Abstract: A laser system based on nonlinear pulse compression and a LMA optical fiber therefor are provided. The LMA optical fiber is configured to amplify seed light pulses and promote the onset of nonlinear spectral broadening. The LMA optical fiber includes a first section having constant core and cladding diameters and receiving and supporting propagation of the light pulses in multiple transversal modes. The first section is configured to suppress high order modes propagating therealong. The LMA optical fiber further includes a tapered second section receiving the fundamental mode from the first section, the core and cladding diameters increasing gradually along said second section so as to provide an adiabatic transition of the fundamental mode. The LMA optical fiber further includes an optional third section having constant core and cladding diameters. Dispersive compression of the light pulses outputted by the LMA optical fiber provides excellent beam quality and high peak powers.

Abstract: A laser system based on nonlinear pulse compression and a LMA optical fiber therefor are provided. The LMA optical fiber is configured to amplify seed light pulses and promote the onset of nonlinear spectral broadening. The LMA optical fiber includes a first section having constant core and cladding diameters and receiving and supporting propagation of the light pulses in multiple transversal modes. The first section is configured to suppress high order modes propagating therealong. The LMA optical fiber further includes a tapered second section receiving the fundamental mode from the first section, the core and cladding diameters increasing gradually along said second section so as to provide an adiabatic transition of the fundamental mode. The LMA optical fiber further includes an optional third section having constant core and cladding diameters. Dispersive compression of the light pulses outputted by the LMA optical fiber provides excellent beam quality and high peak powers.

Abstract: A multicore optical fiber includes a cladding and multiple cores disposed in the cladding. Each core has a light-guiding path and follows a helical trajectory about a fiber axis. The multicore fiber also includes a set of discrete lateral coupling zones, which are longitudinally distributed and azimuthally aligned with respect to the fiber axis. Each lateral coupling zone forms an optical coupling path, which enables at least one of lateral in-coupling and out-coupling of light between a corresponding one of the cores and an exterior of the multicore fiber. An optical probing system for light delivery to and/or light collection from a probed region includes a multicore optical fiber to enable coupling of guided light out of the cores for delivery to the probed region and/or collection of light from the probed region for coupling into one of the cores.

Abstract: A multicore optical fiber includes a cladding and multiple cores disposed in the cladding. Each core has a light-guiding path and follows a helical trajectory about a fiber axis. The multicore fiber also includes a set of discrete lateral coupling zones, which are longitudinally distributed and azimuthally aligned with respect to the fiber axis. Each lateral coupling zone forms an optical coupling path, which enables at least one of lateral in-coupling and out-coupling of light between a corresponding one of the cores and an exterior of the multicore fiber. An optical probing system for light delivery to and/or light collection from a probed region includes a multicore optical fiber to enable coupling of guided light out of the cores for delivery to the probed region and/or collection of light from the probed region for coupling into one of the cores.

Abstract: An optical module for use in a motion responsive system includes a support and a proof mass mechanically coupled and displaceable relative to the support along at least one sensing axis in response to a motion experienced by the support. The module also includes an optical monitoring assembly for monitoring the proof mass with an optical beam impinging on the proof mass, the beam including a plurality of dedicated spectral components. The module further includes an optical spectral filter including a plurality of filtering regions, each being associated with a corresponding dedicated spectral component and having a spectral profile including a distinct dedicated filtering band encompassing the spectral component, such that a displacement of the proof mass along the at least one sensing axis produces, after filtering of the beam, a change in optical power of the spectral components indicative of the motion experienced by the support.

Abstract: Optical fiber assemblies for filtering of higher-order modes include a winding support and an optical fiber wound along a winding path on the winding support. The optical fiber is configured to support a fundamental transverse mode and one or more higher-order transverse modes. The optical fiber has a longitudinal fiber axis, a core, a cladding surrounding the core, a transverse cross-section lacking circular symmetry, and a rotation imparted thereto about the longitudinal fiber axis. The rotation and winding of the optical fiber provide stronger attenuation of the one or more higher-order transverse modes as compared to the fundamental transverse mode. In some implementations, the winding path has a non-constant radius of curvature. In other implementations, the optical fiber has a diameter larger than 10 micrometers and at least one stress-applying part arranged in the cladding about the core. Methods perform higher-order-mode filtering.

