Sealing of a cane assembly using a rapid, heat curing sealing material for hollow core fiber manufacturing

A manufacturing method for forming a hollow-core fiber (“HCF”) by first forming a cane assembly, the method comprising:

• inserting pressurization tubes into a first end of a cane;
• applying a sealing material to a region at the first end of the cane, resulting in a liquid seal, at the first end of the cane, through which the inserted pressurization tubes extend, wherein the sealing material is an addition-curing silicone elastomer-based material;
• curing the sealing material, by applying heat, to the sealing material, at a curing temperature between 70 and 200 degrees Celsius (° C.) for a curing duration that is less than two hours, resulting in a pressure seal, at the first end of the cane, through which the inserted pressurization tubes extend, the cane assembly comprising an arrangement of the cane, the inserted pressurization tubes, and the cured sealing material resulting from the inserting, applying, and curing steps;
• pressurizing the cane assembly, by pumping an inert gas into the first end of the cane through the pressurization tubes;
• and
• forming the HCF, by vertically drawing the cane, by a second end of the cane, through a heated chamber, while the cane assembly is under pressure from the inert gas being pumped into the first end of the cane.

A cane assembly that is used in forming a hollow-core fiber (“HCF”), the cane assembly comprising:

• a cane, comprising:
• an outer glass tube having an outer diameter that has been drawn to a first diameter that is less than 10 mm;
• a plurality of tubes, groups of tubes among which are nested and fused to form a plurality of nested tubes of the cane, the plurality of nested tubes being spaced apart along an inner circumference of the outer glass tube and being fused to an inner surface of the outer glass tube;
• and
• a central opening corresponding to a first space defined by the inner circumference of the outer glass tube and an outer circumference of each of the plurality of nested tubes;
• a core pressurization tube that is inserted and affixed within the central opening of the cane;
• a plurality of pressurization capillary tubes each of which is inserted, at a first end of the cane, in one of the plurality of tubes that is arranged to form the plurality of nested tubes of the cane;
• a sleeve tube through which the first end of the cane has been inserted, the sleeve tube being affixed to a portion of an outer surface of the first end of the cane;
• and
• a sealing material that, after being heat cured at a curing temperature between 70 and 200 degrees Celsius (° C.) for a curing duration that is less than two hours, forms a pressure seal, at the first end of the cane, that prevents an inert gas that is pumped into the cane through the core pressurization tube and the plurality of pressurization capillary tubes from escaping through the first end of the cane assembly during vertical drawing of a second end of the cane to form an HCF, the sealing material being an addition-curing silicone elastomer-based material including a mixture containing a silicone polymer and a catalyst at a weight ratio of 9:1.