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Generalized Two-State Theory for an Atom Laser with Nonlinear Couplings

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Communications in Theoretical Physics 2002年第7期38卷 35-40页

作者： JING Hui TIAN Li-Jun Laboratory for Quantum optics Shanghai Institute of Optics and Fine Mechanics Shanghai 201800 China Theoretical Physics Division Nankai Institute of Mathematics Nankai University Tianjin 300071 China

We present a generalized two-state theory to investigate the quantum dynamics and statistics of an atom laser with nonlinear couplings. The rotating wave approximate Hamiltonian of the system is proved to be analytically solvable. The fraction of output atoms is then showed to exhibit an interesting collapse and revival phenomenon with respect to the evolution time, a sign of nonlinear couplings. Several nonclassical effects, such as sub-Poissonian distribution, quadrature squeezing effects, second-order cross-correlation and accompanied violation of Cauchy-Schwartz inequality are also revealed for the output matter wave. The initial global phase of the trapped condensate, in weak nonlinear coupling limits, is found to exert an interesting impact on the quantum statistical properties of the propagating atom laser beam.

关键词： atom laser, nonlinear couplings, nonclassical effects

Influences of cavity dispersion distribution on the output pulse properties of an all-normal-dispersion fiber laser

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Chinese Physics B 2015年第7期24卷 268-274页

作者：李磐时雷孙青冯素娟毛庆和 Anhui Provincial Key Laboratory of Photonics Devices and Materials Anhui Institute of Optics and Fine MechanicsChinese Academy of Sciences Beijing Aerospace Control Instrument Research Institute optics division National Institute of Metrology

In this paper, the influences of the dispersion distribution in the cavity on the output pulse properties of the all-normaldispersion（ANDi） fiber laser are investigated. Our simulations show that, as the relative length of the dispersion fiber increases, the temporal width and the spectral bandwidth of the output pulse for an ANDi fiber laser with fixed total cavity dispersion or fiber length are decreased, while the pulse energy is enhanced and the compressed pulse width is *** simulation predictions have been proved by our experimental results. The reason may be that the nonlinear phase shift accumulated in the nonlinear fiber is more than that in the dispersion fiber if they have the same length.

关键词： mode-locked lasers fiber lasers dispersion nonlinearity

A Ka-band low-noise amplifier with a coplanar waveguide(CPW)structure with 0.15-μm GaAs pHEMT technology

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Journal of Semiconductors 2010年第1期31卷 69-72页

作者：吴家松张建煌刘兴中林泰勇吴宪明 Department of Electronic Engineering Vanung University Materials & Electro-optics Research division Chung-Shan Institute of Science & Technology

This investigation explores a low-noise amplifier （LNA） with a coplanar waveguide （CPW） structure, in which a two-stage amplifier is associated with a cascade schematic circuit, implemented in 0.15μm GaAs pseudomorphic high electron mobility transistor （pHEMT） technology in a Ka-band （26.540.0 GHz） microwave monolithic integrated circuit （MMIC）. The experimental results demonstrate that the proposed LNA has a peak gain of 12.53 dt3 at 30 GHz and a minimum noise figure of 3.3 dB at 29.5 GHz, when biased at a Vds of 2 V and a Vgs of-0.6 V with a drain current of 16 mA in the circuit. The results show that the millimeter-wave LNA with coplanar waveguide structure has a higher gain and wider bandwidth than a conventional circuit. Finally, the overall LNA characterization exhibits high gain and low noise, indicating that the LNA has a compact circuit and favorable RF characteristics. The strong RF character exhibited by the LNA circuit can be used in millimeter-wave circuit applications.

关键词： LNA Ka-band CPW GaAs pHEMT MMIC

High linearity 5.2-GHz power amplifier MMIC using CPW structure technology with a linearizer circuit

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Journal of Semiconductors 2010年第2期31卷 33-37页

作者：吴家松林泰勇吴宪明 Department of Electronic Engineering Vanung University Materials & Electro-optics Research division Chung-Shan Institute of Science & Technology

A built-in linearizer was applied to improve the linearity in a 5.2-GHz power amplifier microwave monolithic integrated circuit（MMIC）,which was undertaken with 0.15-μm AlGaAs/InGaAs D-mode PHEMT technology. The power amplifier（PA） was studied taking into account the linearizer circuit and the coplanar waveguide（CPW） *** on these technologies,the power amplifier,which has a chip size of 1.44×1.10 mm^2,obtained an output power of 13.3 dBm and a power gain of 14 dB in the saturation *** input third-order intercept point （IIP3） of-3 dBm,an output third-order intercept point（OIP3） of 21.1 dBm and a power added efficiency（PAE） of 22% were attained,***,the overall power characterization exhibited high gain and high linearity,which illustrates that the power amplifier has a compact circuit size and exhibits favorable RF *** power circuit demonstrated high RF characterization and could be used for microwave power circuit applications at 5.2 GHz.

关键词： power amplifier linearizer MMIC CPW

Absolute cryogenic radiometer for high accuracy optical radiant power measurement in a wide spectral range

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Chinese optics Letters 2019年第9期17卷 50-54页

作者： Haiyong Gan Yingwei He Xiangliang Liu Nan Xu Houping Wu Guojin Feng Wende Liu Yandong Lin division of optics National Institute of Metrology

An absolute cryogenic radiometer(ACR) with a detachable optical window was designed and built for high accuracy optical radiant power measurement and photodetector spectral responsivity calibration. The ACR receiver is an electroplated pure copper cavity with a 50-μm-thick wall and inner surface coated with a specular black polymer material mixed with highly dispersible carbon nanotubes. The absorptivity of the cavity receivers was evaluated to be ≥0.9999 in the 250 nm–16 μm wavelength range and ≥0.99995 in 500 nm–16 μm. The cavity receiver works at the temperature of ~5.2 K with nanowatt-level noise-equivalent power. The relative standard uncertainty is 0.041% for the measurement of ~100 μW optical radiant power(250 nm–16 μm) and 0.015% for^1 m W(500 nm–16 μm).