Abstract: optical module for use in a motion responsive system includes a support and a proof mass mechanically coupled and displaceable relative to the support along at least one sensing axis in response to a motion experienced by the support. The module also includes an optical monitoring assembly for monitoring the proof mass with an optical beam impinging on the proof mass, the beam including a plurality of dedicated spectral components. The module further includes an optical spectral filter including a plurality of filtering regions, each being associated with a corresponding dedicated spectral component and having a spectral profile including a distinct dedicated filtering band encompassing the spectral component, such that a displacement of the proof mass along the at least one sensing axis produces, after filtering of the beam, a change in optical power of the spectral components indicative of the motion experienced by the support.

Abstract: An optical fiber for use in a Coherent Anti-Stokes Raman Scattering (CARS) endoscope, comprising a core guiding lightwaves at a pump wavelength and at a Stokes wavelength, the core being single-mode at both wavelengths. The core is surrounded by cladding layers, including an inner cladding layer, a trench cladding layer, an intermediate cladding layer and an outer cladding layer. The refractive index of the trench cladding layer is lower than those of both neighboring cladding layers so as to define a trench in the radial refractive-index profile. The bending losses of the fundamental LP01 mode of the fiber at the Stokes wavelength are limited while maintaining high confinement losses for the higher-order LP11 mode of the fiber at the pump wavelength. The combination of the intermediate and outer cladding layers forms a multimode waveguide for guiding a collected CARS signal generated by an object or medium probed with the endoscope.

Abstract: An optical fiber for use in a Coherent Anti-Stokes Raman Scattering (CARS) endoscope, comprising a core guiding lightwaves at a pump wavelength and at a Stokes wavelength, the core being single-mode at both wavelengths. The core is surrounded by cladding layers, including an inner cladding layer, a trench cladding layer, an intermediate cladding layer and an outer cladding layer. The refractive index of the trench cladding layer is lower than those of both neighboring cladding layers so as to define a trench in the radial refractive-index profile. The bending losses of the fundamental LP01 mode of the fiber at the Stokes wavelength are limited while maintaining high confinement losses for the higher-order LP11 mode of the fiber at the pump wavelength. The combination of the intermediate and outer cladding layers forms a multimode waveguide for guiding a collected CARS signal generated by an object or medium probed with the endoscope.

Abstract: An optical fiber polarimetric chemical sensor for capillary gas chromatography in which a sample fluid is injected into a capillary in the form of a periodic pulse train. Each individual pulse defines a moving polarization coupling zone that affects the polarization state of the light propagating in a birefringent optical waveguide that includes the capillary. The spacing between consecutive coupling zones can be made equal to the polarization beat length of the waveguide when the injection frequency of the pulses is properly selected, thus defining a resonance condition for a given analyte. The contributions of the successive coupling zones present along the length of the capillary then add up in phase, thus resulting in a detected optical signal having an enhanced amplitude peak at the injection frequency. In this manner, the sensitivity can be enhanced.

Abstract: The invention relates to distributed optical waveguide polarimetric chemical analysis. Real-time monitoring of a separation process of a fluid in a capillary column is provided using a distributed sensor comprising a birefringent optical waveguide placed between two polarizers. The optical waveguide has a longitudinal channel defined by a channel surface in its cladding and adapted to receive the fluid such that it travels in said longitudinal channel. The longitudinal channel is positioned with respect to the core such that channel surface absorption of the fluid traveling in the longitudinal channel causes a local variation of the orientation of the polarization axes of the optical waveguide. The proposed embodiment can be used for monitoring the velocity of the separated components along the channel.