5-Gbit/s BER performance on an all fiber-optic add/drop device based on a taper-resonator-taper structure

We present an all fiber-optic add/drop device based on a taper-resonator-ta per structure with improved characteristics. Several gigahertz bandwidths a re observed using microspheres having diameters ranging from 30 to 50 mu m Extinction ratios as high as 26 dB of the dropped channel are obtained due to nearly ideal coupling and phase matching between the fiber tapers and th e small resonator. This is the first time that bit-error rate (BER) measure ments have been performed on such couplers, For a device with an optical ba ndwidth of 3.8 GHz, the BER shows less than 2-dB penalty at 5 Gbit/s and no signs of an error floor.