A laser interferometer that includes a laser light source configured to emit emission light, a light splitter configured to split the emission light into first split light, and second split light incident on an object to be measured, a light modulator disposed on an optical path on which the first split light advances, and configured to modulate the first split light into a reference light having a different frequency from a frequency of the first split light, an optical path length change unit provided between the light splitter and the light modulator, and configured to change a first optical path length, the first optical path length being an optical path length between the light splitter and the light modulator, a photoreceptor configured to receive an interference light of the reference light and an object light generated by reflecting the emission light at the object to be measured, and to output a light reception signal, and a controller configured to control operation of the optical path length change unit in accordance with a second optical path length, the second optical path length being an optical path length between the light splitter and the object to be measured.

The disclosed embodiments generally relate to extruding multiple layers of micro- to nano-polymer layers in a tubular shape. In particular, the aspects of the disclosed embodiments are directed to a method for producing a Bragg reflector comprising co-extrusion of micro- to nano-polymer layers in a tubular shape.

A sensor (10) comprises a waveguide (20) having a longitudinal axis and an end face (21), the waveguide (20) comprising a Bragg grating (23). The sensor comprises at least one reflector (24) on the end face (21) of the waveguide (20). An optical resonator (25) is formed by the Bragg grating (23), the at least one reflector (24), and an inner portion of the optical resonator (25) between the Bragg grating (23) and the at least one reflector (24). The inner portion of the optical resonator (25) extends within a portion of the waveguide (20). The sensor (10) comprises a detector (32) configured to detect at least one spectral characteristic of the optical resonator (25) or a change of at least one spectral characteristic of the optical resonator (25).

An optical guidewire system employs an optical guidewire (10), an optical guidewire controller (12), a guide interface (13) and an optical connector (15). The optical guidewire (10) is for advancing a catheter (20) to a target region relative to a distal end of the optical guidewire (10), wherein the optical guidewire (10) includes one or more guidewire fiber cores (11) for generating an encoded optical signal (16) indicative of a shape of the optical guidewire (10). The optical guidewire controller (12) is responsive to the encoded optical signal (16) for reconstructing the shape of the optical guidewire (10). The guidewire interface (13) includes one or more interface fiber core(s) (14) optically coupled to the optical guidewire controller (12). The optical connector (15) facilitates a connection, disconnection and reconnection of the optical guidewire (10) to the guidewire interface (13) that enables a backloading the catheter (20) on the optical guidewire (10).

Systems and methods are described, and one method includes providing an optical fiber extending into a chamber with a volume of the gas; passing an optical beam, from an optical source, through the optical fiber; applying a spectral analysis to the optical beam as received after passing through the optical fiber, and outputting a corresponding spectral analysis signal; and determining, based on the output spectral analysis signal, whether a liquid is carried by the volume of the gas.

An optical system performs a method for measuring an acoustic signal in a wellbore. The optical system includes a light source, an optical fiber and a detector. The light source generates a light pulse. The optical fiber has a first end for receiving the light pulse from the light source and a plurality of enhancement scatterers spaced along a length of the optical fiber for reflecting the light pulse. A longitudinal density of the enhancement scatterers increases with a distance from the first end to increase a signal enhancement generated by the enhancement scatterers distal from the first end. The detector is at the first end of the optical fiber and measures a reflection of the light pulse at the enhancement scatterers to determine the acoustic signal.

The disclosed embodiments generally relate to extruding multiple layers of micro- to nanopolymer layers in a tubular shape. In particular, the aspects of the disclosed embodiments are directed to a method for producing a Bragg reflector comprising co-extrusion of micro- to nanopolymer layers in a tubular shape.

Improvements to gratings for use in waveguides and methods of producing them are described herein. Deep surface relief gratings (SRGs) may offer many advantages over conventional SRGs and Bragg gratings, an important one being a higher S-diffraction efficiency. In one embodiment, deep SRGs can be implemented as polymer surface relief gratings or evacuated Bragg gratings (EBGs). EBGs can be formed by first recording a holographic polymer dispersed liquid crystal (HPDLC) grating. Removing the liquid crystal from the cured grating provides a polymer surface relief grating. Polymer surface relief gratings have many applications including for use in waveguide-based displays.

An endoscope can include an elongated endoscope body. An optical fiber can extend along the endoscope body. The optical fiber can direct therapeutic light and illumination light longitudinally along the optical fiber to a distal portion of the endoscope body. The therapeutic light and the illumination light can have different wavelengths. A wavelength-sensitive light separator, disposed at a distal portion of the optical fiber, can direct the illumination light to exit the optical fiber laterally through a lateral side of the optical fiber at the distal portion of the optical fiber and permit the therapeutic light to exit the optical fiber longitudinally through a distal end of the optical fiber. Examples of suitable wavelength-sensitive light separators can include one or more fiber Bragg gratings that can be obliquely angled, or a diffraction grating disposed on a lateral edge of a length of coreless fiber.

An optical fiber sensor includes an optical fiber. The optical fiber includes a cladding having a cladding refractive index, and a plurality of fiber cores embedded in the cladding and extending along a longitudinal axis of the optical fiber. The plurality of fiber cores include a first subset of at least one first fiber core and a second subset of at least one second fiber core. The at least one first fiber core has a first core refractive index different from the cladding refractive index and a first core radius in a direction transverse to the longitudinal axis. The at least one second fiber core has a second core refractive index different from the cladding refractive index and a second core radius transverse to the longitudinal axis. The second core refractive index and the second core radius differ from the first core refractive index and the first core radius such that a temperature sensitivity of the at least one second fiber core differs from the temperature sensitivity of the first fiber core.