Patent ID: 7245413
Filing Date: 2007-07-17
Classification: G02F

Abstract:
1. A light modulation apparatus including a Mach-Zehnder type light modulator performing modulation of a light entered from a light source to output the modulated light as an output light signal, a driver for modulator outputting a control signal for controlling an operation related to the modulation according to an input electric signal input from an outside to the light modulator, a light branching circuit branching the output light signal output from the light modulator, and a bias control circuit applying a bias voltage to the light modulator based on the branched output light signal, the apparatus further comprising: a burst pause state detection circuit detecting a pause state of a burst signal included in the input electric signal; a photoelectric transducer converting an output light signal branched by the light branching circuit into an electric signal; a sampling circuit extracting the electric signal converted by the photoelectric transducer while the pause state is detected by the burst pause state; and a bias voltage adjustment circuit adjusting a bias voltage value of the bias voltage based on a voltage level of the extracted electric signal.