To provide a multivalued optical pulse train analyzer/controller which automatically analyzes and controls the intensity of a high-speed high-power multivalued optical pulse train.

The multivalued optical pulse train analyzer/controller is provided with an optical pulse generator 103 which provides at least low-, intermediate-, and high-level optical intensities by generating the high-speed high-power multivalued optical pulse train, a photodetector 105 which is optically coupled with the generator 103 and generates an electric pulse train having an amplitude level including low-, intermediate, and high-amplitude levels in accordance with the optical intensity level of the optical pulse train, and at least one reference 107. The analyzer/controller is also provided with an analyzer 109 which is electrically coupled with the reference 107 and photodetector 105 and analyzes the amplitude level of the electric pulse train by comparing the level with the reference 107 and a controller 111 which is electrically coupled with the analyzer 109 and generates a high-level correct signal based on the analyzed results of the high-amplitude level.