A microstructured multicore optical fibre (MMOF) includes a cladding in which a plurality of basic cells are formed that run along the MMOF. Each of the basic cells includes a core, and at least one of the basic cells is surrounded by a plurality of longitudinal areas that run parallel to the core along the MMOF and are arranged in a hexagonal arrangement around the core. The longitudinal areas are spaced by a lattice constant Λ. Sides of the hexagon can be shared with adjacent basic cells.

A microstructured multicore optical fibre (MMOF) includes a cladding in which a plurality of basic cells are formed that run along the MMOF. Each of the basic cells includes a core, and at least one of the basic cells is surrounded by a plurality of longitudinal areas that run parallel to the core along the MMOF and are arranged in a hexagonal arrangement around the core. The longitudinal areas are spaced by a lattice constant Λ. Sides of the hexagon can be shared with adjacent basic cells.

The present invention relates to an optical fiber device for removing cladding light, an apparatus and a method for etching the same. The optical fiber device comprises: a first optical fiber section through an N.sup.th optical fiber section arranged in sequence along a light travelling direction; and a first tapered coupling section coupling a K.sup.th optical fiber section and a (K+1).sup.th optical fiber section, where the K.sup.th optical fiber section is any one of the first optical fiber section through the N.sup.th optical fiber section and the (K+1).sup.th optical fiber section is any one of the first optical fiber section through the N.sup.th optical fiber section adjacent to the K.sup.th optical fiber section, wherein the K.sup.th optical fiber section comprises: at least one first subsection and at least one second subsection alternately arranged along the light travelling direction, each of the at least one first subsection having a diameter D.sub.2K−1 and a length L.sub.2K−1; and each of the at least one second subsection having a diameter D.sub.2K and a length L.sub.2K; and a second tapered coupling section coupling the first subsection and the second subsection adjacent to the first subsection, wherein the diameter D.sub.2K−1 and the length L.sub.2K−1 of the first subsection and the diameter D.sub.2K and the length L.sub.2K of the second subsection of the K.sup.th optical fiber section and a diameter D.sub.2K+1 and a length L.sub.2K+1 of the first subsection and a diameter D.sub.2K+2 and a length L.sub.2K+2 of the second subsection of the (K+1).sup.th optical section satisfy D.sub.2K−1>D.sub.2K, D.sub.2K+1>D.sub.2K+2, L.sub.2K−1>L.sub.2K+1, L.sub.2K>L.sub.2K+2 and D.sub.2K−1=D.sub.2K+1, and satisfy D.sub.2K>D.sub.2K+2 for odd K and D.sub.2K<D.sub.2K+2 for even K (where N is a natural number, and K is any natural number satisfying 1≤K≤N−1).

The present invention relates to an optical fiber device for removing cladding light, an apparatus and a method for etching the same. The optical fiber device comprises: a first optical fiber section through an N.sup.th optical fiber section arranged in sequence along a light travelling direction; and a first tapered coupling section coupling a K.sup.th optical fiber section and a (K+1).sup.th optical fiber section, where the K.sup.th optical fiber section is any one of the first optical fiber section through the N.sup.th optical fiber section and the (K+1).sup.th optical fiber section is any one of the first optical fiber section through the N.sup.th optical fiber section adjacent to the K.sup.th optical fiber section, wherein the K.sup.th optical fiber section comprises: at least one first subsection and at least one second subsection alternately arranged along the light travelling direction, each of the at least one first subsection having a diameter D.sub.2K−1 and a length L.sub.2K−1; and each of the at least one second subsection having a diameter D.sub.2K and a length L.sub.2K; and a second tapered coupling section coupling the first subsection and the second subsection adjacent to the first subsection, wherein the diameter D.sub.2K−1 and the length L.sub.2K−1 of the first subsection and the diameter D.sub.2K and the length L.sub.2K of the second subsection of the K.sup.th optical fiber section and a diameter D.sub.2K+1 and a length L.sub.2K+1 of the first subsection and a diameter D.sub.2K+2 and a length L.sub.2K+2 of the second subsection of the (K+1).sup.th optical section satisfy D.sub.2K−1>D.sub.2K, D.sub.2K+1>D.sub.2K+2, L.sub.2K−1>L.sub.2K+1, L.sub.2K>L.sub.2K+2 and D.sub.2K−1=D.sub.2K+1, and satisfy D.sub.2K>D.sub.2K+2 for odd K and D.sub.2K<D.sub.2K+2 for even K (where N is a natural number, and K is any natural number satisfying 1≤K≤N−1).

