A multicore optical fiber comprises a common cladding and a plurality of core portions disposed in the common cladding. Each of the core portions includes a central axis, a core region extending from the central axis to a radius r.sub.1, the core region comprising a relative refractive index Δ.sub.1, an inner cladding region extending from the radius r.sub.1 to a radius r.sub.2, the inner cladding region comprising a relative refractive index Δ.sub.2, and a depressed cladding extending from the radius r.sub.2 to a radius r.sub.3, the depressed cladding region comprising a relative refractive index Δ.sub.3 and a minimum relative refractive index Δ.sub.3 min. The relative refractive indexes may satisfy Δ.sub.1>Δ.sub.2>Δ.sub.3 min. The mode field diameter of each core portion may greater than or equal to 8.2 μm and less than or equal to 9.5 μm.

The invention relates to a supercontinuum light source comprising a microstructured optical fiber and a pump light source. The microstructured optical fiber comprises a core and a cladding region surrounding the core, as well as a first fiber length section, a second fiber length section and an intermediate fiber length section between said first and second fiber length sections. The first fiber length section comprises a core with a first characteristic core diameter. The second fiber length section comprises a core with a second characteristic core diameter, smaller than said first characteristic core diameter, where said second characteristic core diameter is substantially constant along said second fiber length section. The intermediate length section of the optical fiber comprises a core which is tapered from said first characteristic core diameter to said second characteristic core diameter over a tapered length.

A combined optical coherent tomography (OCT) pressure sensor system includes an optical cable comprising a single-mode core and a multi-mode core. An OCT optical imaging sensor near a distal end of the optical cable can be inserted into a lumen of a living being. First light exiting a distal end of the single-mode core illuminates an interior of the lumen. The OCT optical imaging sensor acquires image information about the interior of the lumen and transmits an optical signal carrying the image information into the distal end of the single-mode core, toward a proximal end of the single-mode core. An optical pressure sensor attached near the OCT optical imaging sensor receives second light from the distal end of the optical cable, senses ambient pressure within the lumen and transmits an optical signal indicative of the ambient pressure into a distal end of the multi-mode core, toward a proximal end of the multi-mode core.

An optical fiber includes: a core portion made of glass; and a cladding portion made of glass, having a refractive index lower than the refractive index of the core portion, and positioned on an outer periphery of the core portion. Further, the cladding portion has an outer diameter smaller than 100 μm, and the core portion has a relative refractive-index difference of 0.32% to 0.40% with respect to the cladding portion.

A method of fabricating a graded-index polymer optical fibre comprises preparing a cladding composition, the cladding composition comprising either a mixture of a cladding polymer and a dopant or a mixture of a cladding polymer precursor and a dopant; forming cladding from the cladding composition around a core, the core comprising a core polymer; and causing diffusion of the dopant into the core such that the dopant has a continuous concentration gradient, according to which concentration gradient the concentration of the dopant increases with radial distance from a centre of the core. The dopant is a compound having a refractive index which is lower than a refractive index of the core polymer. By distributing the dopant such that the dopant concentration is lowest at the centre of the core, the optical attenuation of the graded-index polymer optical fibre may be reduced. Also provided is a graded-index polymer optical fibre obtainable by the method.

The present invention relates to an optical fiber having a core extending parallelly along a central axis of the optical fiber, an inner cladding surrounding the core and an outer cladding surrounding the inner cladding. In particular, the core is up-doped with first and second up-dopants and the inner cladding is up-doped with the second up-dopant. Moreover, the outer cladding is un-doped. Further, the optical fiber has an attenuation of less than 0.2 at a wavelength of 1625 nanometres (nm), the attenuation of less than 0.18 at a wavelength of 1550 nm, or the attenuation of less than 0.32 at a wavelength of 1310 nm and a cable cutoff in a range of 1186 nanometres (nm) to 1194 nm.

An optical fiber filter includes a fiber core, inner cladding, and outer cladding. A refractive index of the fiber core, a refractive index of the inner cladding, and a refractive index of the outer cladding progressively decrease in sequence. The fiber core is configured to transmit at least two mutually different first optical signal modes, the inner cladding is configured to transmit at least two mutually different second optical signal modes, and at least one fiber grating is etched on the fiber core. At least part of optical power of a target first optical signal mode is coupled to only a target second optical signal mode at the fiber grating. The target first optical signal mode is one of the at least two first optical signal modes, and the target second optical signal mode is one of the at least two second optical signal modes.

An optical fiber includes a core that propagates a light that includes a wavelength equal to or larger than 1000 nm and equal to or smaller than 1100 nm. The light propagates in the core at least in an LP01 mode and an LP11 mode. A difference between a propagation constant of the light in the LP01 mode and a propagation constant of the light in the LP11 mode is 1735 rad/m or larger and 4000 rad/m or smaller.

A microstructured optical fiber for generating supercontinuum light. The optical fiber includes a core and a cladding region surrounding the core. The optical fiber includes a first fiber length section, a second fiber length section as well as an intermediate fiber length section between said first and second fiber length sections. The first fiber length section has a core with a first characteristic core diameter larger than about 7 μm. The second fiber length section has a core with a second characteristic core diameter, smaller than said first characteristic core diameter. The intermediate length section of the optical fiber includes a core which is tapered from said first characteristic core diameter to the second characteristic core diameter over a tapered length. Also, a supercontinuum light source including an optical fiber and a pump light source.

A fiber optic cable includes an optical fiber, a strength layer surrounding the optical fiber, and an outer jacket surrounding the strength layer. The strength layer includes a matrix material in which is integrated a plurality of reinforcing fibers. A fiber optic cable includes an optical fiber, a strength layer, a first electrical conductor affixed to an outer surface of the strength layer, a second electrical conductor affixed to the outer surface of the strength layer, and an outer jacket. The strength layer includes a polymeric material in which is embedded a plurality of reinforcing fibers. A method of manufacturing a fiber optic cable includes mixing a base material in an extruder. A strength layer is formed about an optical fiber. The strength layer includes a polymeric film with embedded reinforcing fibers disposed in the film. The base material is extruded through an extrusion die to form an outer jacket.