Patent ID: 9482925
Filing Date: 2016-11-01
CPC Classification: G02F

Claim Text:
1. A Mach-Zehnder optical modulator for modulating an input optical beam according to an electrical modulation signal, the Mach-Zehnder modulator comprising: an optical structure dividing the input optical beam into two optical beam components propagating in two parallel optical waveguide branches, respectively, and recombining said optical beam components downstream the optical waveguide branches; and a travelling wave electrode extending over the optical waveguide branches and modulating a relative phase of the optical beam components, said travelling wave electrode comprising a plurality of transmission line conductors conveying the electrical modulation signal; a plurality of waveguide electrodes coupled to one of the two parallel optical waveguide branches; and a plurality of active devices disposed between the plurality of transmission line conductors and the plurality of waveguide electrodes, wherein the plurality of active devices comprises an active device having an input electrically connected to a transmission line conductor from the plurality of transmission line conductors and an output electrically connected to a waveguide electrode from the plurality of waveguide electrodes, wherein the input of the active device has a higher impedance than the output of the active device, wherein the active device transfers the electrical modulation signal from the transmission line conductor onto the waveguide electrode according to a voltage transfer function, and wherein the active device is configured to decouple a capacitance of the waveguide electrode from contributing to a capacitance of the traveling wave electrode.