Abstract

Optical amplifiers are central to the increased use of fiber optics for video distribution. Conventional cable systems use an amplitude modulation format requiring highly linear DFB lasers of 50 dB CNR and -60 dBc of nonlinear distortion. Such lasers are of limited power, yielding an 8-10 dB optical power budget. However, erbium doped fiber power amplifiers (pumped by powerful 1480 nm and 980 nm diode lasers) improve this budget to better than 45 dB. Hence the role of fiber can be extended from feeder plant overlays to fiber-to-the-curb distribution systems. In digital video distribution systems the required 20 dB CNR allows the use of in-line fiber amplifiers. The optical power budget for a 16-QAM, 100 subcarrier, 400 video channel system increases from 25 dB to over 100 dB, allowing fiber-to-the-curb distribution for thousands of subscribers.

© 1992 Optical Society of America