Systems and methods are described, and one method includes passing an optical beam through a volume of the gas to a reception surface, applying spectroanalysis to the optical beam received at the reception surface, and determining from the spectroanalysis whether a liquid is carried by the volume of the gas.

Methods and devices for a single wavelength fiber optic sensor system are described. Sensing is based on relative shift in spectral responses of two co-located fiber gratings (FBGs) within a fiber optic cable and measured at one measurement wavelength. Under a range of conditions of interest, the shift in spectral responses maintains the measurement wavelength within respective slopes of the spectral responses. A normalized difference in reflected power is used to desensitize the measurement from any variation in power of the single laser power and/or in loss through the fiber optic cable. Several pairs of co-located FBGs may be used within the same fiber optic cable, each pair used for sensing at a corresponding location. An OTDR system couples light pulses at the measurement wavelength to the fiber optic cable, and measures amplitudes and timing of corresponding reflected light pulses to perform the normalized difference.

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.

A surgical robotic user input apparatus has a fiber optic cable with a handheld user input device attached at one end, and a connector attached at another end. Multiple intrinsic sensors, such as fiber Bragg grating sensors, are in the fiber optic cable. The intrinsic sensors are used to detect a pose of the handheld user input device. Other embodiments are also described and claimed.

A multimode laser that generates laser emissions that are transmitted into an optical coupling then an optical filter to test for failures or faults within that optical filter is provided herein. Multimode lasers generate emissions which many different modes are present in the gain curve. Due to this, typical multi-mode laser failure-cases can be observed in the output frequency signal of laser emissions passing through an optical component. By using a spectrometer to analyze the exiting laser wavelengths, specific failure-cases of the optical component can be identified and related to root causes.

A distributed acoustic system (DAS) may comprise an interrogator and an umbilical line attached at one end to the interrogator, a downhole fiber attached to the umbilical line at the end opposite the interrogator. The interrogator may further include a proximal circulator, a distal circulator connected to the proximal circulator by a first fiber optic cable, and a second fiber optic cable connecting the proximal circulator and the distal circulator.

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 fiber-optic system for use in optical sensing includes a multicore sensing fiber having at least two cores of which each of the at least two cores has a first core diameter, and a multicore lead-in fiber having at least two cores including a position corresponding with the position of the at least two cores of the multicore sensing fiber. Each of the at least two cores of the multicore lead-in fiber have a second core diameter. The second core diameter is substantially larger than the first core diameter. The system further includes an alignment means for aligning the multicore sensing fiber and the multicore lead-in fiber so that the lead-in fiber and the multicore sensing fiber are configured for coupling radiation between the fibers through the cores.

An apparatuses relating generally to a test wafer, processing chambers, and method relating generally to monitoring or calibrating a processing chamber, are described. In one such an apparatus for a test wafer, there is a platform. An optical fiber with Fiber Bragg Grating sensors is located over the platform. A layer of material is located over the platform and over the optical fiber.

Disclosed are an apparatus for measuring a displacement using a fiber Bragg grating sensor, which is applied to a strain sensor using the fiber Bragg grating sensor, and a method of controlling sensitivity and durability of the same. The apparatus includes: a case forming an external appearance; third and fourth optical fibers having mutually different numbers of strands and installed in the case while being spaced apart from each other by a predetermined interval; and a connection unit installed between the third and fourth optical fibers and fixed at a predetermined position by tension applied to the third and fourth optical fibers, wherein the fiber Bragg grating sensor is installed to one selected from the pair of optical fibers having mutually different numbers of strands, so that measurement sensitivity and durability are controllable.