Antiresonant hollow core fiber with low-index coating

An optical cable comprising:

• a hollow core fiber (HCF) comprising:
• a cladding structure extending in a longitudinal direction along a length of the HCF;
• one or more antiresonant (AR) structures extending in the longitudinal direction along the length of the HCF and located in an interior region of the cladding structure, wherein the one or more AR structures form a hollow central core for guiding light;
• and
• a low-index coating at least partially surrounding the cladding structure, wherein a refractive index of the low-index coating is lower than a refractive index of the cladding structure, wherein at least one of the refractive index or a thickness of the low-index coating is configured to provide guiding of leakage light, wherein the leakage light includes that decouples from the hollow central core;
• wherein the HCF includes one or more cladding light guiding sections extending longitudinally along the HCF and one or more cladding light stripping sections extending in the longitudinal direction along the length of the HCF, wherein the low-index coating in the one or more cladding light guiding sections has a first thickness, wherein the low-index coating in the one or more cladding light stripping sections has
• a second thickness smaller than the first thickness;
• and
• one or more beam dumps in at least some of the one or more cladding light stripping sections to at least one of absorb the leakage light or direct the leakage light out of the optical cable.

An optical fiber comprising:

• one or more hollow core sections, each of the one or more hollow core sections formed as a hollow core fiber (HCF) comprising:
• a cladding structure extending in a longitudinal direction along a length of the HCF;
• and
• one or more antiresonant (AR) structures extending in the longitudinal direction along the length of the HCF and located in an interior region of the cladding structure, wherein the one or more AR structures form a hollow central core for guiding light;
• one or more solid core sections, each of the one or more solid core sections formed as a solid core fiber comprising:
• a solid core extending in the longitudinal direction;
• and
• a solid cladding section surrounding the solid core;
• and
• a low-index coating at least partially surrounding the one or more hollow core sections and the one or more solid core sections, wherein a refractive index of the low-index coating is lower than a refractive index of the cladding structure of each of the one or more hollow core sections and the solid core of each of the solid core sections.