Patent ID: 6198854
Filing Date: 2001-03-06
Classification: G02F

Abstract:
A Mach-Zehnder modulator modulating light intensity in response to an applied voltage, the modulator comprising:a substrate;at least one input optical waveguide on the substrate and to which a light signal is supplied;a first optical waveguide and a second optical waveguide branching from the input optical waveguide and located on the substrate, each of the first and second optical waveguides comprising at least a first cladding layer, a multiple quantum well structure including at least one well layers and a second cladding layer, successively arranged on the substrate, the at least one well layer of the multiple quantum well structure of the first optical waveguide being thicker than the at least one well layer of the multiple quantum well structure of the second optical waveguide;a first electrode and a second electrode for applying a voltage to the first optical waveguide and the second optical waveguide, respectively; andan output optical waveguide on the substrate and connected to the first optical waveguide and the second optical waveguide and for outputting the light signal, wherein the first optical waveguide has a refractive index increasing and the second optical waveguide has a refractive index decreasing in response to the same modulating voltage applied to the first and second electrodes, whereby the light signal emerging from the output optical waveguide is modulated.