Terahertz hollow core waveguide
A terahertz hollow core waveguide includes several successively cascaded waveguide units, and the waveguide units includes fiber core and cladding. The fiber core is composed of air, and the cladding is composed of dielectric rings, air rings, support strips, and an outer cladding. The medium rings and the air rings are successively surrounded on the outside of the fiber core, and the outer cladding is surrounded on the outside of the outermost air ring. All support strips in the same air ring of the same waveguide unit form a support strip group, and the support strips in the support strip group are arranged along the circumferential direction to connect two adjacent dielectric rings in the same waveguide unit or to connect the outermost dielectric ring and the outer cladding in the same waveguide unit.
1. A terahertz hollow core waveguide, comprising cascaded waveguide units, wherein each of the waveguide units comprises a core and a cladding;
wherein the core is composed of air, the cladding comprises dielectric rings, air rings, an outer cladding, and one or more support strip groups, wherein the dielectric rings and the air rings are alternately arranged around the core, and the outer cladding is arranged on an outside of an outermost air ring,
wherein at least one support strip group is provided in each air ring of the terahertz hollow core waveguide, wherein all support strips in an air ring of a waveguide unit form a support strip group, and the support strips in a support strip group are arranged along a circumferential direction to connect two adjacent dielectric rings in the waveguide unit or to connect an outermost dielectric ring and the outer cladding in the waveguide unit, wherein for any two adjacent waveguide units, at least one of the waveguide units does not have support strips in at least one of the air rings.
2. The terahertz hollow core waveguide according to claim 1 , wherein the air rings, the dielectric rings and the outer cladding are concentric rings, all the air rings have a same width, and all the dielectric rings have a same width.
3. The terahertz hollow core waveguide according to claim 1 , wherein for arbitrarily two adjacent air rings in the waveguide unit, at most one air ring is provided with a support strip group.
4. The terahertz hollow core waveguide according to claim 1 , wherein a number of dielectric rings N meets a condition of 2≤N≤b.
5. The terahertz hollow core waveguide according to claim 1 , wherein a width d s,n of a support strip in an nth air ring meets conditions of d s,n ≥d m,m , M n d s,n <2πd r,n /4, and 1≤M n ≤N, wherein n denotes an order number of air ring from inside to outside along a radial direction of the waveguide, M n denotes a number of support strips located on a same cross section of the waveguide, d m,n is a width of the dielectric ring in an nth ring, d r,n is an outer diameter of the nth dielectric ring and N denotes a number of dielectric rims.
6. The terahertz hollow core waveguide according to claim 1 , wherein each waveguide unit has at most one air ring provided with a support strip group.
7. The terahertz hollow core waveguide according to claim 1 , wherein the support strip groups are periodically arranged along the axial direction of the waveguide, for each period, the support strip groups are arranged in order, firstly in a first air ring, then in a second air ring, etc., and until up to an N-th air ring, wherein an air ring adjacent to the core is denoted as the first air ring and the other air rings are named according to an order of the air rings arranged radially along the waveguide, wherein N is a number of air rings.
8. The terahertz hollow core waveguide according to claim 1 , wherein the support strip groups are periodically arranged along an axial direction of the waveguide, and the support strip groups in a period are successively arranged in order, firstly in a first air ring, then in a second air ring, etc., and until up to an Nth air ring, and then arranged in order from an (N−1)-th air ring and until up to the second air ring, wherein an air ring adjacent to the core is denoted as the first air ring and the other air rings are named according to an order of the air rings arranged radially along the waveguide, wherein N is a number of air rings.
9. The terahertz hollow core waveguide according to claim 3 , wherein the support strips in a same air ring are evenly distributed along the circumferential direction in the waveguide unit.
10. The terahertz hollow core waveguide according to claim 9 , wherein lengths K s,n of the support strips in an nth air ring in a waveguide unit meet a condition of d a,n <L s,n <100d m,n wherein d m,n is a width of an nth dielectric ring and d a,n is a width of an nth air ring.