JPWO2021009211A5

JPWO2021009211A5 -

Info

Publication number: JPWO2021009211A5
Application number: JP2021570392A
Authority: JP
Publication date: 2023-04-04

Claims

1. A method of making an anti-resonant hollow core fiber having a hollow core extending along the longitudinal axis of the fiber and a cladding region containing a plurality of anti-resonant elements and surrounding the hollow core, comprising:
(a) a cladding tube (2) having a cladding inner bore and a cladding longitudinal axis with a cladding wall (2a) defined by an inner side and an outer side extending along said cladding longitudinal axis; and
(b) providing a plurality of anti-resonant element preforms (4);
(c) positioning said antiresonant element preform (4) at a target position inside said cladding tube wall (2a), said hollow core fiber primary preform (1) having a hollow core region and a cladding region; ), and
(d) drawing the primary preform (1) to form hollow core fibers or further processing the primary preform ( 1) into a secondary preform from which hollow core fibers are drawn;
with
In the process of further processing,
(i) stretching;
(ii) collapse,
(iii) collapse and simultaneous stretching;
(iv) collapse of additional cladding material;
(v) collapse of additional cladding material followed by drawing;
(vi) collapsing and co-stretching additional cladding material;
A manufacturing method wherein one or more thermoforming processes of
Providing and/or arranging said anti-resonant element preform (4) and/or performing the process according to step (d) using an encapsulant or bonding material (5) containing amorphous _SiO2 particles A method characterized in that it includes fixing and/or sealing measures of

Method according to claim 1, characterized in that the anti-resonant element preform (4) is fixed inside the cladding tube (2) using the sealing or bonding material.

Said anti-resonant element preform (4) is configured in a cylindrical shape and has two opposite end regions and is fixed to either one using said encapsulant or bonding material (5). 3. A method according to claim 2, characterized in that it is carried out only at the edge region or only at both edge regions.

A cladding tube (2) of circular internal cross-section is provided, said inner side of said cladding tube wall (2a) being provided with a longitudinal structure having a recess in which said anti-resonance element preform (4) is fixed. 2. The method of claim 1 , characterized by:

5. The method of claim 4, wherein said longitudinal structure is a longitudinal groove.

Said encapsulant or bonding material (5) is housed in said recess of said longitudinal structure (3) and said anti-resonant element preform (4) is placed in said target position according to step (c). 5. A method according to claim 4, characterized in that it is in contact with the encapsulant or bonding material (5) during the process.

5. Method according to claim 4 , characterized in that the longitudinal structure (3) inside the cladding tube is made by drilling, sawing, milling, cutting or grinding.

The positioning of the anti-resonant element preform (4) inside the cladding tube includes fixing with a positioning template inserted into the cladding inner bore, the positioning template being adapted to the anti-resonant element preform. 3. A method according to claim 2 , characterized by having a plurality of radially outwardly facing retaining elements for positioning the form in said target position.

9. Method according to claim 8 , characterized in that the positioning template is used only in the regions of both cladding tube end faces.

Said anti-resonant element preform (4) is composed of a plurality of structural elements (4a; 4b) nested together, said structural elements (4a; 4b) comprising said encapsulant or bonding material ( A method according to claim 1 , characterized in that they are fixed to each other using 5).

The fixing of the cylindrical structural element (4a; 4b) by the use of the sealing or bonding material (5) can be done only at one end of the structural element (4a; 4b) or at both ends. 11. A method according to claim 10, characterized in that it is performed only at the ends.

In order to carry out the process according to step (d), said preform (1) is connected to a holder and the bonding between said preform (1) and said holder is made by said encapsulant or bonding material (5). A method according to any one of claims 1 to 10 , characterized in that the

In order to carry out the process according to step (d), said preform (1) is connected to a gas connection and the bond between said preform (1) and said gas connection is achieved by said sealing or bonding material ( A method according to any one of claims 1 to 10, characterized in that it is carried out according to 5).

open ends of said anti-resonant element pre-form (4) and/or individual structural elements (4a; 4b) of said anti-resonant element pre-form (4), and/or Method according to any one of the preceding claims, characterized in that any annular gaps between pipe elements are sealed by said sealing or jointing material ( 5 ).

11. Any of claims 1 to 10 , characterized in that said sealing or bonding material (5) is compressed by heating and preferably vitrified by heating during the process according to step (d). The method according to item 1.

A method according to any one of the preceding claims, characterized in that the antiresonant elements ( 4 ) are arranged with odd symmetry around the hollow core.

1. A method of manufacturing an anti-resonant hollow-core fiber preform having a hollow core extending along a longitudinal axis of the fiber and a cladding region containing a plurality of anti-resonant elements and surrounding the hollow core, the method comprising:
(a) a cladding tube (2) having a cladding inner bore and a cladding longitudinal axis with a cladding wall (2a) defined by an inner side and an outer side extending along said cladding longitudinal axis; and
(b) providing a plurality of anti-resonant element preforms (4);
(c) for said hollow-core fiber having a hollow core region and a cladding region, with said anti-resonant element preforms (4) arranged at respective target positions inside said cladding wall (2a); forming a primary preform (1) of
(d) optionally further processing said primary preform (1) into a secondary preform for said hollow core fiber;
with
In the further processing step,
(i) stretching;
(ii) collapse,
(iii) collapse and simultaneous stretching;
(iv) collapse of additional cladding material;
(v) collapse of additional cladding material followed by drawing;
(vi) collapsing and co-stretching additional cladding material;
A manufacturing method wherein one or more thermoforming processes of
Providing and/or arranging said anti-resonant element preform (4) and/or performing the process according to step (d) using an encapsulant or bonding material (5) containing amorphous _SiO2 particles A method characterized in that it includes fixing and/or sealing measures of