Patent ID: 9191121
Filing Date: 2015-11-17
Classification: H04B

Abstract:
1. An optical transmitter comprising: an optical modulator comprising a first modulator and a second modulator connected in parallel to each other in the form of a Mach-Zehnder interferometer, and a phase shifter connected to the second modulator in series; a signal generator configured to generate a single carrier signal or multi-carrier signals and apply the generated single carrier signal or multi-carrier signals to the optical modulator; and an output stabilizer configured to stabilize a final output optical signal of the optical modulator by controlling a bias applied to each of the first modulator, the second modulator and the phase shifter, wherein the output stabilizer comprises: an optical signal characteristic detector configured to convert an optical signal output from the optical modulator into an electrical signal; and an optical modulation controller configured to apply first and second bias dithering signals, each having a same frequency, to the first modulator and the second modulator, respectively, check voltages of the first and second bias dithering signals from the converted electrical signal, and control each of the biases applied to the first and second modulators such that each of the voltages is minimized.