Abstract: A preparation method of a polymer-derived high-temperature ceramic thin film sensor is provided. Specifically, a sensitive layer precursor layer is prepared by spraying a sensitive layer precursor liquid on an alumina substrate, and the sensitive layer precursor liquid is obtained by mixing precursor liquid with conductive powder. A protective layer precursor liquid is prepared by spraying protective layer precursor liquid on the sensitive layer precursor layer, and the protective layer precursor liquid is obtained by mixing TiB2 nano-powder, insulating powder and the precursor liquid. The protective layer precursor layer, a solder and the sensitive layer precursor layer are simultaneously pyrolyzed by a one-time pyrolysis process, and thus a protective layer, the solder joints and the sensitive layer are obtained simultaneously. Thus, there is no need to pyrolyze the sensitive layer first, saving the time for pyrolyzing the sensitive layer.

Abstract: A preparation method of a polymer-derived high-temperature ceramic thin film sensor is provided. Specifically, a sensitive layer precursor layer is prepared by spraying a sensitive layer precursor liquid on an alumina substrate, and the sensitive layer precursor liquid is obtained by mixing precursor liquid with conductive powder. A protective layer precursor liquid is prepared by spraying protective layer precursor liquid on the sensitive layer precursor layer, and the protective layer precursor liquid is obtained by mixing TiB2 nano-powder, insulating powder and the precursor liquid. The protective layer precursor layer, a solder and the sensitive layer precursor layer are simultaneously pyrolyzed by a one-time pyrolysis process, and thus a protective layer, the solder joints and the sensitive layer are obtained simultaneously. Thus, there is no need to pyrolyze the sensitive layer first, saving the time for pyrolyzing the sensitive layer.

Abstract: A synthesized grating is provided comprising a substrate/layer, and a plurality of alternating aperiodic non-uniform low and high index profiles on a surface of the substrate/layer defining a transmission/reflection spectrum for one of either single or multi-frequency operation of said grating in an optical cavity. A method is also provided for designing the synthesized grating, comprising determining a grating structure of given profiles through analysis of an optimized weighted sum and mapping the grating profile to said surface with the plurality of alternating non-uniform low and high index profiles.

Abstract: A volume liquid fixed-ratio multi-batch mixing valve includes a valve body, including a first inlet liquid chamber, a second inlet liquid chamber and a mixing chamber; a first valve core, controlling liquid inflow into the first inlet liquid chamber; a second valve core, controlling liquid inflow into the second inlet liquid chamber; a liquid drainage valve core, controlling liquid drainage; a rotary shaft includes a first impeller and a second impeller. The first impeller and the second impeller alternately control flow to the first inlet liquid chamber and the second inlet liquid chamber and to the second inlet liquid chamber and the mixing chamber. The first impeller and the second impeller are symmetrically about the rotary shaft; when the first inlet liquid chamber and the second inlet liquid chamber are communicated, the second valve core closes the second inlet liquid chamber and the mixing chamber.

Abstract: A volume liquid fixed-ratio multi-batch mixing valve includes a valve body, including a first inlet liquid chamber, a second inlet liquid chamber and a mixing chamber; a first valve core, controlling liquid inflow into the first inlet liquid chamber; a second valve core, controlling liquid inflow into the second inlet liquid chamber; a liquid drainage valve core, controlling liquid drainage; a rotary shaft includes a first impeller and a second impeller. The first impeller and the second impeller alternately control flow to the first inlet liquid chamber and the second inlet liquid chamber and to the second inlet liquid chamber and the mixing chamber. The first impeller and the second impeller are symmetrically about the rotary shaft; when the first inlet liquid chamber and the second inlet liquid chamber are communicated, the second valve core closes the second inlet liquid chamber and the mixing chamber.

Abstract: A synthesized grating is provided comprising a substrate/layer, and a plurality of alternating aperiodic non-uniform low and high index profiles on a surface of the substrate/layer defining a transmission/reflection spectrum for one of either single or multi-frequency operation of said grating in an optical cavity. A method is also provided for designing the synthesized grating, comprising determining a grating structure of given profiles through analysis of an optimized weighted sum and mapping the grating profile to said surface with the plurality of alternating non-uniform low and high index profiles.

Abstract: An image processing method includes controlling a zoom lens carried by a gimbal to capture a reference image at a first focal range, adjusting the zoom lens to a second focal range, controlling the zoom lens to capture a plurality of far-focus images of different photographing ranges at the second focal range, stitching the plurality of far-focus images to form a stitched image, and processing the reference image and the stitched image to obtain a target reconstructed image. A focal length of the zoom lens corresponding to the second focal range is greater than a focal length of the zoom lens corresponding to the first focal range.

Abstract: An image processing method includes obtaining a first band image and a second band image, performing transparency processing on the first band image to obtain an intermediate image, and superimposing the intermediate image and the second band image to obtain a target image. The present disclosure also provide an image processing device and an unmanned aerial vehicle using the method above.

