A fiber structure with a circularly polarizing property is proposed.The fiber consists of a round core and a triplelobe stress region in the cladding,which is compatible with single-mode fibers,and it can be fabricated using conventional metal chemical vapor deposition processes.By coating a layer with a high-refractive index,the twist pitch required for resonant coupling is increased to hundreds of micrometers,and the mature pit-in-jacket drawing technique can be used.The polarization filtering properties of the fabricated circularly polarizing fibers are measured experimentally,showing high distinction ratios in a broad frequency region. A fiber structure with a circularly polarizing property is proposed. The fiber consists of a round core and a triple stress region in the cladding, which is compatible with single-mode fibers, and it can be fabricated using conventional metal chemical vapor deposition processes. BY coating a layer with a high-refractive index, the twist pitch required for resonant coupling is increased to hundreds of micrometers, and the mature pit-in-jacket drawing technique can be used. The polarization filtering properties of the fabricated circularly polarizing fibers are measured experimentally, showing high distinction ratios in a broad frequency region.