A high backscattering optical fiber comprising a perturbed segment in which the perturbed segment reflects a relative power such that the optical fiber has an effective index of n.sub.eff, a numerical aperture of NA, a scatter of R.sub.p.fwdarw.r.sup.(fiber) that varies axially along the optical fiber, a total transmission loss of α.sub.fiber, an in-band range greater than one nanometer (1 nm), and a figure of merit (FOM) in the in-band range. The FOM being defined as:

[00001]$FOM=\frac{R_{p.fwdarw.r}^{\left(\mathrm{fiber}\right)}}{{{\alpha }_{\mathrm{fiber}}\left(\frac{\mathrm{NA}}{2n_{\mathrm{eff}}}\right)}^2}.$

A temperature monitoring apparatus configured to monitor a temperature of a portion of a vehicle's electrical energy distribution network is disclosed. The apparatus includes a first optical fibre including one or more temperature sensing sections, each temperature sensing section being for thermal contact with a portion of a vehicle's electrical energy distribution network. Each temperature sensing section is arranged to produce, in response to an optical input signal, an optical output signal indicative of the temperature of the temperature sensing section. The apparatus is arranged to determine a temperature of the portion of the vehicle's electrical energy distribution network based on one or more of the output optical signals in use.

An optical fiber has corrugations on an outer surface to dissipate a portion of an input light beam, allowing the remaining portion of the light beam to be coupled to the optical fiber. By dissipating the portion of input light, damage to the optical fiber by uncoupled light is reduced.

A gain flattening filter includes a first optical fiber that has a core, a first cladding, and a second cladding and that has a uniform composition in a length direction; and a pair of second optical fibers fused to both ends of the first optical fiber. The first optical fiber has a first section in which a slanted refractive index grating is formed and a pair of second sections connecting both ends of the first section to the pair of second optical fibers. The first cladding contains a photosensitive material whose refractive index increases upon irradiation with light having a specific wavelength. In the core, a tensile stress remains in the first section. An average MFD of the second sections is larger than an average MFD of the second optical fibers and smaller than an average MFD of the first section.

Plasmonic optical fibers, plasmonic optical sensors and methods of manufacturing the same. A fiber core conveys an optical signal therewithin and provides a plasmonic sensing area exposed to a fluid. The plasmonic sensing area is formed only on a section of an external surface of the fiber core. The plasmonic sensing area provides an interface within the section of the external surface for the conveyed signal to at least partially exit the fiber core and cause a modified optical signal to be conveyed in the fiber core. An optical signal generator may provide the optical signal to the plasmonic optical fiber, an optical signal receiver may discriminate the conveyed optical signal from the modified optical signal and a processor module may analyze the modified optical signal and identifies physical characteristics of the fluid present at the sensing area.

Multi-clad optical fiber cladding light stripper (CLS) comprising an inner cladding with one or more recessed surface regions to remove light propagating within the inner cladding. A CLS may comprise such recessed surface regions along two or more azimuthal angles about the fiber axis, for example to improve stripping efficiency. One or more dimensions, or spatial distribution, of the recessed surface regions may be randomized, for example to improve stripping uniformity across a multiplicity of modes propagating within a cladding. Adjacent recessed surface regions may abut, for example, end-to-end, as segments of a recess that occupies a majority, or even an entirety, of the length of a fiber surrounded by a heat sink. One or more dimensions, or angular position, of individual ones of the abutted recessed surface regions may vary, according to a regular or irregular pattern.

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 distributed temperature sensor (DTS) system includes a light source; a length of fiber filter having been hydrogen darkened prior to assembly of the system; and a DTS fiber. A method for making a filter for a DTS system.

A wear sensing liner for a comminution apparatus. The wear sensing liner comprising: a liner body comprising; a wear surface side defining a wear surface; and an opposed, operatively rear surface side; and at least one sensor carried by the liner body. The at least one sensor being carried by the liner body to sense wear of the wear surface side of the liner body. The at least one sensor being configured to degrade in response to wear of the wear surface side of the liner body and to output a signal representative of the wear of the wear surface side of the liner body.

A ferrule with a fiber of this disclosure includes: a ferrule including a positioning hole, a plurality of fiber holes, and an endface perpendicular to an axial direction of the fiber holes; a lensed fiber with a GRIN lens that has been fusion spliced to a tip of an optical fiber; and a plate that can transmit light propagating through the optical fiber, the plate being attached to the endface of the ferrule, the plate being contacted against with an endface of the lensed fiber that has been inserted into each of the fiber holes, wherein the ferrule is formed with a recess that is depressed from the endface of the ferrule, a refractive index matching material is filled in a space surrounded with the plate and the recess.