Abstract:The semi leaky modes in doubly clad chiral optical fibers with the core,inner and outer cladding are chiral media have been investigated.The effective refractive index and the power loss coefficient versus fiber chirality for several lower order modes in single and doubly clad chiral optical fibers are presented.The results demonstrate that the characteristics of semi leaky modes in doubly clad chiral optical fibers are very different from those in single clad chiral optical fibers.The semi leaky modes can also exist in the single clad optical fiber in which the core material is achiral and the cladding material is chiral.