MODULATION INDEX MEASUREMENT SYSTEM IN LIGHT DIRECT MODULATION PSK SYSTEM AND METHOD FOR CONTROLLING SEMICONDUCTOR LASER USING IT

摘要

PURPOSE: To enable a modulation index to be measured easily. ;CONSTITUTION: An intermediate frequency signal obtained by detecting what is obtained by superposing a signal light modulated by the PSK system with a local oscillation light is doubled by a frequency doubler 5 and is fed to a frequency analyzer 6, thus obtaining a modulation index based on a frequency difference of large two frequency components which appear at the frequency analyzer 6.;COPYRIGHT: (C)1993,JPO&Japio