OPTICAL SIGNAL SYNCHRONIZATION SAMPLING DEVICE, ITS METHOD, OPTICAL SIGNAL MONITOR DEVICE USED THEREFORE, AND ITS METHOD

摘要

An electroabsorption optical modulator used as an element for sampling comprises two optical terminals for inputting/outputting a light beam and a power supply terminal for imparting an electric field to an optical path connecting the two optical terminals and has a characteristic that the absorptivity to the light propagating through the optical path varies with the magnitude of the magnetic field. The optical signal which is the object of monitoring (synchronous sampling) is made to enter one of the two optical terminals. A predetermined DC voltage exhibiting a high absorptivity to the optical signal is applied to the power supply terminal. A sampling optical pulse is made to enter the other optical terminal through an optical coupler. Because of the mutual absorption saturation characteristic of the electroabsorption optical modulator caused when the sampling optical pulse enters the other terminal, the absorptivity to the optical signal is decreased, and thus the optical signal undergoes synchronous sampling. As a result, the optical signal is made to exit from the other optical terminal through the optical coupler.