A device for fluid analysis including an integrated computational element (ICE), a sample cell that optically interacts the ICE with a sample to generate a computation light associated with a characteristic of the sample, and a fiber sensor that receives the computation light and converts the computation light into a heat, is provided. The fiber sensor is coupled with a detector through an optical link, and is configured to return a portion of probe light through the optical link to the detector based on the heat converted. A method for using the device for performing fluid analysis is provided. A system for fluid analysis including at least one device as above is also provided.

Coated optical fibers and uses of such fibers as sensors in high temperature and/or high pressure environments. The coated optical fiber has improved sensing properties at elevated pressure and/or temperature, such as enhanced acoustic sensitivity and/or a reduced loss in acoustic sensitivity. The use of the coated optical fibers in various sensing applications that require operation under elevated pressure and/or temperature, such as, acoustic sensors for various geological, security, military, aerospace, marine, and oil and gas applications are also provided.

A system and method for shape sensing with optical fiber include collecting (610) shape data from a shape sensing optical fiber device. The shape data are tested (620) to determine data positions that exceed an acceptable threshold based on geometrical expectations of the shape data. The shape data corresponding to the data positions that exceed an acceptable threshold are rejected (640). Acceptable shape data are rendered (650) to provide a stable shape sensing data set.

A phase controller for controlling the phase of a light signal in a surface waveguide and a method for its fabrication are disclosed. The phase controller controls the phase of the light signal by inducing stress in the waveguide structure, thereby controlling the refractive indices of at least some of its constituent layers. The phase controller includes a phase-control element formed on topographic features of the top cladding of the waveguide, where these features (1) provide a shape to the phase-control element that matches the shape of the mode field of the light signal and (2) give rise to stress-concentration points that focus and direct induced stress into specific regions of the waveguide structure, thereby providing highly efficient phase control. As a result, the phase controller can operate at a lower voltage, lower power, and/or over a shorter interaction length than integrated-optic phase controllers of the prior art.

A method, includes: detecting one or more properties of a waveguide having a downhole end and an uphole end; and responsive to the detected one or more properties, positioning into a passage of a wellbore the waveguide to minimize tension thereof.

In the examples provided herein, a polarization diversity receiver system includes a loop waveguide, and a two-dimensional grating coupler formed on the loop waveguide to couple light impinging on the grating coupler having a first polarization into the loop waveguide in a first direction, and to couple light having a second polarization orthogonal to the first polarization into the loop waveguide in a second direction. The system also includes a first output waveguide positioned near the loop waveguide in a first coupling region, a first distributed perturbation having a first resonant wavelength in the first coupling region to cause coupling of light at the first resonant wavelength between the loop waveguide and the first output waveguide, and a first photodetector to detect light propagating out of a first end and a second end of the first output waveguide.

Unique gas cell constructions based on a hollow-core photonic crystal fiber are used, for example, inside a fiber ring laser cavity as an intracavity gas cell. In one embodiment, two simple terminal blocks are coupled to opposite ends of the hollow-core photonic crystal fiber. Each block features a main through-bore with an optical window at one end and an optical fiber chuck fitted at the other end, while a transverse bore intersects the main bore and features a gas fitting for connection to a gas source or vacuum pump. In another embodiment, the hollow-core photonic crystal fiber is contained within an enclosure whose exterior walls are fitted with optical windows and gas ports. Inside the enclosure, fiber clamps supports the ends of the hollow-core photonic crystal fiber at positions adjacent to an in alignment with the optical windows.

Provided are a Bragg grating and a spectroscopy device including the same. The Bragg grating is disposed at each of opposite ends of a resonator for reflecting light of a certain wavelength band and includes a core member extending from a waveguide of the resonator in a lengthwise direction of the waveguide; a plurality of first refractive members protruding from the core member and spaced apart from each other along the lengthwise direction; and a second refractive member filling spaces between the first refractive members and having a refractive index different from a refractive index of the first refractive members.

An optical fiber for converting a Gaussian laser beam into a Bessel laser beam may include a first segment optically coupled to a second segment with a transition region, the first segment having a first outer diameter greater than a second outer diameter of the second segment. The first segment may include a first core portion with a first cladding portion extending around the first core portion. The second segment may include a second core portion with a second cladding portion extending around the second core portion. The optical fiber may have a non-axisymmetric refractive index profile or may be coupled to an end cap with a non-axisymmetric refractive index profile.

Optical sensors having one or more soluble coatings thereon are used to detect the presence of a degrading fluid. In a generalized embodiment, the fiber optic sensor includes a fiber optic cable having two strain sensor positioned therein. A soluble layer is positioned over one of the strain sensor. Due to the presence of the soluble layer, the covered strain sensor optically responds differently than the other strain sensor to changes in pressure, strain and temperature. In the presence of a degrading fluid, the soluble layer degrades and ultimately dissolves, thereby changing the optical response of the previously covered strain sensor. When the soluble layer is dissolved, the strain induced by the soluble layer relaxes, thus causing a wavelength shift in the signal of the grating. By monitoring the wavelength shifts of both strain sensors, the fiber optic sensor acts as a detector for the presence of the degrading fluid.