The effects of fusion and tapering conditions on biconical taper fiber filters are studied experimentally. A Gaussian profile model for the prediction of fiber taper shape is presented. We have fabricated the passband fiber filter with narrow band (3 dB width 4 nm), and band regection fiber filters with central band rejection wavelengthes of 1553 nm(loss -6.6 dB) and 1559 nm (loss -19.6 dB), respectively.