Nonsymmetric Interferometer Research Articles

High-speed low-voltage modulation with a nonsymmetric Mach-Zehnder interferometer

The authors demonstrate broadband optical modulation with a Ti:LiNbO/sub 3/ nonsymmetric interferometer at microwave frequencies up to 16 GHz. The 3-dB bandwidth of 8.7 GHz is only slightly less than the theoretical limit of 9.6 GHz for a 1-cm-long device. The device uses a 2- mu m-thick gold-plated asymmetric stripline electrode, with a characteristic impedance of 40 Omega and ohmic loss of 3 dB/cm at 10 GHz. The DC switching voltage is 6.5 V, and the on/off ratio is -16 dB. Fabrication tolerances in the nonsymmetric interferometer are much less strict than for directional coupler modulators with comparable performance, making this device a better candidate for use in communications systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Voltage tunable LiNbO_3 wavelength filters

We describe here the design and operation of voltage tunable wavelength filters fabricated in titanium diffused LiNbO(3). The devices, based on the nonsymmetric interferometer, have channel separations of 11-31 nm at lambda= 1300 nm, and tuning rates of 3-10 nm/V. The periodic wavelength response of these filters allows them to be cascaded to combine or separate 2(N) channels in N stages.