Abstract: An optical sensor has a waveguide having a core, a cladding having an outer surface and a long period fiber grating. The core, the cladding and the long period fiber grating collectively provide at least two resonant wavelengths. The optical sensor also has binding sites on the outer surface of the cladding for binding to elements to be detected to the outer surface of the cladding. The cladding may be thinned down to a thickness sufficiently low produce the resonant wavelengths. The binding sites include agents for binding to the elements to be detected with the agents being covalently bonded to the surface of the cladding. Example binding sites can include bacteriophages for detecting E. coli bacteria, Palladium for detecting hydrogen, or synthetic DNA for detecting viruses of certain molecules for example.

Abstract: An optical sensor having dual resonant long period gratings (DRLPGs) separated by an inter-grating fiber spacing IGS of a length and material to provide temperature insensitivity over a wide wavelength range. The materials of the IGS and DRLPGs are such that the difference between the dn/dT of the core and the dn/dT of the cladding in the IGS is opposite in sign to that of the DRLPGs. The DRLPGs and the IGS are also composed of materials and have dimensions such that the turn-around points ?D, as well as the general functional form of the respective spectral variation of their propagation constant difference ?? versus wavelength are substantially similar.

Abstract: An optical sensor has a waveguide having a core, a cladding having an outer surface and a long period fiber grating. The core, the cladding and the long period fiber grating collectively provide at least two resonant wavelengths. The optical sensor also has binding sites on the outer surface of the cladding for binding to elements to be detected to the outer surface of the cladding. The cladding may be thinned down to a thickness sufficiently low produce the resonant wavelengths. The binding sites include agents for binding to the elements to be detected with the agents being covalently bonded to the surface of the cladding. Example binding sites can include bacteriophages for detecting E. coli bacteria, Palladium for detecting hydrogen, or synthetic DNA for detecting viruses of certain molecules for example.

Abstract: A fiber optic probe for capable of simultaneously enhancing fluorescent emission collection and reducing stray excitation light noise levels while detecting the presence or absence of one or more substances within a medium. The probe includes an illuminating optical fiber for guiding excitation light from a light source to be launched from an end face of the illuminating optical fiber. A film or an immersion medium emits light when illuminated by the excitation light. The emitted light has a central wavelength that is different than a central wavelength of the excitation light. A receiving optical fiber receives and guides the emitted light. The receiving fiber may be a photonic crystal fiber having an end portion which is a solid segment of glass for improved light collection efficiency. A lens may be provided at the end of the receiving fiber. A detector detects light from the receiving optical fiber.

Abstract: A fiber optic probe for detecting the presence or absence of one or more substances within a medium. The probe comprises at least one illuminating optical fiber for guiding excitation light from a light source to be launched from an end face of the illuminating optical fiber. A film or an immersion medium is provided for emitting light when illuminated by the excitation light. The emitted light has a central wavelength that is different than a central wavelength of the excitation light. At least one receiving optical fiber is provided to receive and guide the emitted light. The receiving fiber may be a photonic crystal fiber having an end portion which is a solid segment of glass for improved light collection efficiency. A lens may be provided at the end of the receiving fiber. Detection means are provided for detecting light from the receiving optical fiber.

Abstract: An apparatus and a method are provided for measuring an ambient physical parameter applied to a highly birefringent sensing fiber. A light source emits a low coherence light beam into a sensing fiber subjected to an ambient physical parameter. A collector receives the output light beam of the sensing fiber and a splitter divides the output light beam into two orthogonally polarized output beams and subjects the two orthogonally polarized output beams to a range of relative delays. A recombiner combines the two orthogonally polarized output beams to produce an interference pattern, and a detector detects intensities of the interference pattern over the range of delays. A calculating device determines the ambient parameter from the intensities with improved accuracy.

Abstract: A fiber-optic strain gauge manometer and a method thereof are for measuring pressure of a fluid, to be respectively connected to a light source and a measurement apparatus. The manometer comprises: a cylindrical hollow body, acting as a pressure transducer, having an inlet by which the fluid can get inside, free ends such that longitudinal and circumferential strains are generated in the hollow body by the pressure of the fluid, thereby producing a dilatation of the hollow body, and a highly birefringent optical fiber having a sensing portion bonded to the outer surface of the hollow body along a longitudinal path such that its birefringence changes when the sensing portion is subjected to the dilatation of the hollow body. A polarized light beam is generated by the light source and transmitted in a form of two polarization eigenstates each parallel to one of two parallel principal birefringence axes of the birefringent optical fiber.

Abstract: The method is for measurement of pressure applied to a sensing element comprising a cholesteric liquid crystal being connected to multimode optical fibers for communication with a light source and a device for measurement of light intensity. The method resides in guiding a light beam of predetermined wavelength generated by the light source toward a layer of the cholesteric liquid crystal using one of the multimode optical fibers. The light beam reflected by the layer is collected using another of the multimode optical fibers being connected to the device for measurement of light intensity. This device measures then the intensity of the reflected light beam, such that a value indicative of the pressure as a function of the measured intensity can be carried out. This method is particularly well adapted for measuring pressure up to 100 MPa with a good linear response and sensitivity for specific ranges of pressure useful in industrial applications.

Abstract: The present disclosure describes a birefringent optical fiber device for measuring of ambient pressure in a stabilized temperature environment, when connected respectively to a light source and a measuring apparatus. The device comprises a first device for receiving polarized light from the light source; a birefringent fiber being connected to the first device for receiving the polarized light which has light signal components polarized along two orthogonal polarization axes of the berefringent fiber, the berefringent optical fiber having a preselected length determined by a range of pressures to be measured; and a second device for receiving light signals emitted from the birefringent fiber, the light signals having elliptical polarization state characterized by major and minor axes, whereby cross-talk between the light signal components along the polarization axes being responsive to the ambient pressure in the environment.