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4612 results about "Resonant cavity" patented technology

A resonant cavity forms a means of storing electromagnetic energy, at a particular frequency within a small bandwidth. A resonant cavity must be constructed of a good conductor, and the shape of the cavity is related to the frequency that it can resonate at.

Coupled cavity high power semiconductor laser

An active gain region sandwiched between a 100% reflective bottom Bragg mirror and an intermediate partially reflecting Bragg mirror is formed on a lower surface of a supporting substrate, to thereby provide the first (“active”) resonator cavity of a high power coupled cavity surface emitting laser device. The reflectivity of the intermediate mirror is kept low enough so that laser oscillation within the active gain region will not occur. The substrate is entirely outside the active cavity but is contained within a second (“passive”) resonator cavity defined by the intermediate mirror and a partially reflecting output mirror, where it is subjected to only a fraction of the light intensity that is circulating in the gain region. In one embodiment, non-linear optical material inside each passive cavity of an array converts an IR fundamental wavelength of each laser device to a corresponding visible harmonic wavelength, and the external output cavity mirror comprises a Volume Bragg grating (VBG) or other similar optical component that is substantially reflective at the fundamental frequency and substantially transmissive at the harmonic frequency. The VBG used in an array of such devices may be either flat, which simplifies registration and alignment during manufacture, or may be configured to narrow the IR spectrum fed back into the active resonant cavity and to shape the spatial mode distribution inside the cavity, thereby reducing the size of the mode and compensating for any deformations in the semiconductor array.

Laser ignition

InactiveUS6676402B1Durable and reliable and economical ignitionEliminate needLaser detailsPulsating combustionResonant cavityLight beam
Sequenced pulses of light from an excitation laser with at least two resonator cavities with separate output couplers are directed through a light modulator and a first polarzing analyzer. A portion of the light not rejected by the first polarizing analyzer is transported through a first optical fiber into a first ignitor laser rod in an ignitor laser. Another portion of the light is rejected by the first polarizing analyzer and directed through a halfwave plate into a second polarization analyzer. A first portion of the output of the second polarization analyzer passes through the second polarization analyzer to a second, oscillator, laser rod in the ignitor laser. A second portion of the output of the second polarization analyzer is redirected by the second polarization analyzer to a second optical fiber which delays the beam before the beam is combined with output of the first ignitor laser rod. Output of the second laser rod in the ignitor laser is directed into the first ignitor laser rod which was energized by light passing through the first polarizing analyzer. Combined output of the first ignitor laser rod and output of the second optical fiber is focused into a combustible fuel where the first short duration, high peak power pulse from the ignitor laser ignites the fuel and the second long duration, low peak power pulse directly from the excitation laser sustains the combustion.

Electrooptically Bragg-reflector stopband-tunable optoelectronic device for high-speed data transfer

A device contains at least one wavelength-tunable multilayer interference reflector controlled by an applied voltage and at least one cavity. The stopband edge wavelength of the wavelength-tunable multilayer interference reflector is preferably electrooptically tuned using the quantum confined Stark effect in the vicinity of the cavity mode (or a composite cavity mode), resulting in a modulated transmittance of the multilayer interference reflector. A light-emitting medium is preferably introduced in the cavity or in one of the cavities permitting the optoelectronic device to work as an intensity-modulated light-emitting diode or diode laser by applying an injection current. The device preferably contains at least three electric contacts to apply forward or reverse bias and may operate as a vertical cavity surface emitting light-emitter or modulator or as an edge-emitting light emitter or modulator. Using a multilayer interference reflector containing tunable section allows also obtaining a wavelength-tunable laser or a wavelength-tunable resonant cavity photodetector in the case where the optical field profile in the active cavity or cavities is affected by the stopband wavelength shift. Adding additional modulator sections enables applications in semiconductor optical amplifiers, frequency converters or lock-in optical amplifiers.

Sensing method of optical-fiber Bragg grating laser device

The invention relates to a sensing method with an optical-fiber Bragg grating laser device. An optical-fiber Bragg grating is used as a reflector of the resonant cavity, an active optical fiber capable of generating sufficient gains is added, and a double wavelength/multiple wavelength optical-fiber Bragg grating laser device is formed under the action of a pump light source and used as a sensor. When the outside strain, temperature and other physical quantities act on the sensing system, the beat signal frequency among the double wavelength or multiple wavelength laser can shift, and counter stress, temperature and other physical parameters can be measured precisely by detecting the beat signal frequency information. The invention has the advantages of simple manufacture, stable and reliable operation, stable measurement result and high precision, and is free from the interference of light intensity, polarization and other optical information quantities. The multipoint distribution sensing measurement can be realized in a frequency-division multiplexing mode. An electrooptical modulator is added before the spectrum analyzer starts detection so as to randomly adjust the beat signal frequency, thereby greatly reducing the spectral range of the spectrum analyzer and reducing the detection cost.

