Method for dividing optical fibre
A method for dividing an optical fibre comprises providing a hollow core optical fibre having a length, a cladding which comprises a microstructure, a hollow core surrounded by the cladding, and a negative pressure portion in which the pressure is below atmospheric pressure that extends over at least a portion of the length; and cleaving the hollow core optical fibre at a divide location within the negative pressure portion to divide the hollow core optical fibre into two parts and provide an end facet at the divide location on one or both of the parts.
1 . A method for dividing an optical fibre, comprising:
providing a hollow core optical fibre having a length, a cladding which comprises a microstructure, a hollow core surrounded by the cladding, and a negative pressure portion in which the pressure is below atmospheric pressure that extends over at least a portion of the length; and
cleaving the hollow core optical fibre at a divide location of the fibre at which the pressure is below the atmospheric pressure to divide the hollow core optical fibre into two parts and provide an end facet at the divide location on a first part of the two parts.
2 . The method according to claim 1 , wherein the cleaving provides the end facet on the first part such that the first part is suitable to be spliced to another optical element.
3 . The method according to claim 1 , wherein the hollow core optical fibre has at least one closed end for inhibiting ingress of contaminants into the cladding and/or the hollow core.
4 . The method according to claim 3 , wherein the at least one closed end is closed by a hermetic seal.
5 . The method according to claim 3 , wherein the divide location is within 1 metre of the at least one closed end so that dividing the hollow core optical fibre into the two parts removes a part with the closed end from a longer part of the hollow core optical fibre.
6 . The method according to claim 5 , wherein the divide location is 300 mm or less from the at least one closed end.
7 . The method according to claim 1 , wherein each of the two parts has a length of at least 5 metres.
8 . The method according to claim 1 , wherein the hollow core optical fibre comprises a coating around the cladding.
9 . The method according to claim 8 , wherein, before cleaving the hollow core optical fibre, the method further comprises:
removing a portion of the coating from around the cladding at a window location within the negative pressure portion to expose a window of cladding;
and wherein the divide location is within the window.
10 . The method according to claim 9 , comprising removing the portion of the coating from around the cladding using a mechanical optical fibre stripping device.
11 . The method according to claim 9 , comprising removing the portion of the coating from around the cladding using a non-mechanical optical fibre stripping technique.
12 . The method according to claim 9 , wherein, after removing the portion of the coating and before cleaving the hollow core fibre, the method further comprises cleaning an outer surface of the cladding in the window including cleaning at the divide location.
13 . The method according to claim 9 , wherein the window has a width along the hollow core optical fibre of 100 mm or less.
14 . The method according to claim 9 , wherein the window has a width along the hollow core optical fibre in the range of 20 mm to 50 mm.
15 . The method according to claim 8 , wherein cleaving the hollow core optical fibre comprises cleaving the coating.
16 . The method according to claim 15 , further comprising, after cleaving the hollow core optical fibre, removing a portion of the coating from around the cladding adjacent to an end of one of the parts.
17 . The method according to claim 1 , wherein the hollow core optical fibre is an antiresonant hollow core optical fibre.
18 . The method according to claim 1 , wherein the hollow core optical fibre is a photonic bandgap hollow core optical fibre.
19 . A method for dividing an optical fibre, comprising:
providing a hollow core optical fibre having a length, a cladding which comprises a microstructure, a hollow core surrounded by the cladding, and a negative pressure portion in which the pressure is below atmospheric pressure that extends over at least a portion of the length; and
separating the hollow core optical fibre at a divide location of the fibre at which the pressure is below the atmospheric pressure to divide the hollow core optical fibre into two parts, using a separating technique configured to avoid formation of shards from the microstructure.
20 . The method according to claim 19 , wherein the separating technique comprises delivering heat energy to the hollow core optical fibre.