31results about How to "High pattern purity" patented technology

The invention discloses a 1 μm band cylindrical vector fiber laser based on a mode selective coupler, including a pump source, a wavelength division multiplexer, a gain fiber, a circulator, a single-mode cloth Bragg grating, a first polarization controller, and a second polarization A controller, a mode selection coupler and a collimator; the output end of the pump source is connected to the short-wavelength input end of the wavelength division multiplexer, and the output end of the wavelength division multiplexer is connected to port 1 of the circulator through a gain fiber, Port 2 of the circulator is connected to a single-mode Bragg grating, port 3 of the circulator is connected to the long wavelength of the first polarization controller, mode selective coupler and wavelength division multiplexer, and the second polarization controller and collimator are connected to the mode Select the few-mode fiber output of the coupler. The invention has the advantages of high slope efficiency of fiber laser, small insertion loss and high polarization purity of column vector laser.

The invention provides a device and a method for generating columnar vector beams in optical fiber by utilizing an electrically-controlled tunable optical grating. By means of the linear polarization characteristic of the electrically-controlled tunable optical grating, efficient coupling between a linear polarization vector basic mode in a fiber core and TM01 and TE01 modes can be realized, and a columnar vector light field with strict radial and angular polarization characteristics can be generated. Complete coupling between the linear polarization vector basic mode and the columnar vector light field can be realized by optimizing the refractive index modulation degree of the electrically-controlled tunable optical grating. Columnar vector light can be generated in different wavelength positions of the optical fiber conveniently by adjusting and modulating the period of the electrically-controlled tunable optical grating. The adopted device is simple and has high columnar vector light field generation efficiency, the generated columnar vector light beams have high mode purity, meanwhile, different radial and angular vector light fields can be conveniently converted, and the columnar vector light field can be generated in different wavelengths by adjusting radio-frequency signals.

A nonlinear holographic generation method and device for propagating an invariant structured light field, belonging to the field of optics, the purpose is to solve the problem of the limited spectral bandwidth of the structured light field generated based on the linear process and the intensity dependence of the structured light field generated based on the nonlinear process sex issue. The method includes: using a holographic modulation method to modulate a Gaussian pump beam into a fundamental-frequency beam having a spatial mode related to the order of frequency doubling; making the fundamental-frequency beam unidirectionally incident into a k-frequency doubling crystal after passing through an imaging unit; The beam emitted from the k-frequency doubling crystal is separated to obtain a frequency up-converted beam with a propagating invariant structured light field. In the device, the modulator modulates the Gaussian pump beam into a fundamental frequency beam having a spatial mode related to the order of frequency doubling; the fundamental frequency beam is unidirectionally incident on the k-frequency doubling crystal after passing through the imaging unit; the separation element pairs The beam emitted from the k-frequency doubling crystal is separated to obtain a frequency up-converted beam with a propagating invariant structured light field.

The invention discloses a broadband confocal waveguide HE0n mode excitation device, which belongs to the technical field of vacuum electronics. The device includes an output open confocal waveguide section, a closed confocal waveguide mode conversion section, a cut-off gradient section, and a uniform open waveguide in the cut-off section; a Y-shaped 3dB power splitter is provided at the junction of the closed confocal waveguide mode conversion section and the cut-off gradient section. The two output waveguides are bent inward at 90 degrees and are perpendicular to the input waveguide, and the output port obtains two microwave signals of equal amplitude and opposite directions. The invention adopts a double-fed structure perpendicular to the confocal waveguide mirror surface, and realizes the high-efficiency conversion of the HE0n mode of the confocal waveguide within a broadband range through two pairs of reflective mirror surfaces in the cut-off transition section, and the band is flat. It can be realized by traditional processing methods in the millimeter wave and terahertz frequency bands; the sensitivity of the structural parameters is low, and it can be directly applied to the input coupling device of the confocal waveguide cyclotron amplifier device, the cyclotron oscillator device and the cyclotron amplifier in the millimeter wave and terahertz frequency bands Cold test experiment of high-frequency system characteristics of components.

The invention discloses a circular waveguide TM 11 The invention discloses a pattern exciter of a pattern, which belongs to the technical field of high-power millimeter wave testing. The mode exciter includes a power division structure, a coupling excitation structure and an output structure. TE 10 After the mode passes through the power division structure, it is divided into two groups of TE with equal amplitude and 180° phase difference. 10 The mode reaches the coupling end. At the coupling end, two sets of rectangular waveguides TE 10 The modes are efficiently coupled into the ridge-gap waveguide by the two coupling probes of the coupled excitation structure, and converted into two sets of quasi-TEM modes of the ridge-gap waveguide with equal amplitude and 180° phase difference, which are respectively transmitted to the two excitation probes by the ridge-gap waveguide. At the needle, a set of equal-amplitude and anti-phase TEM waves are excited at the excitation end of the output structure through the excitation probe. This group of TEM waves becomes a circular waveguide TM after vector synthesis 11 The mode is output to the circular waveguide transmission link through the output port. The mode exciter of the present invention can generate a circular waveguideTM in a broadband 11 Mode, the mode has high purity, small transmission loss, and compact structure, which is conducive to system integration.