A method of fabricating an optical fibre preform is disclosed comprising using a subtractive process on an optical monolith to define therein at least a transverse section of the optical fibre preform, wherein the transverse section comprises at least two regions with different refractive indexes. An optical fibre preform fabricated in accordance with the method is also disclosed along with a method of assembling optical components using a subtractive process to define a first interconnecting feature in or for use with a first optical component; using a subtractive process to define a second interconnecting feature in or for use with a second optical component; and coupling the first and second components together using the first and second interconnecting features such that the coupling dictates a passive alignment of the first and second components.

A method of fabricating an optical fibre preform is disclosed comprising using a subtractive process on an optical monolith to define therein at least a transverse section of the optical fibre preform, wherein the transverse section comprises at least two regions with different refractive indexes. An optical fibre preform fabricated in accordance with the method is also disclosed along with a method of assembling optical components using a subtractive process to define a first interconnecting feature in or for use with a first optical component; using a subtractive process to define a second interconnecting feature in or for use with a second optical component; and coupling the first and second components together using the first and second interconnecting features such that the coupling dictates a passive alignment of the first and second components.

A method of fabricating an optical fiber, the method including providing a core portion including a doped portion having greater than or equal to 1.6 wt. % of a halide dopant and eliminating seed precursor sites at an exterior surface of the core portion, the seed precursor sites forming seeds in the optical fiber, wherein the eliminating the seed precursor sites includes one or more of: (i) fabricating the core portion by densifying an exterior portion of a silica soot body prior to exposing the silica soot body to the halide dopant, and (ii) exposing the exterior surface of the core portion to a reactive etchant. The method further including forming an optical fiber preform by applying cladding material to the exterior surface of the core portion and drawing the fiber preform into the optical fiber.

The present disclosure relates to a method of forming a tapered optical fiber, where the optical fiber has a cladding encasing a core and has an initial outer diameter. The method involves applying opposing forces to spaced apart sections of the optical fiber. The spaced apart sections define a length portion representing a waist region. While applying the opposing forces, simultaneously applying heat to the waist region to gradually produce a taper of the optical fiber within the waist region. The taper has a first diameter at a midpoint of the waist region which is less than the initial outer diameter. An etch operation is then performed by chemically etching at least a subportion of the waist region of the optical fiber to reduce the subportion to a second diameter which is less than the first diameter.

The present disclosure relates to a method of forming a tapered optical fiber, where the optical fiber has a cladding encasing a core and has an initial outer diameter. The method involves applying opposing forces to spaced apart sections of the optical fiber. The spaced apart sections define a length portion representing a waist region. While applying the opposing forces, simultaneously applying heat to the waist region to gradually produce a taper of the optical fiber within the waist region. The taper has a first diameter at a midpoint of the waist region which is less than the initial outer diameter. An etch operation is then performed by chemically etching at least a subportion of the waist region of the optical fiber to reduce the subportion to a second diameter which is less than the first diameter.

A method for manufacturing an optical fiber preform includes: adding an alkali metal element or an alkaline earth metal element to an inner surface of a glass pipe made of silica-based glass; reducing a diameter of the glass pipe after the adding; etching an inner surface of a continuous section of the glass pipe in a longitudinal direction after the reducing; and collapsing the glass pipe after the etching. At least one of the adding, the reducing, the etching, and the collapsing includes performing a local etching on an inner surface of a section of the glass pipe that is shorter than the continuous section.