Zhang Chunxi

SiO2 Waveguide Resonator Used in an Integrated Optical Gyroscope

An integrated optical waveguide resonator based on a SiO2 waveguide is proposed, fabricated and tested. The method of designing the resonator is also presented. The optimal splitting ratio of the coupler is gained by simulating the relationship between the splitting ratio of the key coupler in the resonator and the resonators finesse with resonance depth. The calculated fundamental detection limit of this integrated optical waveguide resonator is l.6°/h. Finally, a micro-optical gyroscope system based on the integrated waveguide resonator is built, and the measured resonators finesse F is close to 70 under fluctuating temperature. To the best of our knowledge, the present F is the best result to date. For the coupler splitting rate the experimental results have fixed errors with the simulation results caused by fabrication processes which can be easily eliminated, implying that the method of design is effective and applicable.

Frequency Modulation Induced by using the Linear Phase Modulation Method used in a Resonator Micro-optic Gyro

Resonator micro-optic gyro (R-MOG) sensing rotation angular-velocity is based on Sagnac effect. We present a frequency modulation (FM) induced by the analog triangle-waveform phase modulation (ATAW-PM) technique in an R-MOG. Compared with the traditional serrodyne phase modulation or digital phase modulation methods, the proposed modulation technique has the intrinsic advantage in free of sweeping-back or step-effect induced pulse noise. The influence on dynamic range and resolution of the R-MOG by the parameters of analog triangle-waveform is theoretically analyzed. Experiments are carried out on an R-MOG composed of an integrated optic resonator with a free spectral range (FSR) and a fitness (F) of 1.6 GHz and 61, respectively. Dynamic range of ±500 deg/s and bias drift of 0.6 deg/s over 1 h and 0.05 deg/s for 60s are reliably obtained.

Agreement coordination for second-order multi-agent systems with disturbances

This paper is devoted to the study of consensus problems for the second-order multi-agent systems with external disturbances, switching topology and communication time-delay. Firstly, we perform a model transformation and separate the agreement states from the disagreement states. Secondly, according to this system, we derive a sufficient condition for consensus problem without disturbances by using the Lyapunov-based approach. Furthermore, we give a design criterion in terms of bilinear matrix inequality for the control protocol in the presence of disturbances. Finally, numerical simulations are provided to show the effectiveness of our strategies.

Reduction of nonreciprocal errors in a differential interferometric fiber optical gyroscope using optically differential processing

The bias stability of differential interferometric fiber optical gyroscope is analyzed. Thermal error causing long-term bias drift are reduced by putting the 90° splice in the middle of the fiber coil and applying a wide spectrum light source. Also, a kind of novel optical differential processing, which is much more precise than the electronic differential processing, is proposed for reducing the residual nonreciprocal error in the final differential output. An experimental setup based on optical differential processing was built. An ∼100 fold reduction in the long-term bias drift is demonstrated experimentally compared with the primary differential interferometric fiber optical gyroscope.

Optical Noise Analysis in Dual-Resonator Structural Micro-Optic Gyro

A novel micro resonator optic gyroscope comprising a dual-resonator structure is proposed. This design radically eliminates the noise induced by Rayleigh backscattering, the Kerr effect and polarization coupling. The configuration of the micro optic gyroscope (MOG) is given and described. Three methods are applied to suppress the optical noises in the system and to theoretically analyze the performance improvement. Experiments are carried out on both dual-resonator and single-resonator MOGs, which show the resonance depth improvement from 0.7477 to 0.9173 in the present MOG dual-resonator configuration.

