High-isolation single-taper filters

The interferornetric properties of an abrupt nonadiabatic taper in an optical fiber can be used to create an all fiber wavelength filter. To date the maximum attenuation possible from a single taper has typically been 4 to 5 dB. In this paper we report the realization of single taper filters with significantly unproved performance. Typical optical properties for 1300/1550 nm filters include as much as 30 dB attenuation at the stop wavelength and less than 0. 5 dB insertion loss at the pass wavelength. Similar filters have been built for other wavelength combinations including 980/1550 and 1480/1550 mu. The operation performance and application of these high isolation single taper filters will be presented and discussed in this paper.