The recent, a large capacity of communication is required in order to it is in proportion to capacity of information communication increase and to satisfy a demand because of the demand about Internet, a multimedia service of Video of internet protocol(VoIP), Audio/Video steaming. DWDM(Dense Wavelength Division Multiplexing) technique has been emerged as the method of solving it without additional optical fiber network building and hish-speed equipment. Therefore this thesis proposed the optical filter of fiber/multilayer slab coupled structure combining it to multilayer slab waveguide by polishing the cladding of one side of fiber to design the optical filter having these functions. The optical filter proposed as the simulation result satisfies DWDM filter characteristic; 1) when the separation distance between fiber and slab is $4.15{mu}m$ at the communication window of $1.5{mu}m$, the polarization independence is 65nm, 2) when the center wavelengths about TM mode and TE mode are each ${lambda}_0=1.54946;{mu}m$ and ${lambda}_0=1.6144;{mu}m$ and, FWHM(Full at Half Maximun) is 0.1nm.