A Smart Frequency Presetting Technique for Fast Lock-in LC-PLL Frequency Synthesizer

This paper proposes a smart frequency presetting technique for fast lock-in LC-PLL frequency synthesizer. The technique accurately presets the frequency of VCO with small initial frequency error and greatly reduces the lock-in time. It can automatically compensate preset frequency variation with process and temperature. A 2.4GHz synthesizer with 1MHz reference input was implemented in 0.35 mu m CMOS process. The chip core area is 0.4mm(2). Output frequency of VCO ranges from 2390 to 2600MHz. The measured results show that the typical lock-in time is 3 mu s. The phase noise is -112dBc/Hz at 600KHz offset from center frequency. The test chip consumes current of 22mA that includes the consumption of the I/O buffers.

When is `partial' adequate? A logic-based proof technique using partial specifications

A technique is presented for ascertaining when a (finite-state) partial process specification is adequate, in the sense of being specified enough, for contexts in which it is to be used. The method relies on the automatic generation of a modal formula from the partial specification; if the remainder of the network satisfies this formula, then any process that meets the specification is guaranteed to ensure correct behavior of the overall system. Using the results, the authors develop compositional proof rules for establishing the correctness of networks of parallel processes and illustrate their use with several examples

An automatic step adjustment method for average power analysis technique used in fiber amplifiers

An automatic step adjustment (ASA) method for average power analysis (APA) technique used in fiber amplifiers is proposed in this paper for the first time. In comparison with the traditional APA technique, the proposed method has suggested two unique merits such as a higher order accuracy and an ASA mechanism, so that it can significantly shorten the computing time and improve the solution accuracy. A test example demonstrates that, by comparing to the APA technique, the proposed method increases the computing speed by more than a hundredfold under the same errors. By computing the model equations of erbium-doped fiber amplifiers, the numerical results show that our method can improve the solution accuracy by over two orders of magnitude at the same amplifying section number. The proposed method has the capacity to rapidly and effectively compute the model equations of fiber Raman amplifiers and semiconductor lasers. (c) 2006 Optical Society of America

Prediction of simultaneously large and opposite generalized Goos-Hanchen shifts for TE and TM light beams in an asymmetric double-prism configuration

It is predicted that large and opposite generalized Goos-Hanchen (GGH) shifts may occur simultaneously for TE and TM light beams upon reflection from an asymmetric double-prism configuration when the angle of incidence is below but near the critical angle for total reflection, which may lead to interesting applications in optical devices and integrated optics. Numerical simulations show that the magnitude of the GGH shift can be of the order of beam's width.

Fast calculation technique for scattering in T-matrix method

In scattering calculations using the T-matrix method, the calculation of the T-matrix involves multiplication and inversion of matrices. These two types of matrix operations are time-consuming, especially for the matrices with large size. Petrov et al. [D. Petrov, Y. Shkuratov, G. Videen, Opt. Lett. 32 (2007) 1168] proposed an optimized matrix inversion technique, which suggests the inversion of two matrices, each of which contains half the number of rows. This technique reduces time-consumption significantly. On the basis of this approach, we propose another fast calculation technique for scattering in the T-matrix method, which obtains the scattered fields through carrying out only the operations between matrices and the incident field coefficient. Numerical results show that this technique can decrease time-consumption by more than half that of the optimized matrix inversion technique by Petrov et al. (c) 2008 Elsevier B.V. All rights reserved.

Real-time non-destructive testing of dynamic holograms in doubly-doped LiNbO3 crystals using phase-conjugate technique

Nankai University

DELINEATION OF DEFECTS IN SIMOX STRUCTURES USING A CHEMICAL ETCHING TECHNIQUE

Residual defects in the overlayer of fully annealed SIMOX material have been studied by means of a chemical etching technique. The etching procedure has been calibrated and an optimum recipe is reported. Observations using optical microscopy and transmission electron microscopy have been used to quantify the defect densities and good agreement between the two techniques has been established, confirming that the optimised chemical etching process can be used with confidence to determine the dislocation density for values < 10(7) cm-2.

METASTABLE DEFECT IN AMORPHOUS-SILICON SOLAR-CELLS INVESTIGATED BY JUNCTION RECOVERY TECHNIQUE

The effect of metastable defects caused by light soaking and carrier injection on the transport of carriers in undoped a-Si:H has been investigated by a junction recovery technique. The experiments show that after light soaking or carrier injection the product of mu-p-tau-p decreases, but no detectable change in the distribution of shallow valence band tail states was found.

Lapping technique of InP single crystal wafer

The wafer processing of Indium Phosphide (InP) is so important that it is getting more and more attentions. Lapping is a basic step just following the ingot cutting. In this paper, the influences of various processing parameters on the lapped wafer quality and lapping rate have been checked, the double-crystal X-ray diffraction results about lapped wafers also were presented here. According to the experimental results, the optimum lapping conditions have been obtained.

Quantum coherent networks: A theoretical study

Electron transport in quantum coherent networks (interacting quantum waveguide arrays) is investigated theoretically with use of the scattering-matrix method. The scattering matrix for the basic unit of networks, the cross junction with Square or rounded corners, is derived using the mode-matching technique, The overall scattering matrix for the network is obtained by the composition of the scattering matrices associated with each unit of the network, For a uniform network, the transmission spectra are calculated in the single-mode regime and an found notably dependent on the junction geometry. Small reflection for the input terminal and uniform output for some output ports are obtained, which means that the quantum coherent network can be used as a distributing net for the electron waves. Cross junctions with rounded corners of large radii are found to play a negative role in the device application of quantum coherent networks. (C) 1997 American Institute of Physics.