-cavity laser as a local oscillator. The dependence of the modulation index of the WG-OFCG on the modulation frequency up to 40 GHz was measured. The generation span of the OFC at the modulation frequency detuned from an integer multiple of the free spectral range (FSR) is discussed 相似文献
2.
Kourogi M. Widiyatomoko B. Takeuchi Y. Ohtsu M. 《Quantum Electronics, IEEE Journal of》1995,31(12):2120-2126
The limit of optical frequency comb (OFC) generation (i.e., the limit of frequency difference measurement) due to the material dispersion in the EO crystal is experimentally studied. By using a modified monolithic OFC generator, we observed the OFC spectrum, and confirmed that the envelope of the OFC around 780 nm extended to a span as wide as 16 nm (or 7.6 THz) reaching the limit of the OFC generation. We also proposed a method of stabilizing the Fabry-Perot cavity for the monolithic OFC generator 相似文献
3.
A quasi-particle (exciton-phonon polariton) model, as a simple model of an optical near-field probe, is proposed to investigate an unresolved problem in photochemical processes, i.e., why a vapor molecule can be dissociated by an incident photon with less energy than the dissociation energy only if, not a propagating far field, but an optical near field is used, and what is the mechanism leading to the photon flux dependence of the deposition rates. Incident photon energy and intensity dependences of Zn deposition rates are analyzed, and good agreement between the theoretical and experimental results is obtained. It suggests that the probe system plays an important role in vibrational transitions as well as electronic transitions in photodissociation processes, and that the couplings between the optical near field and molecular vibrations are enhanced to permit a nonresonant photodissociation inherent in the optical near field. 相似文献
4.
Masayoshi Sugawara Tetsuya Suzuki Atsushi Totsuka Masayasu Takeuchi Kunimasa Ueki 《Starch - St?rke》1994,46(9):335-337
The corn hull dietary fiber was decomposed into their components such as cellulose, hemicellulose-A, -B, -C, -other and lignin by the Siegel method, and their contents were 16%, 1%, 57%, 14% and 2%, respectivity. The components of ordinary corn fiber were insoluble in water, but several decomposed fractions were able to dissolved. The solubility in water of hemicellulose-B was well and of hemicellulose A was slightly, but other fractions were insoluble. Hemicellulose-A, -B, -C and -other fractions were made up of about 30% of arabinose and 50% of xylose. Uronic acid contents and solubility in water of each hemicellulose fraction were mutually related. 相似文献
5.
Masanori Usui Masayasu Ishiko Koji Hotta Satoshi Kuwano Masato Hashimoto 《Microelectronics Reliability》2005,45(9-11):1682
This paper describes the impacts of mechanical stress on vertical power devices. The stress dependence of the DC characteristics of trench insulated gate bipolar transistors (IGBTs) was measured. The experimental results could be reproduced by the device simulation, which included stress dependence models of the carrier mobility and the band gap. We found that the stress dependence of the on-state voltage mainly arose from the MOSFET portion of the IGBT. Using the device simulation, we estimated the effects of mechanical stress on the surge voltage and the saturation current, which give us the important information for designing a power module with higher ruggedness. 相似文献
6.
Ohtsu M. Liou K.-Y. Burrows E.C. Burrus C.A. Eisenstein G. 《Electronics letters》1987,23(21):1111-1113
A problem in frequency-tuning of external-cavity lasers is mode-hopping between neighbouring external-cavity modes. We demonstrate a new interferometric method for monitoring mode-hoping and an automatic control circuit for a 1.3 ?m grating external-cavity laser that maintains single-mode operation when the lasing frequency is tuned. 相似文献
7.
Intensity fluctuations of the longitudinal modes of a 0.8 μm AlGaAs laser were precisely measured during the occurrence of hopping between two modes. It was found from this result that mode hopping follows the stochastics of a Poisson process. The frequency of mode hopping was measured asf_{c} = [exp [-95(I/I_{th} - 1)]] times 10^{7} (Hz). whereI/I_{th} is the injection current normalized to its threshold value. Results of analog computer simulations showed that spontaneous emission worked as a triggering force for mode hopping. Results of the analysis based on the Fokker-Planck equation were compared to the experimental results, from which the root-mean-square value of the fluctuating electric field of spontaneous emission was estimated as2.3 times 10^{2) (V/m)leqlanglesim{E}_{N} leq 3.2 times 10^{2} (V/m). It is concluded that an effective reduction of mode hopping is achieved if the laser is operated at a higher bias or if the coupling constant between the two modes is increased. 相似文献
8.
Hydrogen production by combining two types of photosynthetic bacteria with different characteristics
Toshihiko Kondo Masayasu Arakawa Tatsuki Wakayama Jun Miyake 《International Journal of Hydrogen Energy》2002,27(11-12)
The double-layer photobioreactor using two types of photosynthetic bacteria, Rhodobacter sphaeroides RV and its reduced-pigment mutant, MTP4, was developed for efficient hydrogen production. The two types of bacteria had different characteristics on light energy, hydrogen production rate and conversion efficiency. MTP4 produced hydrogen more efficiently under high light conditions and RV did so under low light conditions. Illuminated light toward the surface of a photobioreactor quasi-exponentially declines as it penetrates into the reactor. When two types of bacteria were placed using the developed reactor according to this light distribution, the hydrogen production rate reached 3.64 l/m2/h at a light intensity of 500 W/m2 in 24 h and the conversion efficiency of light energy to hydrogen was 2.18%. These values were 33% higher than those of only using RV. The low light in the deep part of the reactor was utilized efficiently, resulting in a higher hydrogen production rate. 相似文献
9.
10.
Ohtsu M. Liou K.-Y. Burrows E.C. Burrus C.A. Jr. Eisenstein G. 《Lightwave Technology, Journal of》1989,7(1):68-76
The mode-hopping events in a 1.3-μm grating-tuned external-cavity laser are analyzed on the basis of interferometric measurements. The average frequency of mode hopping for a 7.5-cm external-cavity laser is estimated and is expressed as f c =2.7×106×exp [-1.7/(I /I th-1)] (hertz) for 0.07⩽(I /I th -1)⩽0.8 (I =injection current and I th =threshold current). The mode-hopping monitoring signal was negatively fed back to the laser using an automatic control circuit which maintained single-mode operation while the wavelength of the grating external-cavity laser was tuned 相似文献