Hideaki OKAYAMA, Yutaka OKABE and Takeshi KAMIJOH

R&D Group, Oki Electric Industry Co., Ltd., 550-5, Higashiasakawa, Hachioji, Tokyo, 193 Japan

(Received December 3, 1996; Accepted January 28, 1997)

We developed a flat passband acoustooptic filter. For the passband flattening, cascaded bandpass and notch filters with different mode converter lengths and conversion strengths were used. We attained a flat passband with flatness of less than 1 dB in the 2 nm range using the device with a second- to first-stage mode converter length ratio of 1.2.

Key words : wavelength filter, optical waveguide, acoustooptic effect, cascaded structure, passband flattening