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Patent
Beijing Information Science and Technical University | Date: 2016-10-13

A fiber grating demodulation system for enhancing spectral resolution by finely adjusting a slit, includes a laser pump source, a wavelength division multiplexer, a fiber Bragg grating, a diaphragm, a slit, a collimating mirror, a light splitting grating, an imaging focus mirror, and a linear array detector. The laser pump source, the wavelength division multiplexer, the fiber Bragg grating are connected in sequence, and the wavelength division multiplexer is connected to the diaphragm. Light emitted from the laser pump source is multiplexed by the wavelength division multiplexer and then enters the fiber Bragg grating, a reflection spectrum of the fiber Bragg grating enters the slit of the fiber grating demodulation system as injected light. After passing through the slit, the injected light is reflected by the collimating mirror, the light splitting grating, and the imaging focus mirror in sequence, and is finally converged to the linear array detector.


Patent
Beijing Information Science and Technical University | Date: 2016-10-13

A fiber grating demodulation system for enhancing spectral resolution of a detector array, includes a laser pump source, a wavelength division multiplexer, a fiber Bragg grating, a diaphragm, a slit, a collimating mirror, a light splitting grating, an imaging focus mirror, and a linear array detector. The laser pump source, the wavelength division multiplexer, and the fiber Bragg grating are connected in sequence, and the wavelength division multiplexer is connected to the diaphragm. Light emitted from the laser pump source is multiplexed by the wavelength division multiplexer and then enters the fiber Bragg grating. A reflection spectrum of the fiber Bragg grating enters the slit of the fiber grating demodulation system as injected light. After passing through the slit, the injected light is reflected by the collimating mirror. The light splitting grating, and the imaging focus mirror in sequence, and is finally converged to the linear array detector.


Patent
Beijing Information Science and Technical University | Date: 2016-10-13

A fiber grating demodulation system for enhancing spectral resolution by finely adjusting an imaging focus mirror, includes a laser pump source, a wavelength division multiplexer, a fiber Bragg grating, a diaphragm, a slit, a collimating mirror, a light splitting grating, an imaging focus mirror, a linear array detector. The laser pump source, the wavelength division multiplexer, the fiber Bragg grating are connected in sequence, the wavelength division multiplexer is connected to the diaphragm. Light emitted from the laser pump source is multiplexed by the wavelength division multiplexer and then enters the fiber Bragg grating, a reflection spectrum of the fiber Bragg grating enters the slit of the fiber grating demodulation system as injected light. After passing through the slit, the injected light is reflected by the collimating mirror, the light splitting grating, and the imaging focus mirror in sequence, and is finally converged to the linear array detector.


Patent
Beijing Information Science and Technical University | Date: 2016-10-13

A fiber grating demodulation system for enhancing spectral resolution by finely adjusting a linear array detector, includes a laser pump source, a wavelength division multiplexer, a fiber Bragg grating, a diaphragm, a slit, a collimating mirror, a light splitting grating, an imaging focus mirror, a linear array detector. The laser pump source, the wavelength division multiplexer, and the fiber Bragg grating are connected in sequence, the wavelength division multiplexer is connected to the diaphragm. Light emitted from the laser pump source is multiplexed by the wavelength division multiplexer and then enters the fiber Bragg grating, and a reflection spectrum of the fiber Bragg grating enters the slit of the fiber grating demodulation system as injected light. After passing through the slit, the injected light is reflected by the collimating mirror, the light splitting grating, the imaging focus mirror in sequence, and is finally converged to the linear array detector.


Patent
Beijing Information Science and Technical University | Date: 2016-10-13

A fiber grating demodulation system for enhancing spectral resolution by finely adjusting a light splitting grating, includes a laser pump source, a wavelength division multiplexer, a fiber Bragg grating, a diaphragm, a slit, a collimating mirror, a light splitting grating, an imaging focus mirror, and a linear array detector. The laser pump source, the wavelength division multiplexer, the fiber Bragg grating are connected in sequence, the wavelength division multiplexer is connected to the diaphragm. Light emitted from the laser pump source is multiplexed by the wavelength division multiplexer and then enters the fiber Bragg grating, a reflection spectrum of the fiber Bragg grating enters the slit of the fiber grating demodulation system as injected light. After passing through the slit, the injected light is reflected by the collimating mirror, the light splitting grating, and the imaging focus mirror in sequence, and is finally converged to the linear array detector.


