Patent ID: 8718487
Filing Date: 2014-05-06
Classification: H04B,H04L

Abstract:
1. An optical transmitter for converting an input data series which is an input electrical signal into an optical multi-level signal and for outputting the optical multi-level signal, comprising: a look-up table in which data for executing optical multi-level modulation is stored and from which first modulation data and second modulation data are output based on the input data series; a first D/A converter which converts the first modulation data by D/A conversion to generate a first multi-level signal; a second D/A converter which converts the second modulation data by D/A conversion to generate a second multi-level signal; a look-up table circuit configured to compensate stored data which is stored in the look-up table based on characteristics of the first D/A converter and the second D/A converter; and a dual-electrode MZ modulator which comprises a first phase modulator for modulating light from a light source in accordance with the first multi-level signal and a second phase modulator for modulating light from the light source in accordance with the second multi-level signal, and which combines an optical signal from the first phase modulator and an optical signal from the second phase modulator to output the optical multi-level signal, wherein the look-up table has an address size equal to or larger than a signal multiplicity of the optical multi-level signal and a bit width equal to or larger than a quantifying bit number of the first and second D/A converters.