The present disclosure provides an optical fibre. The optical fibre includes a core extended from a central longitudinal axis to a first radius r1. Further, the optical fibre includes a first trench region extended from a second radius r2 to a third radius r3, a second trench region extended from the third radius r3 to a fourth radius r4 and a cladding region extended from the fourth radius r4 to a fifth radius r5.

An optical fiber includes: a central core portion; an intermediate layer configured to surround an outer periphery of the central core portion; a trench layer configured to surround an outer periphery of the intermediate layer; and a cladding portion configured to surround an outer periphery of the trench layer. The central core portion is made of silica based glass that does not contain germanium (Ge). Δ1>Δ2>Δ3 and ΔClad>Δ3, where Δ1 represents an average maximum relative refractive-index difference of the central core portion relative to pure quartz glass, Δ2 represents an average relative refractive-index difference of the intermediate layer relative to the pure quartz glass, Δ3 represents an average relative refractive-index difference of the trench layer relative to the pure quartz glass, and ΔClad represents an average relative refractive-index difference of the cladding portion relative to the pure quartz glass. Δ1 is equal to or larger than 0.05%.

An assembly for redirecting light emitted by an end-emitting optical fiber into an inner lumen of a body is provided. According to one implementation, the body includes one or more surfaces disposed on or in the body onto which the light is configured to impinge when the end emitting optical fiber is activated, the one or more surfaces being configured to alter the trajectory of the light so that the light is directed to impinge on a light reflector of a cap removably attached to the body, the light reflector of the cap being configured to redirect the light distally into the inner lumen of the body.

In various embodiments, the beam parameter product and/or beam shape of a laser beam is adjusted by directing the laser beam across a path along the input end of a cellular-core optical fiber. The beam emitted at the output end of the cellular-core optical fiber may be utilized to process a workpiece.

A method of manufacturing a multimode optical fiber includes specifying a peak wavelength λ.sub.P for the multimode optical fiber. The peak wavelength λ.sub.P corresponds to a wavelength at which the multimode optical fiber has a maximum bandwidth. The multimode optical fiber comprises a core and a cladding surrounding and directly adjacent to the core. The core has a radius r.sub.1 and a maximum relative refractive index Δ.sub.1,MAX>0. The cladding comprises a depressed-index region having a minimum relative refractive index Δ.sub.3,MIN<0 and a volume v. A draw tension T for the multimode optical fiber is selected based on a correlation relating peak wavelength λ.sub.P to draw tension T, the correlation comprising a correlation constant. The correlation constant K is a function of at least one of Δ.sub.1,MAX, r.sub.1, v, Δ.sub.3,MIN, and λ.sub.P. The multimode optical fiber is drawn from a preform at the draw tension T.

An array-type polarization-maintaining multi-core fiber includes a main outer cladding, fiber core units, and stress units. The fiber core units and the stress units are arranged to form a unit array including one central unit and any unit in the unit array being equidistantly arranged from adjacent units thereof. Provided is at least one pair of stress units, each pair of stress units being arranged symmetrical about one fiber core unit to form a polarization-maintaining fiber core unit. The fiber core units each include a fiber core and an inner cladding surrounding a core layer. A portion outside the fiber core units and the stress units is the main outer cladding. The fiber can greatly enhance spectral efficiency of an optical transmission system, and improve fiber communication capacity.

The present invention relates to an ultra-low loss optical fiber for long haul communications (100) comprising a core region (102) defined by a core relative refractive index and a cladding region surrounding the core region, defined by a cladding relative refractive index. In particular, the core region comprises a relative refractive index in a range of −0.06% to +0.06% and the cladding region is down-doped for entire radial cladding thickness. Moreover, the cladding region further comprises an inner cladding region (104) defined by an inner cladding relative refractive index and an outer cladding region (106) defined by an outer cladding relative refractive index. The inner cladding relative refractive index is less than the outer cladding relative refractive index.

A peripheral light-emitting linear light guide member is composed of an optical fiber including a core having an outer periphery surface exposed from a cladding at one end in a longitudinal direction, and a light-scattering member covering an entire periphery of the outer periphery surface at an exposed portion of the core over a predetermined axial length range. The light-scattering member scatters a light emitted from the outer periphery surface of the core. In the light-scattering member, light-scattering particles are dispersion-mixed with an optically transparent base material having a higher refractive index than a refractive index of the core. An amount of the light-scattering particles around an outer periphery of the core is higher at a distal end of the light-scattering member than at an end closer to the cladding.

A peripheral light-emitting linear light guide member is composed of an optical fiber including a core having an outer periphery surface exposed from a cladding at one end in a longitudinal direction, and a light-scattering member covering an entire periphery of the outer periphery surface at an exposed portion of the core over a predetermined axial length range. The light-scattering member scatters a light emitted from the outer periphery surface of the core. In the light-scattering member, light-scattering particles are dispersion-mixed with an optically transparent base material having a higher refractive index than a refractive index of the core. An amount of the light-scattering particles around an outer periphery of the core is higher at a distal end of the light-scattering member than at an end closer to the cladding.

A method of processing by controlling one or more beam characteristics of an optical beam may include: launching the optical beam into a first length of fiber having a first refractive-index profile (RIP); coupling the optical beam from the first length of fiber into a second length of fiber having a second RIP and one or more confinement regions; modifying the one or more beam characteristics of the optical beam in the first length of fiber, in the second length of fiber, or in the first and second lengths of fiber; confining the modified one or more beam characteristics of the optical beam within the one or more confinement regions of the second length of fiber; and/or generating an output beam, having the modified one or more beam characteristics of the optical beam, from the second length of fiber. The first RIP may differ from the second RIP.