Digital optical transmission apparatus and method for performing ASK modulation to generate base band component with constant DC level

摘要

A digital optical transmission apparatus includes a modulation portion for modulating data to be transmitted in an ASK modulation method, and an E/O modulation portion for converting an electrical signal output from the modulation portion into an optical signal having a base band component with a constant DC level. DC-biased or FSK-biased may be employed as a method of making constant the DC level of the base band component.