All Fiber tunable loss filter

A simple all-fiber tunable loss filter using a buffer stripped high bend loss fiber is presented in this paper. The center wavelength of the filter is set merely by changing the bend radii of the macro bend fiber that avoids the complex structures in the fiber of previous all-fiber filters. The proposed tunable filter can give an isolation of 20 dB for a wavelength range of 40 nm and has wide range of applications.