Abstract: A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

Abstract: A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

Abstract: A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

Abstract: A technique for narrowing a linewidth of a plurality of lines of a coherent comb laser (CCL) concurrently comprises providing a mode-locked semiconductor coherent comb laser (CCL) adapted to output of at least 4 mode-locked lines; tapping a fraction of a power from the CCL from the laser cavity to form a tapped beam; propagating the tapped beam to an attenuator to produce an attenuated beam; and reinserting the attenuated beam into the laser cavity, where the reinserted beam has a power less than 10% of a power of the tapped beam. The reinsertion allows the CCL to be operated to output the mode-locked lines, each with a linewidth of less than 80% of the original linewidth. By propagating the tapped and attenuated beams on a solid waveguide, and ensuring that the secondary cavity is polarization maintaining, improved stability of the linewidth narrowing is ensured.

Abstract: A multi-band (multi-color) multiwavelength mode locked laser diode is provided by dynamic phase compensation of a quantum dot active medium. The laser diode is provided with a PIN diode structure where the active medium consists of a plurality of layers of quantum dots such as those produced by self-assembly from known chemical beam epitaxy methods. The multiplicity of bands may be produced by AC Stark splitting, frequency selective attenuation, or by the inclusion of multiple different layers having different, respective, peak ASE emissions. Dispersion compensation within laser facets, waveguides, and the optically active media permit the selection of a fixed dispersion within the cavity. A dynamic group phase change induced by the AC Stark effect permits compensation of the fixed dispersion sufficiently to produce an intraband mode-locked laser. Even interband mode locking was observed.

Abstract: Methods and devices for providing a multiwavelength laser which may be used for multicasting and other optical communications uses. The present invention provides a quantum dot based multiwavelength laser with a monolithic gain block. The Fabry-Perot gain block has both upper and lower InP cladding layers. The laser system has a middle quantum dot layer with multiple stacked layers of InAs quantum dots embedded in InGaAsP. When provided with a CW injection current, the laser system produces an output spectra with equally spaced multiple emission peaks. With an input optical data signal applied to the laser system, the laser system duplicates the data in the input signal across multiple different wavelengths.

Abstract: A multi-band (multi-colour) multiwavelength mode locked laser diode is provided by dynamic phase compensation of a quantum dot active medium. The laser diode is provided with a PIN diode structure where the active medium consists of a plurality of layers of quantum dots such as those produced by self-assembly from known chemical beam epitaxy methods. The multiplicity of bands may be produced by AC Stark splitting, frequency selective attenuation, or by the inclusion of multiple different layers having different, respective, peak ASE emissions. Dispersion compensation within laser facets, waveguides, and the optically active media permit the selection of a fixed dispersion within the cavity. A dynamic group phase change induced by the AC Stark effect permits compensation of the fixed dispersion sufficiently to produce an intraband mode-locked laser. Even interband mode locking was observed.

Abstract: Methods and devices for providing a multiwavelength laser which may be used for multicasting and other optical communications uses. The present invention provides a quantum dot based multiwavelength laser with a monolithic gain block. The Fabry-Perot gain block has both upper and lower InP cladding layers. The laser system has a middle quantum dot layer with multiple stacked layers of InAs quantum dots embedded in InGaAsP. When provided with a CW injection current, the laser system produces an output spectra with equally spaced multiple emission peaks. With an input optical data signal applied to the laser system, the laser system duplicates the data in the input signal across multiple different wavelengths.

Abstract: A compact interrogator for the simultaneous interrogation of multi wavelength-modulated fiber optical sensors, includes a planar waveguide based demultiplexer receiving input signals from the sensors. An array of detectors is coupled to output waveguides of the demultiplexer corresponding to different nominal wavelengths. A tuning element matches the nominal wavelengths of the output waveguide to the input signals from the respective sensors to find the wavelengths of the individual sensors to be interrogated.

Abstract: A compact interrogator for the simultaneous interrogation of multi wavelength-modulated fiber optical sensors, includes a planar waveguide based demultiplexer receiving input signals from the sensors. An array of detectors is coupled to output waveguides of the demultiplexer corresponding to different nominal wavelengths. A tuning element matches the nominal wavelengths of the output waveguide to the input signals from the respective sensors to find the wavelengths of the individual sensors to be interrogated.

Abstract: Method and apparatus for real time measuring of an optical signal to noise ration (OSNR) of an optical channel is disclosed. The apparatus comprises a fiber Bragg grating for reflecting a signal component of the optical channel and for transmitting a noise component of the optical channel therethrough. Two photodetectors are provided disposed at two ends of the fiber Bragg grating for detecting a fraction of the reflected signal component and the transmitted noise component respectively. Electrical outputs of the photodetectors are communicated to a microprocessor for determining the OSNR. The invention provides a simple, compact, reliable, relatively fast and inexpensive technique to monitor OSNR.

Abstract: Polarization-mode dispersion (PMD) of an optical device, i.e. fiber or component is effected by launching a first pump laser beam of a fixed wavelength, a probe laser beam with a second fixed wavelength and a second pump laser beam having a variable wavelength and a polarization direction orthogonal to the other two beams into an optical device to generate three output signals which are input into a semiconductor optical amplifier to generate four-wave mixing (FWM) products. The average PMD of the device is computed by measuring the power of the FWM products versus the wavelength of the second pump laser beam.