The Role of A Linearized External Modulator in The Video Distribution Network

The past two years has seen the introduction of high quality linear fiberoptic transmitter into the CATV trunk plant. These lasers to date have been limited to 1.3 um. With the rapid maturity of optical fiber amplifiers (EDFA) which operates at 1.5 urn window, linear source operation at 1.5 urn are becoming increasingly important. This presentation will focus primarily on the use of external modulator as a 1.5 urn signal source. The key parameters influencing the signal source selection will be outlined. Linearization techniques of intensity external modulators will be reviewed. Then, results of an electronic predistortion linearization approach are detailed. The attractive features of using this type of signal source in a video multicast system employing EDFA are also described.