An optical fiber cable with one or more coil elements is provided. The optical fiber cable (200, 300, 400) comprises one or more optical transmission elements (202, 302, 402) extending in a longitudinal direction surrounded by one or more coil elements (100). The one or more coil elements are a series of loops such that each loop (106) from the series of loops is physically connected to adjacent loops. The one or more coil elements are flexible in transverse direction and are substantially non-elongatable in the longitudinal direction. The one or more coil elements are fiber retaining element (102) such that subsequent loops (106) are made of a single continuous element and further comprises a pitch retaining element (104) connecting the subsequent loops of the fiber retaining element to preserve relative position of the subsequent loops.

A multi-core/single-core conversion module is disclosed. The multi-core/single-core conversion module includes a housing including a first end, a second end and a lateral wall defining an inner space between the first end and the second end, a first adapter attached to the first end of the housing, two or more second adapters attached to the second end of the housing, a multi-core optical connector inserted into the first adapter from the inner space of the housing, a plurality of single-core optical connectors respectively inserted into the second adapters from the inner space of the housing, and a plurality of optical fibers connecting the multi-core optical connector to the plurality of single-core optical connectors with each other. The second adapters are arranged on the second end across a plurality of tiers. An opening can be formed by a part of the lateral wall being detached.

Disclosed is a Chinese knot-like porous fiber core ultra-high birefringence THz optical fiber. The optical fiber comprises a substrate, claddings and fiber cores, wherein the claddings and the fiber cores are arranged in the substrate, and the fiber cores are embedded in the centers of the claddings; and the fiber core comprises a first fiber core region, a second fiber core region and a third fiber core region, the center of the first fiber core region 4 serves as the origin of coordinates, and the first fiber core region 4 is composed of six regular hexagon units with overlapped boundaries in the x-axis direction. In the present disclosure, the fiber core comprises a first fiber core region, a second fiber core region and a third fiber core region, and the three regions jointly form a fiber core region of a Chinese knot-like porous fiber core.

An optical probe imaging system includes an optical probe having a multicore optical fiber. Distal optics image light propagating in the multicore optical fiber so as to generate a light pattern on a sample that is based on a relative position of the cores. A distal motor causes the light pattern to traverse a path across the sample. An optical receiver includes a first receiver receiving light that has traversed the path across the sample from one of the at least two cores and a second receiver receiving light that has traversed the path across the sample from the other of the cores, such that the first receiver and the second receiver detect light in parallel. A processor maps relative position of the cores at the distal facet based on signals generated by the receiver.

The present embodiment relates to an MCF having a low transmission loss and having a structure for reducing a transmission loss and effectively suppressing an inter-core XT. The uncoupled MCF includes alkali metal having a predetermined concentration in which each of a plurality of cores contributes to reduction in the transmission loss, and a core pitch is set so that a sum h_.sub.total of power coupling coefficients of a specific core and the remaining all cores of the plurality of cores is 2.3×10.sup.−4/km or less.

There is described an optical fiber coupler generally having: a first optical fiber having a longitudinally extending multimode guiding region and a first taper portion longitudinally extending between first and second locations of the first optical fiber, the first taper portion having a dimension progressively decreasing along a first taper direction from the first location to the second location; a second optical fiber having a longitudinally extending multimode guiding region and a second taper portion longitudinally extending between third and fourth locations of the second optical fiber, the second taper portion having a dimension progressively decreasing along a second taper direction from the third location to the fourth location; and a coupling region where at least a portion of the first taper portion is optically coupled to a portion of the second taper portion, with the first and second taper directions being opposite to one another.

An apparatus is includes a near field transducer positioned adjacent a media-facing surface and at the end of a waveguide having at least one core layer and a cladding layer. The apparatus also includes at least one optical reflector positioned adjacent opposing cross-track edges of the near field transducer and/or adjacent a down-track side of the near-field transducer.

A proximity sensor includes a light source configured to emit a beam of optical radiation and a detector configured to output an electrical signal in response to the optical radiation that is incident on the detector. A first optical multimode fiber is configured to receive the emitted beam and to direct the emitted beam toward an object. A second optical multimode fiber is configured to receive the optical radiation reflected from the object and to convey the received optical radiation to the detector. A processor is coupled to process the electrical signal so as to compute a distance to the object.

The MCF of the present disclosure suppresses XT and leakage loss at 1.565 μm or 1.625 μm for bidirectional communication. The MCF comprises 12 core units each including a core and a depressed layer, a common cladding, and a resin coating. The units are arranged so that no adjacent relationship is established between cores each having an adjacent relationship with a specific core selected from the units, and are arranged so that centers of the units are line symmetric with a symmetry axis intersecting with the central axis and passing through none of the centers of the units. The resin coating's diameter is 250±15 μm, an effective area at 1.550 μm is 70 μm.sup.2 or more, and a 22 m-length cable cutoff wavelength is 1.530 μm or less. A center-to-center interval between adjacent cores, a shortest distance from the core center to the cladding interface, and a cladding's diameter satisfy specific conditions.

A measurement system for assisting in guiding an elongated medical device in a body is described. The measurement system comprises a multicore fiber for insertion into an elongated medical device such that a position of the tip of the multicore fiber corresponds with a position near the tip of the elongated medical device, the multicore fiber comprising a plurality of cores, and a measurement device being adapted for determining, based on the optical signals measured from the multicore fiber, a known shape applied to the multicore fiber, and for deriving based thereon, a length of the portion of the multicore fiber that has been introduced in the body or a position of the multicore fiber in the body.