An apparatus includes a multi-mode optical fiber having a selected plurality of optical propagating modes. The selected plurality may include only a proper subset of or may include all of the optical propagating modes of the multi-mode optical fiber. Each optical propagating mode of the selected plurality has a group velocity that varies over a corresponding range for light in, at least, one of the optical telecommunications C-band, the optical telecommunications L-band, and the optical telecommunications S-band. The ranges corresponding to different ones of the modes of the selected plurality are non-overlapping. The ranges of a group velocity-adjacent pair of the ranges are separated by a nonzero gap of less than about 10,000 meters per second.

An optical fiber includes: a first core portion capable of transmitting first light; a second core portion formed on an outer periphery of the first core portion in a structure different from that of the first core portion and capable of transmitting second light different from the first light. The second core portion is formed around the outer periphery of the first core portion, and a center of the second core portion is positioned in a region of the first core portion.

A system for testing an optical fiber includes an optical source apparatus and an optical image sensor apparatus. The optical source apparatus includes a fiber optic connector that connects to a first end of the fiber, and a light emitting device which emits light into the first end of the fiber. The optical image sensor apparatus includes a fiber optic connector that connects to a second end of the fiber, an image sensor that receives light output from the second end of the fiber and generates corresponding image data, a lens array in an optical path between the fiber optic connector and the image sensor, and a processor coupled to the image sensor. The processor, in operation, determines a set of two-dimensional positions based on the image data output from the image sensor, and determines a test result based on the set of two-dimensional positions.

A method of characterizing an optical system, wherein the optical system comprises an optical fibre having a proximal end and a distal end, wherein the optical fibre comprises a non-single-mode optical fibre, and comprising a reflector assembly comprising a stack of reflectors disposed at the distal end of the optical fibre, wherein the stack of reflectors is arranged to provide different reflector matrices in dependence on illumination wavelength. The method comprises projecting calibration patterns at a plurality of characterization wavelengths onto the proximal end, then obtaining, at the proximal end, data relating to reflected calibration patterns. An instantaneous transmission matrix of the optical fibre is then determined using the data relating to the reflected calibration patterns and the reflector matrices.

Provided are laser sources, the laser sources comprising at least one diode; and an optic fiber of a predefined length disposed between the laser source and a position for a target such that the optic fiber communicates light pulses from the laser source as a source light to the position for the target, wherein the position is illuminated by the source light so as to reduce speckles in a captured image of the target. Also provided are methods for providing source light for generating an image, comprising: generating illumination with one or more laser diodes; and passing the illumination through an optic fiber having a plurality of bends therein such that source light is emitted from the optic fiber so as to illuminate a target with the source light, the source light reducing speckles in an image of the target.

A class of fibers is described that have a non-circular cross section on one or both ends that can by optimized to capture the optical radiation from a laser diode or diode array and deliver the light in the same or different shape on the opposite end of the fiber. A large multimode rectangular waveguide may be provided which can accept the radiation from a high-power diode bar and transform it into a circular cross section on the opposite end, while preserving brightness.

Provided is a mode controller which includes an optical fiber coupled body and at least one pair of bobbins, and the mode controller is configured so that: the one pair of bobbins includes two bobbins arranged, spaced from one another; the optical fiber coupled body includes a step-index fiber and a graded-index fiber, which are coupled with each other; the step-index fiber and/or the graded-index fiber is/are wound around the at least one pair of bobbins, and twisted to form a helical area(s); light is launched into the step-index fiber, propagates through the step-index fiber, is emitted from the step-index fiber, and is launched into the graded-index fiber; propagation mode of the light is converted to an equilibrium mode distribution during the propagation of the light through the step-index fiber; and the propagation mode of the light launched into the graded-index fiber is converted to a low-order mode.

A laser processing apparatus includes a process laser light source, a first optical system, a pulse laser light source, a second optical system, and an optical detection portion. The process laser light source generates a process laser beam having a continuous energy density during a certain period of time. The first optical system directs the process laser beam to a surface of a workpiece. The pulse laser light source generates a pulse laser beam having an energy density with a peak value that is higher than the energy density of the process laser beam. The second optical system directs the pulse laser beam to a process portion of the workpiece. The optical detection portion detects plasma light produced at the process portion of the workpiece.

A fiber connected body includes: a first multi-core fiber including a first cladding, first cores disposed in the first cladding, and a first marker disposed in the first cladding; and a second multi-core fiber including a second cladding, second cores disposed in the second cladding, and a second marker disposed in the second cladding. One end surface of the second multi-core fiber is connected to one end surface of the first multi-core fiber. Each of the second cores is connected to any one of the first cores, or each of the first cores is connected to any one of the second cores.

Disclosed is an optical waveguide including a waveguide core and waveguide cladding surrounding the waveguide core. The waveguide cladding includes at least one stack of cladding material layers positioned laterally adjacent to a sidewall of the waveguide core such that each cladding material layer in the stack abuts the sidewall of the waveguide core. Each of the cladding material layers in the stack has a smaller refractive index than the waveguide core and at least two of the cladding material layers in the stack have different refractive indices, thereby tailoring field confinement and reshaping the optical mode. Different embodiments include different numbers of cladding material layers in the stack, different stacking orders of the cladding material layers, different waveguide core types, symmetric or asymmetric cladding structures on opposite sides of the waveguide core, etc. Also disclosed is a method of forming the optical waveguide.