A broadband interferometry for a measurement range extension beyond a coherence length of a light source includes a wavelength tunable laser as the light source outputting a coherence wavelength beam; and an interferometer disposed between the wavelength tunable laser and a target to be measured and including a reference arm, a measurement arm and a device combining a reference beam and measurement mean to produce a combined interference beam, wherein a local oscillation of the reference beam is replicated by a cavity multiplication or cascading optical delayed lines with a fiber optic cavity, and quantifiable optical properties including a wavelength group delay, a chromatic dispersion, a polarization mode dispersion and a model dispersion are inserted into the local oscillation of the reference beam to incrementally quantify the replicated copies of the local oscillation as the number of the delayed copies of the local oscillation increase for extension of a measurement rage to the target.

In an optical device, a base and a movable unit are constituted by a semiconductor substrate including a first semiconductor layer, an insulating layer, and a second semiconductor layer in this order from one side in a predetermined direction. The base is constituted by the first semiconductor layer, the insulating layer, and the second semiconductor layer. The movable unit includes an arrangement portion that is constituted by the second semiconductor layer. The optical function unit is disposed on a surface of the arrangement portion on the one side. The first semiconductor layer that constitutes the base is thicker than the second semiconductor layer that constitutes the base. A surface of the base on the one side is located more to the one side than the optical function unit.

An optical module includes a mirror unit and a beam splitter unit. The mirror unit includes a base with a main surface, a movable mirror, a first fixed mirror, and a drive unit. The beam splitter unit constitutes a first interference optical system for measurement light along with the movable mirror and the first fixed mirror. A mirror surface of the movable mirror and a mirror surface of the first fixed mirror follow a plane parallel to the main surface and face one side in a first direction perpendicular to the main surface. The movable mirror, the drive unit, and at least a part of an optical path between the beam splitter unit and the first fixed mirror are disposed in an airtight space.

A mirror unit 2 includes a mirror device 20 including a base 21 and a movable mirror 22, an optical function member 13, and a fixed mirror 16 that is disposed on a side opposite to the mirror device 20 with respect to the optical function member 13. The mirror device 20 is provided with a light passage portion 24 that constitutes a first portion of an optical path between the beam splitter unit 3 and the fixed mirror 16. The optical function member 13 is provided with a light transmitting portion 14 that constitutes a second portion of the optical path between the beam splitter unit 3 and the fixed mirror 16. A second surface 21b of the base 21 and a third surface 13a of the optical function member 13 are joined to each other.

A blade tip measurement system includes a case and a blade that rotates within the case, the blade having an outer blade tip surface that has a clearance distance from an inner surface of the case. A light source emits light along an optical path that is directed toward the outer blade tip surface by a lens, and the outer blade tip surface reflects the light back along the optical path. An optical interferometer generates an interference pattern using the reflected light, and a photoreceiver receives the interference pattern. A complex logic device determines the clearance distance of the blade tip surface from the inner surface of the case based on the interference pattern. The interferometer may be a Fabry-Perot optical interferometer formed using a window positioned between the lens and the blade tip surface, or a Michelson interferometer formed using a reference optical path. The system may alternatively include an optical time of flight measurement of the blade tip clearance. The system further may include an abradable substrate having an optical fiber array of optical fibers at different depths, whereby the blade tip clearance is determinable based on which of the optical fibers are abraded as the blade tip rotates.

A measurement apparatus includes a light source that emits light, a spectroscopic element that is configured to transmit light of a predetermined wavelength out of the light emitted from the light source portion, and capable of changing the predetermined wavelength of the light to be transmitted within a predetermined wavelength range, an interference optical system which separates light emitted from the spectroscopic element into measurement light irradiated on a measurement target and reference light reflected by a reference body, and generates interference light obtained by combining the measurement light reflected by the measurement target and the reference light reflected by the reference body, an image sensor that receives the interference light, and one or more processors configured to calculate a position of the measurement target based on spectrum information indicating a change in a received light quantity at the light receiving portion when the predetermined wavelength of the light transmitted through the spectroscopic element is changed.

The present disclosure provides a compressed ultrafast imaging velocity interferometer system for any reflector, comprising a light source and target system, an etalon interference system, a compressed ultrafast imaging system, a timing control system and a data processing system. An imaging device in the traditional imaging velocity interferometer system for any reflector is replaced by a compressed ultrafast imaging system, a compressed ultrafast Photography (CUP) is introduced in an imaging process, multi-frame images, i.e. three-dimensional images for two-dimensional space and one-dimensional time, are reconstructed via a single measurement by a CUP-VISAR two-dimensional ultrafast dynamic image imaging, a complete dynamic process of a two-dimensional interference fringes image is restored, and spatiotemporal evolution information of a shock wave is effectively acquired, improving an imaging performance of the imaging velocity interferometer system for any reflector in dimension, and achieving a goal that could not be achieved before.

An optical module includes a mirror unit and a beam splitter unit. The mirror unit includes a base with a main surface, a movable mirror, a first fixed mirror, and a drive unit. The beam splitter unit constitutes a first interference optical system for measurement light along with the movable mirror and the first fixed mirror. A mirror surface of the movable mirror and a mirror surface of the first fixed mirror follow a plane parallel to the main surface and face one side in a first direction perpendicular to the main surface. The movable mirror, the drive unit, and at least a part of an optical path between the beam splitter unit and the first fixed mirror are disposed in an airtight space.

A system and method for generating, enhancing, and detecting the amplitude and phase modulation of a laser under a condition of self-mixing is provided. The system may comprise a laser and a detector to extract the characteristic self-mix signal, which is then interpreted using algorithms implemented in hardware or software. In the case of the laser being a Vertical Cavity Surface Emitting laser (VCSEL), the output signal can be detected by monitoring the surface light emission by means of a beam splitter, or in some embodiments as emission from the bottom surface of the laser. In some embodiments, the system may further comprise a wavelength filter such as an etalon in the signal path.

A fiber-optic sensors for measuring deformation, intended to operate in a harsh environment is provided. The sensor comprises a Fabry-Perot-cavity-based optical measurement head, a linking optical fiber and an expansion reserve case, the case comprising a segment of the linking optical fiber. The inside thickness of the case is comprised between one and several millimeters, the case being flat and of shape referred to as bicorne shape, the shape comprising a convex central portion and two concave symmetric ends, the optical fiber forming, inside the bicorne, one and only one arch, the segment of the optical fiber being, in addition, tangent to the internal surfaces of the reserve case, whatever the temperature conditions.