A beam combiner includes: a plurality of input optical fibers, a beam combination optical fiber and an output optical fiber; the input optical fiber includes an input fiber core and an optical fiber input cladding layer wrapping an outer wall of the input fiber core, the output optical fiber includes an output fiber core and an optical fiber output cladding layer wrapping an outer wall of the output fiber core, a cross section of the optical fiber input cladding layer is fan-shaped or hexagonal and is provided with a groove and/or a protrusion along an axial direction, the plurality of input optical fibers are nested with each other to form the beam combination optical fiber, fiber cores in the beam combination optical fiber are all connected to the output fiber core, and a beam combination cladding layer of the beam combination optical fiber is connected to the output fiber core.

A compounded light-focusing optical element is configured to focus light, and the compounded light-focusing optical element includes a body having a first, flat, end face and a second, curved end face, the second, curved end face being opposite to the first, flat end face, and plural optical fibers extending through the body, from the first, flat end face to the second, curved end face. The plural optical fibers are fused to each other to form the body, and end faces of the plural optical fibers, corresponding to the second, curved end face, are pointing in different directions.

A method of re-splicing a splice-on connector (“SOC”) includes at least five steps: (1) stripping insulation from an end portion of a first optic fiber; (2) stripping insulation from an end portion of a second optic fiber having a connector body fixed to an opposite end portion thereof. One end portion of the connector body is sized and configured to be inserted into an end portion of an elongated hollow member. The method also includes: (3) splicing together the first and second fiber optic end portions to produce either an SOC or a re-spliced splice-on connector (“RSSOC”). The SOC has a predetermined length to enable cutting at three predetermined locations spaced from the connector body. The method further includes: (4) if an operational fault is caused in a system using the SOC or RSSOC, cutting the SOC or the RSSOC at one of the three predetermined regions; and (5) repeating step (3).

The present invention relates to a fiber exit element (1), comprising: a plurality of glass fibers (10) each having at least one core (10a) which is designed to guide a signal light ray (A); and at least one optical element (14), preferably an optical window (14), an optical lens (14), an optical beam splitter (14) or an optical prism (14), which is connected to each open end (11) of the cores (10a) of the glass fibers (10) and is designed to receive the signal light ray (A) from the open ends (11) of the cores (10a) of the glass fibers (10) and to output said signal light ray to the outside via at least one exit face (14b) as exit rays (A′). The fiber exit element (1) is characterized in that the open ends (11) of the cores (10a) of the glass fibers (10), and preferably also the open ends (11) of claddings (10b) of the glass fibers (10) substantially enclosing the cores (10a), are each arranged within the material of the optical element (14) with a depth of penetration (W), preferably with respect to an incident face (14a) of the optical element (14), at least the material of the open ends (11) of the cores (10a) of the glass fibers (10), preferably also the material of the open ends (11) of the claddings (10b) of the glass fibers (10), being fused to the material of the optical element (14).

Provided is an optical fiber coupler capable of suppressing variation of polarization state of light passing through a coupler portion. The optical fiber coupler includes: a substrate having a groove; a coupler portion which is inserted into the groove and to which a middle portion of each of optical fibers is joined; and an adhesive for bonding the coupler portion to the substrate. Shore D hardness of the adhesive is 10 to 35. By setting the Shore D hardness of the adhesive to 10 to 35, it is possible to suppress the variation of the polarization state of the light passing through the coupler portion.

There is described a multi-clad optical fiber for propagating an optical signal having at least a single mode. The multi-clad optical fiber generally has a fiber core, an inner cladding surrounding the fiber core, and at least an outer cladding surrounding the inner cladding, the multi-clad optical fiber having at least a taper portion extending along a longitudinal dimension z, the taper portion having a radial dimension progressively decreasing at a normalized slope exceeding an adiabaticity criterion of a conventional single-clad optical fiber propagating at least the single-mode across its single-mode core.

A laser device includes: a laser unit that outputs laser light; an output end that launches the laser light; a first fusion splice portion; and a second fusion splice portion. In each of the first fusion splice portion and the second fusion splice portion, two multi-mode fibers are fusion-spliced. Each of the two multi-mode fibers include a core through which the laser light propagates and a cladding that surrounds the core. The first fusion splice portion is disposed closer to the laser unit than is the second fusion splice portion. At least a part of the core in the first fusion splice portion contains a dopant that is the same type as a dopant contained in the cladding in the first fusion splice portion for decreasing a refractive index.

A fiber module (1B) according to the present disclosure includes an input-side optical fiber (11), an output-side optical fiber (12), a ferrule (20) in which the input-side optical fiber and the output-side optical fiber are insertable in both ends and a groove (32) is formed in a direction orthogonal to a longitudinal direction (D1) in the middle of the longitudinal direction, a dielectric multilayer film filter (30) inserted in the groove, and an input-side GI fiber (15) and an output-side GI fiber (16) joined by fusion to respective terminal portions of the input-side optical fiber and the output-side optical fiber. The dielectric multilayer film filter is interposed between an end surface (15f) of the input-side GI fiber and an end surface (16f) of the output-side GI fiber in the longitudinal direction.

A method for fixing a single-mode fiber to a multimode fiber comprises the following steps: injecting light radiation into the injection end of the single-mode fiber and positioning the junction ends of the single-mode fiber and of the multimode fiber relative to one another so as to propagate at least part of the light radiation in the multimode fiber; modally decomposing the light radiation collected at the injection end of the multimode fiber and measuring a quantity representative of the optical power present in a first group of secondary modes; and adjusting the relative position of the junction ends and freezing them with respect to one another in a determined relative coupling position. Coupling equipment for carrying out the fixing method is also disclosed.

The present invention therefore provides a method of splicing optical fibers. First, a first optical fiber and a second optical fiber are provided, wherein a core diameter of the first optical fiber is smaller than a core diameter of the second optical fiber. After performing a hydrogen loading treatment for the first optical fiber; a thermal expansion core (TEC) treatment is performed for the first optical fiber and the second optical fiber to match the mode-field (MF) of the first optical fiber and the second optical fiber at the fused section between the first optical fiber and the second optical fiber. The present invention further provides a spliced optical fiber, including a first optical fiber part, a second optical fiber part, and a fused section.