Abstract: An optical fiber characteristic measurement device (1) includes a light detector (16) configured to detect Brillouin scattered light (LS) obtained by causing light to be incident on an optical fiber (FUT); a signal processor (18b) configured to obtain, on the basis of a detection signal (S1) which is output from the light detector, a first Brillouin gain spectrum (B1) which is a spectrum of the Brillouin scattered light obtained in a case where a spectral width of the light incident on the optical fiber is a first width and a second Brillouin gain spectrum (B2) which is a spectrum of the Brillouin scattered light obtained in a case where the spectral width of the light incident on the optical fiber is a second width larger than the first width; and a measurer (18c) configured to measure characteristics of the optical fiber on the basis of the first Brillouin gain spectrum and the second Brillouin gain spectrum.

Abstract: A laser light profile measuring device of the present disclosure includes a reflection attenuation part reflecting and attenuating at least part of laser light incident from a first direction in a direction different from the first direction to generate measurement target laser light traveling in the first direction, a capture unit placed on one side of the reflection attenuation part in the first direction and which captures the measurement target laser light, a cooling body covering at least part of the reflection attenuation part and the capture unit in a circumferential direction with respect to the first direction, a refrigerant supply unit forcibly feeding a refrigerant toward the cooling body, and a rotation support part supporting the reflection attenuation part, the cooling body, and the refrigerant supply unit to be rotatable around a rotation axis extending in a horizontal direction.

Abstract: A demultiplexed filtering method includes propagating an optical beam from an input optical fiber to a diffraction grating to produce a first and a second diffracted beam having a respective first center wavelength ?1 and a second center-wavelength ?2>?1 of the optical beam. The first diffracted beam propagates back toward the input optical fiber at a first diffracted angle determined in part by ?1 and a diffraction order m1 of the first diffracted beam. The second diffracted beam propagates back toward the input optical fiber at a second diffracted angle determined in part by ?2 and a diffraction order m2<m1. The method also includes (i) coupling the first diffracted beam into a first optical fiber of a one-dimensional optical-fiber array that includes the input optical fiber, and (ii) coupling the second diffracted beam into a second optical fiber of the one-dimensional optical-fiber array.

Abstract: A device includes a diffraction-based overlay (DBO) mark having an upper-layer pattern disposed over a lower-layer pattern, and having smallest dimension greater than about 5 micrometers. The device further includes a calibration mark having an upper-layer pattern disposed over a lower-layer pattern, positioned substantially at a center of the DBO mark, and having smallest dimension less than about ? the size of the smallest dimension of the DBO mark.

Abstract: A breast diffusion optical tomography (DOT) device includes a light source, a detector, a mechanical driver and a contour acquisitor without using optical fiber and reduce the system complexity. The light source includes M1 number of multi-wavelength near-infrared light emitters for a continuous-wave mode and M2 number of laser diodes of different wavelengths for a frequency-domain mode. The detector includes N1 number of silicon photomultipliers for detecting near-infrared light in the continuous-wave mode and N2 number of silicon photomultipliers for detecting near-infrared light in the frequency-domain mode. The mechanical driver adjusts a distance between the light source and the detector. The contour acquisitor obtains the geometry of a patient's breast for reconstruction. The DOT device uses amplitude and phase information obtained in the frequency-domain mode to estimate initial optical parameters of tissues and then apply for reconstruction in the continuous-wave mode.

Abstract: This application describes a fibre optic cable structure which is advantageous for distributed fibre optic sensing, for example distributed acoustic sensing (DAS). The fibre optic cable structure includes an optical fibre for distributed fibre optic sensing and is configured to comprise at least one longitudinal section of a first type, which exhibits a change in effective optical path length of the optical fibre of one polarity in response to a given applied force, and which is adjacent to at least one longitudinal section of a second type, which exhibits a change in effective optical path length of the optical fibre of the opposite polarity in response to an equivalent applied force. When used for DAS, the response of a sensing portion that includes sections of both the first and second types, will include or exclude certain wavenumber by summation, which provides a directional sensitivity to incident waves.

Abstract: A method and apparatus for determining a growth rate on a semiconductor substrate is described herein. The apparatus is an optical sensor, such as an optical growth rate sensor. The optical sensor is positioned in an exhaust of a deposition chamber. The optical sensor is self-heated using one or more internal heating elements, such as a resistive heating element. The internal heating elements are configured to heat a sensor coupon. A film is formed on the sensor coupon by exhaust gases flowed through the exhaust and is correlated to film growth on a substrate within a process volume of the deposition chamber.

Abstract: A method includes providing a cuvette containing a fluid sample having a first substance and emitting light from a light source through the cuvette containing the fluid sample for a duration of time. The cuvette is made of a material that at least partially dissolves in the presence of the first substance. Over the duration of time, the cuvette at least partially dissolves and an intensity of light that passes through the cuvette and the fluid sample changes at a rate. The method also includes receiving, by a light detector, the light that passed through the cuvette, measuring a change in intensity of the received light over the duration of time, and determining that the rate of change in intensity of the light over the duration of time is greater than a threshold rate of change.