III-V charge coupled device suitable for visible, near and far infra-red detection

A photon detector is obtained by using the intersubband absorption mechanism in a modulation doped quantum well(s). The modulation doping creates a very high electric field in the well which enables absorption of input TE polarized light and also conducts the carriers emitted from the well into the modulation doped layer from where they may recombine with carriers from the gate contact. Carriers are resupplied to the well by the generation of electrons across the energy gap of the quantum well material. The absorption is enhanced by the use of a resonant cavity in which the quantum well(s) are placed. The absorption and emission from the well creates a deficiency of charge in the quantum well proportional to the intensity of the input photon signal. The quantity of charge in the quantum well of each detector is converted to an output voltage by transferring the charge to the gate of an output amplifier. The detectors are arranged in the form of a 2D array with an output amplifier associated with the entire array or a row of the array as in the known charge coupled devices, or a separate amplifier could be dedicated to each pixel as in the known architecture of the active pixel device. This detector has the unique advantage of near room temperature operation because the dark current is limited to the generation across the semiconductor bandgap and not the emission over the quantum well barrier. The detector also has the advantage that the readout circuitry is implemented monolithically by the HFETs formed in the GaAs substrate simultaneously, with the detecting elements.

Method and device for curing fiber-reinforced resin-based composite material component by utilizing microwaves

The invention relates to a method and a device for curing a fiber-reinforced resin-based composite material component by utilizing microwaves. The microwaves which are generated by a microwave source with linearly-adjustable power are guided into a resonant cavity, and the microwaves penetrate through and heat the composite material, so that the composite material can be quickly cured and formed. By adopting the advanced octagonal microwave-mode resonant cavity, the uniformity of an electromagnetic field inside the device can be realized; the interference of the reflection wave on the microwave source can be reduced by adopting an automatic impedance matching system, so that the optimal transmission of the microwave power can be realized. A vacuum pipe connector and a temperature sensor are arranged on the inner side wall of the octagonal multi-mode resonant cavity, a glass worktable is arranged inside the resonant cavity, and the rotation of a ball screw is controlled through a stepper motor to control the back-forth movement of the worktable. A choking groove is adopted to prevent the leakage of the microwave. By adopting the method and the device, the problems of the traditional autoclave forming method that the time for manufacturing the fiber-reinforced composite material is long, the energy consumption is high and the heat is non-uniform can be solved, the curing time can be saved, and the quality and performance of the composite material component can be improved.

Dielectric materials high-temperature complex dielectric constant measurement method based on terminal short circuit method

The present invention provides a medium material high-temperature complex permittivity measurement method based on terminal short circuit and pertains to technology of microwave and millimeter wave dielectric material complex permittivity measurement. When the present invention adopts the terminal short circuit for measurement of high-temperature medium material complex permittivity, a heat dissipation wave guide, a heat insulation waveguide, a high-temperature waveguide with a certain length, and a coupling device, a short circuit board are together constitute a reactive type resonator, and dimensions and microwave loss of the resonator under different temperature can be obtained by measurement of resonance frequency and quality factor of the resonator, and the complex permittivity of the medium material under the temperature can be further measured. The present invention is suitable for the measurement of the medium material high-temperature complex permittivity of various frequency band based on the terminal short circuit, and meanwhile the present invention can measure the dimension and the microwave loss of the waveguide resonator under different temperature. As the present invention considers the changing of the dimension and the microwave loss of the waveguide resonator caused by the influence of the temperature, the present invention has higher measurement accuracy and smaller error.

Spectral measurement method based on optical frequency combs

The invention discloses a spectral measurement method based on optical frequency combs. The measurement method is characterized in that firstly, an annular laser resonant cavity based on a phase modulator is actively modulated by use of a first optical frequency comb controllable in time domain and frequency domain so that the annular laser resonant cavity is converted into a second optical frequency comb having tiny difference in repetition frequency with the first optical frequency comb, and spectrum detection is performed on the two optical frequency combs to obtain an interference signal carrying the information of a sample to be tested, and meanwhile, frequency beating is performed on the two optical frequency combs and continuous frequency stabilized laser, respectively, the difference frequency signal of two obtained beat frequency signals is mixed with the interference signal, and a signal obtained by virtue of detection mixing is taken as a spectral signal for Fourier analysis so as to reduce the optical information of the sample to be tested. The spectral measurement method has the advantages that the error of the spectral detection due to own phase drift of a dual-optical comb system can be eliminated, and therefore, the resolution and the detection accuracy of the spectral measurement can be improved.

Silicon-based multi-layer cavity filter

The invention discloses a silicon-based multi-layer cavity filter, which is formed by superposing more than two medium layers up and down, wherein a through hole is formed in each medium layer; an internal wall metal layer which is formed by using a silicon micro-machining technology is arranged on an internal wall of the through hole; an intermediate metal layer which is formed by using the silicon micro-machining technology is arranged between the two adjacent medium layers; an inter-stage coupling window is arranged on the intermediate metal layer; an upper surface of a top medium layer and a lower surface of a bottom medium layer are respectively provided with a surface metal layer which is formed by using the silicon micro-machining technology; a metal layer which is contacted with the upper and lower surfaces of each medium layer and an internal wall metal layer form a resonant cavity; and an input tap lead is arranged on one resonant cavity, and an output tap lead is arranged on another resonant cavity. The silicon-based multi-layer cavity filter is small in size, has a shielding function, can meet the accuracy requirement of microwave/millimeter wave frequency band, and is free from encapsulation, good in device consistency, compatible with an integrated circuit process, easy to implement system integration and convenient to assemble and debug.
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