Abstract: An optical instrument for light incoming along a principal optical axis includes a glass block and a subsurface object within the glass block. The subsurface object includes an arrangement of object marks. Each object mark includes a plurality of scattering layers stacked against the principal optical axis of the incoming light. First and second scattering layers of the plurality of scattering layers have different polarization responses.

Abstract: An optical instrument for light incoming along a principal optical axis includes a glass block and a subsurface object within the glass block. The subsurface object includes an arrangement of object marks. Each object mark includes a plurality of scattering layers stacked against the principal optical axis of the incoming light. First and second scattering layers of the plurality of scattering layers have different polarization responses.

Abstract: An optical instrument for light incoming along a principal optical axis includes a glass block and a subsurface object within the glass block. The subsurface object includes an arrangement of object marks. Each object mark includes a plurality of scattering layers stacked against the principal optical axis of the incoming light. First and second scattering layers of the plurality of scattering layers have different polarization responses.

Abstract: A laser includes a gain stage and a pump stage. The gain stage includes a fiber link that terminates at a pair of ends and includes a doped fiber. The pump stage includes a glass volume, the glass volume having a pair of fiber interface ports at which the pair of ends of the fiber link are disposed, respectively, for attachment of the gain stage and the pump stage in a ring laser assembly. The pump stage includes a plurality of intrinsic waveguides defined in the glass volume and disposed along in-bulk propagation paths within the glass volume for light travel through the ring laser assembly.

Abstract: A method continuously monitors variations in the size of particles present in a fluid on a real time basis. The method includes passing one or more optical signal through the fluid such as engine oil. The variation (attenuation or enhancement) in the intensity of the optical signal is continuously measured with respect to time. In an embodiment, the method enables monitoring of the amount, size and onset of particle agglomeration using single or multiple wavelengths as interrogating optical signal(s). An exemplary embodiment is provided for monitoring of the amount, size and onset of soot particle agglomeration in engine oil using single or multiple wavelengths as interrogating optical signal(s).

Abstract: A method of writing a waveguide using an ultrashort laser beam is disclosed. The laser beam is directed to a substrate in transverse relation to a waveguide propagation axis to generate an ultrashort laser pulse focus in the substrate. A refractive index is modified in an affected region in the substrate along the waveguide propagation axis via the ultrashort laser pulse focus, and the ultrashort laser pulse focus is moved in a direction other than the waveguide propagation axis to generate a widened affected region along the waveguide propagation axis. The widened affected region has a cross-sectional profile capable of supporting a fundamental mode of a signal having a telecommunications infrared (TIR) wavelength, while the affected region has a cross-sectional profile incapable of supporting the fundamental mode of the signal having the TIR wavelength.

Abstract: Disclosed herein are an optical device, such as a connector or mode enlarger, and a method of fabricating the device. The disclosed device includes an optical medium having a first face for, e.g., permanent attachment to a waveguide, a second face for, e.g., a non-permanent connection, and a region between the first and second faces. A non-fiber, connector waveguide is disposed in the region to propagate the single-mode signal from the first face to the second face. The connector waveguide is optically matched to the waveguide at the first face to receive the single-mode signal carried by the waveguide. The connector waveguide includes a taper section such that the connector waveguide is enlarged at the second face to support an expanded beam of the single-mode signal for propagation through the non-permanent connection.

Abstract: A method of writing a waveguide using an ultrashort laser beam is disclosed. The laser beam is directed to a substrate in transverse relation to a waveguide propagation axis to generate an ultrashort laser pulse focus in the substrate. A refractive index is modified in an affected region in the substrate along the waveguide propagation axis via the ultrashort laser pulse focus, and the ultrashort laser pulse focus is moved in a direction other than the waveguide propagation axis to generate a widened affected region along the waveguide propagation axis. The widened affected region has a cross-sectional profile capable of supporting a fundamental mode of a signal having a telecommunications infrared (TIR) wavelength, while the affected region has a cross-sectional profile incapable of supporting the fundamental mode of the signal having the TIR wavelength.

Abstract: Ultrafast pulse beams of light are used to direct-write three-dimensional index profiles in materials using the unique material changing capabilities of ultra-short (i.e. <10 picosecond) laser pulses. An existing waveguide or waveguide circuit fabricated by some technique (for example but not limited to photolithography, flame hydrolysis deposition, modified chemical vapor deposition, or ultra-fast laser pulse direct writing) is modified by altering the index of refraction (index trimming) in a localized region or different local regions of the waveguide structure. Index trimming is accomplished through the action of a focused laser beam (or multiple focused beams) consisting of one or more ultra-short laser pulses and is generally performed at a wavelength in which the material is transparent or weakly absorbing, to the fundamental wavelength of the beam of light. The trimmed index pattern is generated by, but not limited to, moving the focal position of the beam or by moving the sample (i.e.

Abstract: Ultrafast pulse beams of light are used to direct-write three-dimensional index profiles in materials using the unique material changing capabilities of ultra-short (i.e. <10 picosecond) laser pulses. An existing waveguide or waveguide circuit fabricated by some technique (for example but not limited to photolithography, flame hydrolysis deposition, modified chemical vapor deposition, or ultra-fast laser pulse direct writing) is modified by altering the index of refraction (index trimming) in a localized region or different local regions of the waveguide structure. Index trimming is accomplished through the action of a focused laser beam (or multiple focused beams) consisting of one or more ultra-short laser pulses and is generally performed at a wavelength in which the material is transparent or weakly absorbing, to the fundamental wavelength of the beam of light. The trimmed index pattern is generated by, but not limited to, moving the focal position of the beam or by moving the sample (i.e.