Novel fiber coupler tapering process using a microheater

A novel fiber tapering process using a microheater is proposed and fiber couplers have been fabricated by means of this method. This heater is excellent for producing a 12.4-mm-wide, stable heat region controlled by applied current. Wavelength-flattened couplers with very low losses are fabricated. Taper slope angles are far more gradual than that obtained by stationary burner flames, and the length of the fiber region deformed by tapering is 11.8 mm. The average excess loss at 1.31 and 1.55 mu m is 0.13 dB with a maximum value of 0.3 dB.<
>