Patent ID: 7991298

Claim:
An optical modulation system comprising: a Mach-Zehnder waveguide comprising: an input part of an optical signal, a branching part where the optical signal is branched, the branching part connecting to the input part, a first arm, the first arm being configured to act as a waveguide, wherein one of the optical signal branched from the branching part propagates though the first arm, a second arm, the second arm being configured to act as a waveguide, wherein the remaining optical signal branched from the branching part propagates though the second arm, a combining part combining the optical signals, the optical signals outputted from the first arm and the second arm, and an output part outputting the optical signal, the optical signal being combined at the combining part; a first intensity modulator provided on the first arm, the first intensity modulator controlling amplitude of the optical signal propagating through the first arm; a second intensity modulator provided on the second arm, the second intensity modulator controlling amplitude of the optical signal propagating through the second arm; a first electrode (electrode A) of the first intensity modulator; a second electrode (electrode B) of the second intensity modulator; a first main Mach-Zehnder electrode (MZ CA electrode) provided along at least a part of a waveguide portion between an output part of the first intensity modulator and the combining part; a second main Mach-Zehnder electrode (MZ CB electrode) provided along at least a part of a waveguide portion between an output part of the second intensity modulator and the combining part, wherein the first intensity modulator is a first Mach-Zehnder waveguide including the first electrode (electrode A), and the second intensity modulator is a second Mach-Zehnder waveguide including the second electrode (electrode B), and a control part for adjusting modulation time of an RF A signal, an RF B signal, a modulation signal applied to the first main Mach-Zehnder electrode (MZ CA electrode), and a modulation signal applied to the second main Mach-Zehnder electrode (MZ CB electrode), wherein the RF A signal is a radio frequency signal applied to the optical signal, the optical signal propagating through two arms composing the first sub Mach-Zehnder waveguide (MZ A ), and wherein the RF B signal is a radio frequency signal applied to the optical signal, the optical signal propagating through two arms composing the second sub Mach-Zehnder waveguide (MZ B ).