A novel hollow core anti resonant fiber based on a dual tube structure with nested tubes was proposed and numerically studied for near infrared single polarization single mode operation.Unlike conventional anti resonant structures with polygonal cladding tubes,the proposed fiber consists of two identical thin walled tubes symmetrically positioned within the outer cladding,each internally nested with a slightly smaller radius tube.The introduction of the nested tubes enhances the confinement loss of higher order modes,thereby enabling the fiber to achieve single polarization single mode operation.Simulation results demonstrate that the fiber exhibits single polarization characteristics across the wavelength range of 1450 nm to 1700 nm,and single polarization single mode operation within the range of 1639 nm to 1672 nm,with a bandwidth of 33 nm.This fiber design holds significant potential for the development of high performance single polarization single mode fiber devices.