Method for adapting a fiber beam combiner to transmit at least 20 kW of optical power without noticeable bulk material damage mechanism effect and destructive nonlinearities, the method comprising: connecting an adiabatic beam combiner with a splice connection to an input facet of a graded index fiber which has a core doped with an index increasing material, further comprising the step(s) of: restricting the numerical aperture of the graded index fiber, and/or selecting the index increasing material with a Raman gain lower than that of Ge0.sub.2 such as Al2O3 or Y2O3, and/or placing a shroud tube around the graded index fiber core, said shroud tube comprising a fluorine-doped silica tube.

A fiber coupler is provided, which includes a tubular enveloping structure and several optical fibers arranged in the enveloping structure, each of which has a fiber core and a fiber cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fiber core to the diameter of the fiber cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fiber to the diameter of the fiber core, increases in the first direction for each optical fiber.

An apparatus for combining optical radiation, wherein the apparatus comprises a bundle of input optical fibres formed of glass, a taper, and an output optical fibre, wherein the taper is fused to the output optical fibre; and the apparatus comprises at least one cladding mode stripper to strip out higher order modes that would otherwise degrade a polymer coating on at least one of the input optical fibres and the output optical fibre.

A fiber coupler is provided, which includes a tubular enveloping structure and several optical fibers arranged in the enveloping structure, each of which has a fiber core and a fiber cladding surrounding same, in order to conduct laser radiation, and each of which extends from the first as far as the second end of the enveloping structure. The enveloping structure includes a tapering section which is tapered in a first direction from the first as far as the second end. In the tapering section, both a first ratio of the diameter of the fiber core to the diameter of the fiber cladding and also a second ratio of the diameter of the mode field of the laser radiation conducted in the optical fiber to the diameter of the fiber core, increases in the first direction for each optical fiber.

Multimode beam combiners include at least one gradient-step index optical fiber in which a refractive index difference at a core/cladding interface is selected to provide a numerical aperture so as to provide stable, uniform beam output. One or more such fibers is formed into a tapered bundle than can be shaped to provide a selected illuminated aperture. The fibers in the bundle can be separated by respective tapered claddings so as to be optically coupled or uncoupled. Illumination systems can include a plurality of such fibers coupled to a plurality of laser diodes or other light sources.

A laser component includes a pump-signal combiner, which includes a first capillary, a plurality of pump fibers, a second capillary, and a signal fiber. The plurality of pump fibers, the second capillary, and the signal fiber are arranged in a bundle configuration. The bundle configuration is disposed within an internal portion of the first capillary. A cross-section of the bundle configuration includes an outer area, in which the plurality of pump fibers are disposed, and an inner area, in which the second capillary and the signal fiber are disposed. The signal fiber is disposed within an internal portion of the second capillary.

Apparatus for laser processing a material (29), which apparatus comprises at least one first laser (15), at least one second laser (16), an optical combiner (3), and a multicore fibre (10), wherein: each first laser (15) is connected to the optical combiner (3) via a first feed fibre (1); each second laser (16) is connected to the optical combiner (3) via a second feed fibre (2); the optical combiner (3) connects the first feed fibre (1) to a first core (11) of the multicore fibre (10), and the second feed fibre (2) to a second core (12) of the multicore fibre (10); the optical combiner (3) provides a first optical path (41) from the first laser (15) to the first core (11) of the multicore fibre (10); the optical combiner (3) provides a second optical path (42) from the second laser (16) to the second core (12) of the multicore fibre (10); and the optical combiner (3) comprises a fibre bundle (4) that is tapered along its length.

A capillary combiner housing for an optical fiber combiner has an inner combiner casing supporting optical fibers. The capillary combiner housing includes a non-metallic body defining a lumen between an input side and an output side, the lumen sized to receive the inner combiner casing, the non-metallic body having a coefficient of thermal expansion substantially matching that of the inner combiner casing. Also included is a first aperture in the input side, the first aperture having a first inside diameter sized to receive multiple input optical fibers, and a second aperture in the output side, the second aperture having a second inside diameter sized to receive an output fiber.

A quantum communications device element comprising: a receiver configured to: receive a quantum input signal in a statistical mixture comprising a pre-determined set of quantum states; probabilistically determine the quantum states of the predetermined set of quantum states of the quantum input signal; and output input signals corresponding to the quantum states of the quantum input signal; a coupling device coupled to the receiver, said coupling device being configured to convert the input signals to an output signal by time-division multiplexing the input signals; and a detector coupled to the coupling device, the detector being configured to receive the output signal.

Provided a light modulating device including a variable mirror including a plurality of lattice structures, the plurality of lattice structures including a material having a refractive index that changes based on a temperature of the material, a distributed Bragg mirror spaced apart from the variable mirror and provided above the variable mirror, the distributed Bragg mirror including a first material layer and a second material layer that are alternately stacked, and a refractive index of the first material layer being different from a refractive index of the second material layer, and a heating portion configured to heat the plurality of lattice structures and provided below the variable mirror opposite to the distributed Bragg mirror.