Integrated optics devices for optical communications

<正>Integrated optics may provide future lightwave communication systems with suchsophisticated options as single-mode wavelength multiplexing circuits or electrooptic swi-tching networks.Several interesting examples of device research toward this goal arebased on directional coupler structures prepared by Ti-diffusion in the electrooptic materi-al LiMbO3,and split electrode arrangements providing alternating phase mismatch alongthe coupler length （△β coupler）. One variety of this device is a switch and amplitudemodulator that includes 6 sections of alternating △β and can operate at data rates inexcess of 100 Mbit/s with drive voltages as low as 3 volts. A second device exampleincludes the incorporation of intersecting dispersion characteristics in a △β coupler,resulting in a tunable coupler filter This device has a measured filter bandwidth of 20