Hollow-core fiber and optical transmission system

An optical transmission system, comprising:

• an optical transmitter, configured to transmit signal light;
• a hollow-core fiber, configured to transmit the signal light, wherein the hollow-core fiber comprises N first tubular units, N second tubular units, and a protection sleeve, wherein
• the N first tubular units are arranged circumferentially and abut against the protection sleeve;
• the N second tubular units are in one-to-one correspondence with the N first tubular units, and each of the N first tubular units is nested in a corresponding second tubular unit, to form, together with the second tubular unit, a cladding layer that confines light beam propagation within a fiber core;
• and
• a cross section of the second tubular unit comprises at least one arc structure, a first endpoint and a second endpoint of each of the at least one arc structure are in contact with the protection sleeve, a central angle of the at least one arc structure is 180 degrees to 340 degrees, and N is a positive integer greater than or equal to 5;
• and
• an optical receiver, configured to receive the signal light.