An apparatus for use with a pulsed laser source for forming an optical grating in a target includes an adjustable telescope having an element with a negative optical power, for generation of a diverging optical beam, so that the optical beam has adjustable divergence upon exiting the telescope while focusing of light inside the telescope is avoided. A transmission diffraction grating is disposed in the optical beam exiting the telescope, for forming an optical interference pattern on the target. Optical gratings with different grating periods may be formed by adjusting the divergence of the optical beam exiting the telescope. Lack of tight focal spots inside the telescope enables use of ultrashort pulse duration, high peak intensity laser sources.

Small profile apparatus for pressure and/or temperature sensing within a wellbore are provided. The apparatus may include optical sensing assemblies designed for inclusion in traditional or coiled production tubing deployments and suitable for use in high pressure, high temperature environments. One example assembly generally includes a housing having a divider for separating a first volume from a second volume inside the housing, a compressible element disposed in the first volume, wherein a first end of the compressible element is coupled to the divider and a second of the compressible element is sealed, and a large diameter optical waveguide disposed in an internal volume of the compressible element. The waveguide typically includes a first portion with a first grating and a second portion with a second grating, wherein the first portion has a greater outer diameter than the second portion.

A medical device operating as a stylet is described. The medical device can include an insulating layer (or sheath) encapsulating both a multi-core optical fiber and a conductive medium. The optical fiber can include a cladding and a plurality of core fibers spatially arranged within the cladding. Each of the core fibers can include a plurality of sensors distributed along a longitudinal length of that corresponding core fiber and each of these sensors can be configured to: (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber. The conductive medium can provide a pathway for electrical signals detected at a distal portion of the conductive medium. The conductive medium may be concentric to the cladding, but separate and adjust thereto.

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.

The image observation apparatus introduces an object light, which is at least part of an object illumination light emitted from a light source and projected onto an object and which is reflected by the object, through a first optical waveguide to an image sensor, introduces a reference light, which is emitted from the light source and passes through an optical path different from that of the object light, to the image sensor, and records an interference fringe through the image sensor as a hologram. The apparatus forms the recorded hologram on a spatial light modulator and illuminate the modulator with a hologram illumination light corresponding to the reference light to generate a reconstruction light, and causes the reconstruction light entering a second optical waveguide optically equivalent to the first optical waveguide and exiting from the second optical waveguide to form an object reconstructed image.

A multimode (MM) fiber oscillator is configured with MM active fiber doped with light emitters, a pair of MM passive fibers spliced to respective opposite ends of the MM active fiber, and a plurality of MM fiber Bragg gratings (FBG) written in respective cores of the MM passive fibers to provide a resonant cavity. The passive and active fibers are configured with respective cores which are dimensioned with respective diameters matching one another and substantially identical numerical apertures.

A sensor system includes a radiation source, an optical fiber, and a detection device. The radiation source is arranged to emit pulses of radiation. The optical fiber comprises a first end and a core. The first end is arranged to receive pulses of radiation output from the radiation source such that, in use, the pulses of radiation are coupled into the fiber. The core is arranged to support propagation of the pulses of radiation along the fiber. The core includes a plurality of reflectors each comprising a portion of the core having a refractive index which is different to the refractive index of adjacent regions of the core. Reflections of a pulse of radiation from adjacent reflectors output at the first end of the fiber are resolvable from each other in the time domain. The detection device is arranged to measure radiation output from the first end of the fiber and resolve radiation reflected at different locations in the core of the fiber.

A medical device operating as a stylet is described. The medical device can include an insulating layer (or sheath) encapsulating both a multi-core optical fiber and a conductive medium. The optical fiber can include a cladding and a plurality of core fibers spatially arranged within the cladding. Each of the core fibers can include a plurality of sensors distributed along a longitudinal length of that corresponding core fiber and each of these sensors can be configured to: (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber. The conductive medium can provide a pathway for electrical signals detected at a distal portion of the conductive medium. The conductive medium may be concentric to the cladding, but separate and adjust thereto.

An optical device which is packaged, a receiver device, a transceiver device, a communication system, a terminal device, and an optical system are provided. The optical device includes a waveguide and a magnetic element. The waveguide includes a core in which light propagates and a clad which covers the core. The core includes a diffraction grating on a first surface. The magnetic element is located above the first surface in the clad. The magnetic element includes a first ferromagnetic layer, a second ferromagnetic layer, and a spacer layer which is located between the first ferromagnetic layer and the second ferromagnetic layer.

A system and method directed to detecting placement of a medical device within a patient body, the system including a medical device including an optical fiber having core fibers. Each of the one or more core fibers can include a plurality of sensors each configured to reflect a light signal having an altered characteristic due to strain experienced by the optical fiber. The system can further include logic configured to determine a 3D shape of the medical device in accordance with the strain of the optical fiber. The logic can be configured to define a reference plane for the 3D shape and render an image of the 3D shape on a display of the system in accordance with the reference plane.