In some examples, optical fiber identification and distance measurement may include utilizing a reflectometer and optical fiber connection device that includes a Rayleigh wavelength pass filter to pass, in one direction, an optical reflectometer signal to an optical fiber. The reflectometer and optical fiber connection device may include a Raman wavelength pass filter to filter out, in another direction, Rayleigh backscattering from the optical reflectometer signal. Further, the Raman wavelength pass filter may pass, in the another direction, a Raman Anti-Stokes signal from the optical fiber.

In some examples, optical fiber identification and distance measurement may include utilizing a reflectometer and optical fiber connection device that includes a Rayleigh wavelength pass filter to pass, in one direction, an optical reflectometer signal to an optical fiber. The reflectometer and optical fiber connection device may include a Raman wavelength pass filter to filter out, in another direction, Rayleigh backscattering from the optical reflectometer signal. Further, the Raman wavelength pass filter may pass, in the another direction, a Raman Anti-Stokes signal from the optical fiber.

A solution is provided comprising boron nitride nanotubes (BNNTs) in a liquid solvent. An optical waveguide, such as an optical fiber, is contacted with the solution so as to form a layer of the solution supported on at least a portion of the optical waveguide. The liquid solvent is then removed from the layer of the solution supported on the optical waveguide in order to form a coating of the BNNTs on the optical waveguide. Further provided is a BNNT coated optical waveguide for use as a sensor.

A long range optical fiber sensor such as a distributed acoustic sensor has a sensing fiber located remotely from the interrogator, with a length of transport fiber path connecting the two. Because no sensing is performed on the transport fiber then the pulse repetition rate from the interrogator can be high enough such that the pulse repetition rate and pulse power are optimised according to the sensing fiber length and hence sensing frequency response and sensitivity are also optimised according to the sensing fiber length.

The present disclosure is directed to enabling detection of microbending even in a case where a microbending loss varies.

The present disclosure relates to a device that measures a transmission loss in a measured optical fiber to be targeted, and detects microbending in the measured optical fiber based on periodicity of the transmission loss.

Provided is an apparatus for determining the temperature of at least one fluid. The apparatus includes an optical fiber. A first end of the optical fiber is connected to at least one fiber tip, and a first additional reflector is introduced into the at least one fiber tip at a first predetermined distance from an outer end of the at least one fiber tip. A second end of the optical fiber is connected to a processing apparatus. The processing apparatus includes an optical source. The optical source is configured to launch an optical signal into the optical fiber, and a coherent detector. The coherent detector is configured to determine the temperature of at least one fluid by receiving a first light signal that corresponds to parts of the optical signal that are reflected at the outer end of the at least one fiber tip when the at least one fiber tip is inserted into the at least one fluid and a second light signal that corresponds to parts of the optical signal that are reflected at the first additional reflector when the at least one fiber tip is inserted into the at least one fluid, determining a difference of the optical phases of the first light signal and the second light signal, and determining the temperature of the at least one fluid based on the difference of the optical phases of the first light signal and the second light signal.

Provided is an apparatus for determining the temperature of at least one fluid. The apparatus includes an optical fiber. A first end of the optical fiber is connected to at least one fiber tip, and a first additional reflector is introduced into the at least one fiber tip at a first predetermined distance from an outer end of the at least one fiber tip. A second end of the optical fiber is connected to a processing apparatus. The processing apparatus includes an optical source. The optical source is configured to launch an optical signal into the optical fiber, and a coherent detector. The coherent detector is configured to determine the temperature of at least one fluid by receiving a first light signal that corresponds to parts of the optical signal that are reflected at the outer end of the at least one fiber tip when the at least one fiber tip is inserted into the at least one fluid and a second light signal that corresponds to parts of the optical signal that are reflected at the first additional reflector when the at least one fiber tip is inserted into the at least one fluid, determining a difference of the optical phases of the first light signal and the second light signal, and determining the temperature of the at least one fluid based on the difference of the optical phases of the first light signal and the second light signal.

Temperature measurements of photonic circuit components may be performed optically, exploiting a temperature-dependent spectral property of the photonic device to be monitored itself, or of a separate optical temperature sensor placed in its vicinity. By facilitating measurements of the temperature of the individual photonic devices rather than merely the photonic circuit at large, such optical temperature measurements can provide more accurate temperature information and help improve thermal design.

A plasma processing chamber optical temperature sensor is disclosed. The plasma processing chamber optical temperature sensor includes a light source, a light detector, and a means for transmitting light through a wall of a plasma processing chamber. An optical temperature sensing element is thermally coupled to a plasma processing chamber component within the plasma processing chamber. The optical temperature sensing element includes a monolithic crystalline phosphor element configured to be excited by light from the light source and to emit light back to the light detector indicative of a temperature of the monolithic crystalline phosphor element.

A plasma processing chamber optical temperature sensor is disclosed. The plasma processing chamber optical temperature sensor includes a light source, a light detector, and a means for transmitting light through a wall of a plasma processing chamber. An optical temperature sensing element is thermally coupled to a plasma processing chamber component within the plasma processing chamber. The optical temperature sensing element includes a monolithic crystalline phosphor element configured to be excited by light from the light source and to emit light back to the light detector indicative of a temperature of the monolithic crystalline phosphor element.