Some embodiments of the disclosure provides a method for preparing a sensing unit of a fiber-optic Fabry-Perot pressure sensor. The method includes the following steps. Preparing a first quartz sheet and a second quartz sheet, polishing the upper surface of the first quartz sheet, and polishing the upper surface of the second quartz sheet. Fabricating a plurality of grooves in the upper surface of the first quartz sheet. Fabricating through holes in the lower surface of the first quartz sheet, each of the through holes being coaxial with a corresponding groove and communicating with the corresponding groove. Combining the upper surface of the second quartz sheet with the upper surface of the first quartz sheet to form a laminated body. Cutting the plurality of grooves of the laminated body to obtain a plurality of sensing units.

Method for setting parameters for individual adaptation of an audio signal, including: performing a first listening test with the substeps: playing a plurality of first audio signals having different levels; obtaining feedback per frequency range from an individual which of the plurality of first acoustic signals is above an individual listening threshold; and using the lowest level of the different levels for which feedback is available as a level for the individual listening threshold per frequency range; performing adaptation of a second audio signal with the substeps: playing the second audio signal according to a total volume level considering a sound adaptation characteristic map; and varying the sound adaptation characteristic wherein the levels for the individual listening thresholds are used as minimum output levels in the sound adaptation characteristic map.

An optical sensor includes a tube-shaped base formed from a metal, an optical fiber member received inside the base, and a sensor head formed from monocrystalline alumina and bonded to the base to be optically connected with the optical fiber member. The sensor head is provided with a first cavity including a first reflection surface configured to reflect a part of light introduced through the optical fiber member and a second reflection surface provided facing the first reflection surface and configured to reflect a part of the light reflected by the first reflection surface. A first interference light produced by an interference between the light reflected by the first reflection surface and the light reflected by the second reflection surface is output from the first cavity.

An air pressure sensor based on a suspended-core fiber and a side-hole fiber is provided and includes a broadband light source, an optical fiber circulator, a sensing head and a spectrometer; the optical fiber circulator is connected with the broadband light source, the sensing head and the spectrometer; the sensing head includes a single mode fiber, a multimode fiber, the suspended-core fiber and the side-hole fiber; the single mode fiber is connected with the suspended-core fiber through the multimode fiber; and the multimode fiber is connected with the side-hole fiber through the suspended-core fiber. The sensor uses a fabrication method of fiber fusion, and the operation is simple; the sensor has advantages of small volume, compact structure and convenient use; the sensor has good stability without adhesive; additionally, parallel connection of double cavities could produce vernier effects, so the sensor has good contrast of interference spectrum and high sensitivity.

A method includes receiving wavelength domain data for a time step, performing a Discrete Fourier Transform (DFT) to transform the wavelength domain data for the time step into frequency domain data for the time step only for the limited set of frequency bins associated with a frequency of interest, calculating pressure based on the frequency domain data for the time step, and updating the frequency of interest and the limited set of frequency bins. The method includes repeating receiving wavelength data for subsequent time steps, performing a DFT to transform the wavelength data for the respective subsequent time steps, calculating pressure for each subsequent time step, and updating the frequency of interest and limited set of frequency bins for each subsequent time step. The method includes outputting pressure data based on calculating pressure for the subsequent time steps.

The invention relates to a method for integrating a sensor into a metal part, including: a)—the creation by additive printing of a first part (2) of the part, including a volume (4) for housing a sensor, this volume having a width greater than that of the sensor; b)—the deposition of the sensor in said housing volume; c)—the creation by additive printing of a second part (6) of the part, covering the sensor and the formation of a molten puddle in the housing volume (4), on either side of the sensor.

A optical sensor assembly is disclosed that includes a sensor diaphragm configured to deflect responsive to an applied stimulus. The sensor assembly includes a first Extrinsic Fabry-Perot Interferometer (EFPI) having a first optical cavity in communication with at least a portion of the sensor diaphragm, the first EFPI is configured to interact with light to produce a combined measurement light signal and a first common-mode light signal, the measurement light signal corresponding to the applied stimulus. The sensor assembly also includes a second EFPI having a second optical cavity, the second EFPI is configured to interact with light to produce a second common mode light signal for error correction. The sensor assembly may further include a sensing optical fiber in communication with the first EFPI; a reference optical fiber in communication with the second EFPI; and a glass header configured to support the sensing optical fiber and the reference optical fiber.

Certain example implementations of the disclosed technology include an optical-interferometer sensor assembly for measuring pressure or acceleration. The sensor assembly includes a diaphragm configured to deflect responsive to an applied stimulus, a diaphragm support structure in communication with the diaphragm, a sensing optical interferometer having a first optical cavity in communication with at least a portion of the diaphragm and the diaphragm support structure, and a reference optical interferometer having a second optical cavity in communication with the diaphragm support structure. The sensor assembly can include a sensing optical fiber in communication with the sensing optical interferometer and a reference optical fiber in communication with the reference optical interferometer. The sensor assembly can include a housing in communication with the diaphragm and the diaphragm support structure, and configured to reduce a thermal expansion mismatch in the sensor assembly.

A sensor for measuring pressure, temperature or both may be provided. The sensor may include a diaphragm that may respond to a change in temperature or pressure, a base connected to the diaphragm, a cavity, and an optical fiber that may conduct light reflected off of a surface of the diaphragm. The diaphragm and base may be sapphire elements. An interrogator may be provided for detecting a deflection of the diaphragm.

Methods, apparatus, and systems are provided for sensing pressure. One example apparatus includes a housing having a first port, a chamber disposed in the housing and having a second port, wherein the second port is coupled to the first port such that a volume inside the chamber is in fluid communication with an environment external to the housing, and a pressure sensor assembly at least partially disposed in the chamber and configured to sense a pressure of a fluid in the chamber. The chamber may be mechanically coupled to the housing via a portion of an exterior surface of the chamber such that a pressure response of the pressure sensor assembly is independent of extraneous loading on the housing.