关键词： Absolute cryogenic radiometer optical radiant power measurement

Mid-IR dual-wavelength difference frequency generation in uniform grating PPLN using index dispersion control

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Chinese Physics B 2013年第12期22卷 268-271页

作者：常建华孙青葛益娴王婷婷陶在红张闯 Jiangsu Key Laboratory of Meteorological Observation and Information Processing Nanjing University of Information Science & Technology optics division National Institute of Metrology

A novel widely tunable dual-wavelength mid-IR difference frequency generation （DFG） scheme with uniform grating periodically poled lithium niobate （PPLN） is presented in this paper. By using the temperature-dependent dispersion property of PPLN, the quasi-phase matching （QPM） peak for the pump may evolve into two separate ones and the wavelength spacing between them increases with the decrease of the crystal temperature. Such two pump QPM peaks may allow simultaneous dual-wavelength mid-IR laser radiations while properly setting the two fundamental pump wavelengths. With this scheme, mid-IR dual-wavelength laser radiations at around 3.228 and 3.548, 3.114 and 3.661, and 3.019 and 3.76 μm, are experimentally achieved for the crystal temperatures of 90, 65, and 30 ℃, respectively, based on the fiber laser fundamental lights.

关键词： mid-IR difference frequency generation quasi-phase matching dual-wavelength

Design and fabrication of broadband rugate filter

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Chinese Physics B 2012年第5期21卷 335-339页

作者：张俊超方明邵宇川晋云霞贺洪波 Key Laboratory of Material Science and Technology for High Power Lasers Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences Optic and Laser division National Institute of Metrology

The design and the deposition of a rugate filter for broadband applications are *** bandwidth is extended by increasing the rugate period continuously with *** width and the smoothness of the reflection band with the distribution of the periods are *** improvement of the steepness of the stopband edges and the suppression of the side lobes in the transmission zone are realized by adding two apodized rugate structures with fixed periods at the external broadband rugate filter *** rapidly alternating deposition technology is used to fabricate a rugate filter *** measured transmission spectrum with a reflection bandwidth of approximately 505 nm is close to that of the designed broadband rugate filter except a transmittance peak in the *** on the analysis of the cross-sectional scanning electron microscopic image of the sample,it is found that the transmission peak is most likely to be caused by the instability of the deposition rate.

关键词： rugate filter broadband rapidly alternating deposition

Joint transfer of time and frequency signals and multi-point synchronization via fiber network

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Chinese Physics B 2016年第1期25卷 608-615页

作者：程楠陈炜刘琴徐丹杨飞桂有珍蔡海文 Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques Shanghai Institute of Optics and Fine MechanicsChinese Academy of Sciences Key Laboratory for Quantum optics CAS Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

A system of jointly transferring time signals with a rate of 1 pulse per second （PPS） and frequency signals of 10 MHz via a dense wavelength division multiplex-based （DWDM） fiber is demonstrated in this paper. The noises of the fiber links are suppressed and compensated for by a controlled fiber delay line. A method of calibrating and characterizing time is described. The 1PPS is synchronized by feed-forward calibrating the fiber delays precisely. The system is experimen- tally examined via a 110 km spooled fiber in laboratory. The frequency stabilities of the user end with compensation are 1.8x 10-14 at 1 s and 2.0x 10-17 at 104 s average time. The calculated uncertainty of time synchronization is 13.1 ps, whereas the direct measurement of the uncertainty is 12 ps. Next, the frequency and 1PPS are transferred via a metropoli- tan area optical fiber network from one central site to two remote sites with distances of 14 km and 110 km. The frequency stabilities of 14 km link reach 3.0x 10-14 averaged in 1 s and 1.4x 10-17 in 104 s respectively; and the stabilities of 110 km link are 8.3 x 10-14 and 1.7 x 10-17, respectively. The accuracies of synchronization are estimated to be 12.3 ps for the 14 km link and 13.1 ps for the 110 km link, respectively.

关键词： joint time and frequency transfer optical compensation time synchronization

Wide-angle and broadband graded-refractive-index antireflection coatings

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Chinese Physics B 2013年第4期22卷 253-257页

作者：张俊超熊利民方明贺洪波 Optic and Laser division National Institute of Metrology Key Laboratory of Material Science and Technology for High Power Lasers Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

The design and fabrication of graded-refractive-index （GRIN） antireflection （AR） coatings with wide-angle and broadband characteristics are demonstrated. The optimization of the graded-index profiles with a genetic algorithm is used in the design of the GRIN AR coatings. The average reflectance over a wavelength range from 400 nm to 800 nm and angles of incidence from 0° to 80° could be reduced to only 0.1% by applying an optimized AR coating onto BK7 glass. The optimization of step-graded GRIN AR coating is then further investigated in detail. A two-layer AR coating was deposited by electron beam evaporation with glancing angle deposition technology, and the positional homogeneity was improved by depositing the film from two opposite directions. The microstructure of the AR coating was investigated by scanning electron microscopy, and the residual reflectances of the coating sample are in agreement with theoretical calculations. The optimized GRIN AR coatings are beneficial to increasing the efficiency of light utilization.

关键词： antireflection wide-angle broadband refractive-index profile