An optical fiber (F2) having a length defining a longitudinal direction is disclosed. The optical fiber (F2) has at least two fiber cores (C21, C22) extending along the length of the optical fiber (F2), and an optical coupling member (OCM2) is arranged at a proximal optical fiber end of the optical fiber (F2). The coupling member (OCM2) has a first distal end face (OF2) optically connected to the proximal optical fiber end, and a proximal second end face (IF2) spaced apart from the first distal end face (OF2) in the longitudinal direction of the optical fiber (F2), the optical coupling member (OCM2) being configured to couple light into each of the fiber cores (C21, C22, C23).

A system for positioning an optical preform in a furnace is provided that includes an upper muffle and a downfeed handle assembly with a tube defining a first end and a second end, the second end extending into the upper muffle. A handle is disposed within the tube. A second end of the handle extends into the upper muffle and a seal assembly is positioned around both the tube and the handle. The first end of the handle extends through the seal assembly and a drive assembly is coupled with the downfeed handle.

A fiber structure includes a covering part, the covering part having an optical fiber strand and a coating covering the optical fiber strand; a strand exposed part adjacent to the covering part, the strand exposed part including an exposed optical fiber strand, and a sealing part covering a boundary between the covering part and the strand exposed part. The sealing part including a fluororesin having a structure represented by formula (1):

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where R represents a divalent organic fluorine compound group, and n represents an integer of 1 or more.

Arrays of fiber pigtails can be used to project and receive light. Unfortunately, most fiber pigtail arrays are not aligned well enough for coherently combining different optical beams. This imprecision stems in part from misalignment between the optical fiber and the endcap spliced to the end of the optical fiber. The endcap is often polished, curved, or patterned, causing the light emitted by the endcapped fiber to refract or diffract as it exits the endcap. This refraction or diffraction shifts the apparent position of the beam waist from its actual position. Measuring this virtual beam waist position before and after splicing the endcap to the fiber increases the absolute precision with which the fiber is aligned to the endcap. This increase in absolute precision reduces the deviation in virtual beam waist position among endcapped fibers, making it easier to produce arrays of endcapped fibers aligned precisely enough for coherent beam combining.

The present invention provides a receptacle structure for an optical connector comprising a receptacle body, and a first housing. The receptacle body has a first end and a second end for providing optical connector inserted thereto, respectively. Two sides of the first end respectively have first flexible plate having first attaching structure. The first housing, folded by a single piece material, is a closed structure having a first through hole wherein two walls of the first housing have first coupling structure for coupling to the attaching structure when the first end of the receptacle body is inserted into the first through hole whereby the first housing is completely assembled with the receptacle body. In addition, an optical communication device having the receptacle structure is also provided in which the optical connector can be inserted into the receptacle structure for optical communication.

An optical fiber fuse protection device includes an upstream optical fiber disposed on an upstream side, a downstream optical fiber disposed on a downstream side, and a wall interposed between a part of the upstream optical fiber and a part of the downstream optical fiber. The downstream optical fiber is fusion-spliced to the upstream optical fiber and is made of a single optical fiber or a plurality of optical fibers fusion-spliced to each other.

An indexing terminal arrangement includes a terminal housing that receives an input cable; an optical power splitter disposed within the interior of the terminal housing; a first multi-fiber optical adapter coupled to the terminal housing; a first single-fiber optical adapter coupled to the terminal housing; and a pass-through multi-fiber optical adapter coupled to the terminal housing. Split optical signals are provided to the first multi-fiber optical adapter and the first single-fiber optical adapter. Unsplit and indexed optical signals are provided to the pass-through optical adapter.

An optical fiber line of one embodiment comprises an HNLF, an SMF, and an MFD transition portion. The MFD transition portion includes end portions of both the HNLF and the SMF facing with a fusion point thereof, and is a section in which an MFD changes such that a difference between a maximum value and a minimum value is 0.3 μm or more for a 100 μm-length. A splicing loss of the HNLF and the SMF at 1,550 nm is one-fifth or less than an ideal butting loss at stationary portions thereof. A total length of the MFD transition portion is 10 mm or less. In a region between one end surface of the HNLF at the fusion point and the other end surface separated from the one end surface by 50 μm or more and 300 μm or less, the MFD increases monotonically from the other end surface to the one end surface.

An optical fiber line of one embodiment comprises an HNLF, an SMF, and an MFD transition portion. The MFD transition portion includes end portions of both the HNLF and the SMF facing with a fusion point thereof, and is a section in which an MFD changes such that a difference between a maximum value and a minimum value is 0.3 μm or more for a 100 μm-length. A splicing loss of the HNLF and the SMF at 1,550 nm is one-fifth or less than an ideal butting loss at stationary portions thereof. A total length of the MFD transition portion is 10 mm or less. In a region between one end surface of the HNLF at the fusion point and the other end surface separated from the one end surface by 50 μm or more and 300 μm or less, the MFD increases monotonically from the other end surface to the one end surface.

The technology of this application relates to an optical component constituting a fiber amplifier, a fiber amplifier, and a manufacturing method. The optical component is connected to a gain fiber by using a first fiber, or the optical component is directly connected to the gain fiber. The optical component is connected to one or more second optical components in the fiber amplifier by using a second fiber, and/or the optical component inputs an optical signal or outputs an optical signal amplified by the gain fiber by using the second fiber. Softening temperatures and/or refractive indexes of the first fiber and the second fiber are different, or softening temperatures and/or refractive indexes of the second fiber and the gain fiber are different.