Practice on cultivating computer application ability for the Opto-electronics Engineering students in graduation design

Economic progress and information technology development have spurred the demand of multi-talents. So cultivating the compound talents with computer application ability is one of the main duties for the Subject Construction of Opto-electronics Engineering. According to this, the hierarchical curriculum system of the computer application education for opto-electronics engineering undergraduates is briefly introduced. The problem of how to strengthen training of integrated capability especially the computer application skills of students through graduation design is expatiated emphatically. Taking an example of the graduation design based on LabVIEW, which is such an icon-based graphical programming language that allows engineers to express their ideas in a more intuitive and natural way, the following means are explained: enhancing the capability of problem analysis in starting phase; training of solving problem independently in execution phase; cultivating the ability of induction and summarization in the thesis writing period. The practices show that the above strategies can help students to improve multi-aspect capability and to meet the requirements of society better.

Space radiation effect on fibre optical gyroscope control circuit and compensation algorithm

The process of a γ-irradiation experiment of fibre optical gyroscope (FOG) control circuit was described, in which it is demonstrated that the FOG control circuit, except for D/A converter, could endure the dose of 10krad with the protection of cabin material. The distortion and drift in D/A converter due to radiation, which affect the performance of FOG seriously, was indicated based on the elemental analysis. Finally, a compensation network based on adaptive neuro-fuzzy inference system is proposed and its function is verified by simulation.

Study on variable capacitance diode of (p)nc-Si : H/(n)c-Si heterojunction

Hydrogenated nanocrystalline silicon (nc-Si:H) layers of boron-doped increasing step by step was deposited on n-type crystalline silicon substrate using Plasma Enhanced Chemical Vapor Deposition (PECVD) system. After evaporating Ohm contact electrode on the side of substrate and on the side of nc-Si:H film, a structure of electrode/ (p)nc-Si:H/(n)c-Si/electrode was obtained. It is confirmed by electrical measurement such as I-V curve, C-V curve and DLTS that this is a variable capacitance diode

p+−n−−n+-type power diode with crystalline/nanocrystalline Si mosaic electrodes*

Using p+-type crystalline Si with n+-type nanocrystalline Si (nc-Si) and n+-type crystalline Si with p+-type nc-Si mosaic structures as electrodes, a type of power diode was prepared with epitaxial technique and plasma-enhanced chemical vapor deposition (PECVD) method. Firstly, the basic p+−n−−n+-type Si diode was fabricated by epitaxially growing p+- and n+-type layers on two sides of a lightly doped n−-type Si wafer respectively. Secondly, heavily phosphorus-doped Si film was deposited with PECVD on the lithography mask etched p+-type Si side of the basic device to form a component with mosaic anode. Thirdly, heavily boron-doped Si film was deposited on the etched n+-type Si side of the second device to form a diode with mosaic anode and mosaic cathode. The images of high resolution transmission electronic microscope and patterns of X-ray diffraction reveal nanocrystallization in the phosphorus- and boron-deposited films. Electrical measurements such as capacitance–voltage relation, current-voltage feature and reverse recovery waveform were carried out to clarify the performance of prepared devices. The important roles of (n−)Si/(p+)nc-Si and (n−)Si/(n+)nc-Si junctions in the static and dynamic conduction processes in operating diodes were investigated. The performance of mosaic devices was compared to that of a basic one.

Modeling and performance evaluation of IEEE-1394b isochronous data transfer with DSPN

IEEE-1394b is a high speed data bus, which is widely adopted in various commercial products. Its isochronous data transfer is well suited for time critical data transfer, such as video and audio. However, rare work has been done for IEEE-1394b isochronous data transfer performance evaluation. This paper aims at giving an efficient way for IEEE-1394b isochronous data transfer performance evaluation. First, it gives an overview of IEEE-1394b isochronous data transfer, its bandwidth reservation mechanism and bus owner/supervisor/selector (BOSS) arbitration. Then, a detailed single node model of IEEE-1394b isochronous data transfer with deterministic and stochastic Petri net (DSPN) is proposed, which captures all relevant system aspects in a concise way. The proposed model was evaluated by simulation with TimeNet 4.0. The influences of several system parameters are illustrated. And the upper bound of bus utilization and packet arrival rate of single node bus are also obtained.