Zhang L.,Beijing Information Science and Technical University
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2012

EEG Synchronization is considered the conformity of the brain functional areas. Advanced brain function requires many nervous systems with a specific function in relevant brain regions (areas) to achieve integration and coordination at different levels. In this paper, a new method for phase synchronization analysis-Mutually Approximate Entropy is proposed to process different frequency band of EEG signal during audio-visual stimulation and get Similar results with the method of Synchronization Index and Mutual Information Entropy. This showed that the Mutually Approximate Entropy can lead to a good indication of the phase synchronization between two leads. The paper also explored the brain reaction zone by the results of the phase synchronization analysis. The research work lays the foundation for the brain-computer interface design.


Patent
Beijing Information Science and Technical University | Date: 2014-10-08

A gas detection system with an inner ring cavity fiber laser using saturated absorption optical fiber is provided. The system comprising a ring fiber laser consisted of a pump source, a wavelength division multiplexer, a first active optical fiber, a first coupler, a fiber Bragg grating and a second coupler connected successively; an optical isolator coupled between said first active optical fiber and said first coupler; a second active grating connected between said fiber Bragg grating and said first coupler; a detection gas chamber connected between said first coupler and said second coupler; a first photoelectric detector for detecting the laser intensity outputted from said ring fiber laser to generate a first light intensity signal; a second photoelectric detector for receiving the intensity measuring beam passing through the detection gas chamber to generate a second light intensity signal; and a feedback control unit.


Patent
Beijing Information Science and Technical University | Date: 2013-10-09

A method for measuring the strain of material using a short cavity fiber laser, includes steps of: a) arranging the short cavity fiber laser, which laser comprises sequentially coupled laser diode pumping source, a wavelength division multiplexer, a fiber bragg grating, an active fiber and a loop mirror; b) fixing the short cavity fiber laser on the material whose strain will be measured, and matching the stretching direction of the fiber of the short cavity fiber laser with the direction of the strain produced by the material to be measured; c) measuring the drift amount of longitudinal mode output by the short cavity fiber laser; and d) calculating and obtaining the strain of the material to be measured.


Patent
Beijing Institute of Technology, Beijing Information Science and Technical University | Date: 2013-09-02

The present invention provides an angular rate gyro in which a bell-shaped vibrator having nonuniform thickness, axially symmetric and multi curved surface combined structural features is used as a sensitive element. The angular rate gyro is composed of the bell-shaped vibrator, a vibrator fixing shaft, a vibrator base, an airtight hood, a housing and a circuit system. The bell-shaped vibrator includes a bell shoulder having a hemispheric shell structure, a bell waist having a cylindrical shell structure and a bell lip having a hyperboloidal shell structure. The bell-shaped vibrator, the base and a central shaft are mechanically and fixedly connected together to be formed into an integral core having sensitive gyratory effect. A circuit system is used to control vibration forms of the bell-shaped vibrator, perform signal processing and solve the applied angular rate.


Patent
Beijing Information Science and Technical University | Date: 2014-10-01

The present invention provides a fiber laser gas detection system using active feedback compensation by a reference cavity, said system comprising: an optical fiber laser consists of a laser diode pump source, a wavelength division multiplexer, an active optical fiber and a fiber Bragg grating connected successively; an optical isolator coupled with said wavelength division multiplexer for blocking a reverse light transmission in said active fiber; a coupler connected with said optical isolator for dividing the laser light after being isolated by the optical isolator into a reference beam, a detecting beam and an intensity measuring beam according a certain ration power. The gas detection system according to the present invention can take advantages of the unique superiority of compact structure and narrow linewidth of the laser output of the fiber laser, and achieve a gas detection method with high sensitive and high precision by feedback controlling.

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