Abstract: An optical probe includes an optical source that generates an optical beam that propagates from a proximal end to a distal end of an optical fiber that imparts a transformation of a spatial profile of the optical beam. An optical control device imparts a compensating spatial profile on the optical beam that at least partially compensates for the transformation of the spatial profile of the optical beam imparted by the optical fiber in response to a control signal from a signal processor. A distal optical source generates a calibration light that propagates through the one or more optical waveguides from the distal end to the proximal end of the optical fiber. An optical detector detects the calibration light and generates electrical signals in response to the detected calibration light.

Abstract: An optical probe includes an optical source that generates an optical beam that propagates from a proximal end to a distal end of an optical fiber that imparts a transformation of a spatial profile of the optical beam. An optical control device imparts a compensating spatial profile on the optical beam that at least partially compensates for the transformation of the spatial profile of the optical beam imparted by the optical fiber in response to a control signal from a signal processor. A distal optical source generates a calibration light that propagates through the one or more optical waveguides from the distal end to the proximal end of the optical fiber. An optical detector detects the calibration light and generates electrical signals in response to the detected calibration light.

Abstract: An optical probe includes an optical source that generates an optical beam that propagates from a proximal end to a distal end of an optical fiber that imparts a transformation of a spatial profile of the optical beam. An optical control device imparts a compensating spatial profile on the optical beam that at least partially compensates for the transformation of the spatial profile of the optical beam imparted by the optical fiber in response to a control signal from a signal processor. A distal optical source generates a calibration light that propagates through the one or more optical waveguides from the distal end to the proximal end of the optical fiber. An optical detector detects the calibration light and generates electrical signals in response to the detected calibration light.

Abstract: A hollow core fiber (HCF) has a cross section with a substantially-circular hollow core in a cladding lattice, an axial center and a reference direction that extends radially in one direction from the axial center. The HCF comprises modified holes that are located along linear paths that extend radially outward from the axial center. The modified holes, which are located at various radial distances from the axial center and at various azimuthal angles from the reference direction, have non-uniform modified properties. These non-uniform modified properties include radially-varying properties, azimuthally-varying properties, or a combination of radially-varying and azimuthally-varying properties.

Abstract: A high backscattering fiber comprising a perturbed segment in which the perturbed segment reflects a relative power that is more than three (3) decibels (dB) above Rayleigh scattering. The high backscattering fiber also exhibits a coupling loss of less than 0.5 dB.

Abstract: A high backscattering fiber comprising a perturbed segment in which the perturbed segment reflects a relative power that is more than three (3) decibels (dB) above Rayleigh scattering. The high backscattering fiber also exhibits a coupling loss of less than 0.5 dB.

Abstract: A high backscattering fiber comprising a perturbed segment in which the perturbed segment reflects a relative power that is more than three (3) decibels (dB) above Rayleigh scattering. The high backscattering fiber also exhibits a coupling loss of less than 0.5 dB.

Abstract: A method of, and apparatus for, inscribing a grating in an optical waveguide so as to reduce transverse inscription variations, are provided. The waveguide is exposed to multiple beams or interference patterns of actinic radiation from multiple azimuthal directions. The beams of actinic radiation are preferably split into a plurality of beams that have wave vectors with different longitudinal components, e.g., via gratings such as phase masks. The periods and phases of the interference patterns of the beams of actinic radiation are preferably matched. A control beam may be provided that does not hit the waveguide. A control loop optionally controls at least one of the position or orientation of at least one of the beams of actinic radiation. The gratings are, for example, Bragg gratings.

Abstract: A multicore fiber alignment apparatus is described, having a chassis into which is mounted ferrule-holding means for holding a multicore fiber ferrule having one or more capillaries extending therethrough. Fiber-holding means for holding one or more multicore fibers in position to be mounted into the ferrule, such that each multicore fiber extends through a respective ferrule capillary. Means are provided for monitoring the rotation angle of each multicore fiber within its respective capillary, relative to a reference rotational orientation. Means are further provided for rotating each of the multicore fibers within its respective capillary. The rotational orientation of each multicore fiber is fixed when its rotation angle is equal to zero.

Abstract: A high backscattering fiber comprising a perturbed segment in which the perturbed segment reflects a relative power that is more than three (3) decibels (dB) above Rayleigh scattering. The high backscattering fiber also exhibits a coupling loss of less than 0.5 dB.

Abstract: A multicore fiber alignment apparatus is described, having a chassis into which is mounted ferrule-holding means for holding a multicore fiber ferrule having one or more capillaries extending therethrough. Fiber-holding means for holding one or more multicore fibers in position to be mounted into the ferrule, such that each multicore fiber extends through a respective ferrule capillary. Means are provided for monitoring the rotation angle of each multicore fiber within its respective capillary, relative to a reference rotational orientation. Means are further provided for rotating each of the multicore fibers within its respective capillary. The rotational orientation of each multicore fiber is fixed when its rotation angle is equal to zero.

Abstract: A multicore fiber alignment apparatus is described, having a chassis into which is mounted ferrule-holding means for holding a multicore fiber ferrule having one or more capillaries extending therethrough. Fiber-holding means for holding one or more multicore fibers in position to be mounted into the ferrule, such that each multicore fiber extends through a respective ferrule capillary. Means are provided for monitoring the rotation angle of each multicore fiber within its respective capillary, relative to a reference rotational orientation. Means are further provided for rotating each of the multicore fibers within its respective capillary. The rotational orientation of each multicore fiber is fixed when its rotation angle is equal to zero.

Abstract: A Raman distributed feedback (DFB) fiber laser is disclosed. It includes a pump source and a Raman gain fiber of a length smaller than 20 cm containing a distributed feedback (DFB) grating with a discrete phase structure located within no more than 10% off the center of the grating and wherein the Raman DFB fiber laser generates a laser signal with an optical spectrum, which has an optical bandwidth at half maximum optical intensity of less than 1 gigahertz (GHz) (wherein a maximum intensity frequency is different from the frequency of the pump laser). The Raman laser includes compensation for the nonlinear phase change due to Kerr effect and thermal effect resulting from absorption of the optical field, thus enhancing the conversion efficiency.

Abstract: A multicore fiber alignment apparatus is described, having a chassis into which is mounted ferrule-holding means for holding a multicore fiber ferrule having one or more capillaries extending therethrough. Fiber-holding means for holding one or more multicore fibers in position to be mounted into the ferrule, such that each multicore fiber extends through a respective ferrule capillary. Means are provided for monitoring the rotation angle of each multicore fiber within its respective capillary, relative to a reference rotational orientation. Means are further provided for rotating each of the multicore fibers within its respective capillary. The rotational orientation of each multicore fiber is fixed when its rotation angle is equal to zero.

Abstract: A method of, and apparatus for, inscribing a grating in an optical waveguide so as to reduce transverse inscription variations, are provided. The waveguide is exposed to multiple beams or interference patterns of actinic radiation from multiple azimuthal directions. The beams of actinic radiation are preferably split into a plurality of beams that have wave vectors with different longitudinal components, e.g., via gratings such as phase masks. The periods and phases of the interference patterns of the beams of actinic radiation are preferably matched. A control beam may be provided that does not hit the waveguide. A control loop optionally controls at least one of the position or orientation of at least one of the beams of actinic radiation. The gratings are, for example, Bragg gratings.

Abstract: A Raman distributed feedback (DFB) fiber laser is disclosed. It includes a pump source and a Raman gain fiber of a length smaller than 20 cm containing a distributed feedback (DFB) grating with a discrete phase structure located within no more than 10% off the center of the grating and wherein the Raman DFB fiber laser generates a laser signal with an optical spectrum, which has an optical bandwidth at half maximum optical intensity of less than 1 gigahertz (GHz) (wherein a maximum intensity frequency is different from the frequency of the pump laser). The Raman laser includes compensation for the nonlinear phase change due to Kerr effect and thermal effect resulting from absorption of the optical field, thus enhancing the conversion efficiency.