Henry A. Blauvelt

An experimental and theoretical study of the suppression of interferometric noise and distortion in AM optical links by phase dither

The effects of phase dither on the magnitude and spectral distribution of interferometric fiber optic noise and intermodulation products is considered. A theory is presented as well as experimental data which show major reduction of AM noise brought about by intentional narrow band and wide band phase dither of the laser output.

Optimum range for DFB laser chirp for fiber-optic AM video transmission

Simple expressions for the impact of the distributed feedback (DFB) laser chirp on the system noise and distortion specifications of AM CATV fiber links are derived. These expressions are found to agree well with measured results. There is a narrow range of chirp for which the degradation of both noise and distortion is low. 1310-nm lasers are found to have chirp within the acceptable range. 1550-nm lasers are found to have chirp that is unacceptably large for most CATV applications.

Microwave fiber optic link with DFB lasers

The current status of microwave fiber optic links is discussed. It is noted that to date, high-speed links are limited not only by the available bandwidth of analog lasers but also by the fiber dispersion effect on link parameters. New 15 GHz distributed feedback lasers are capable of significantly reducing dispersion problems while providing enhanced bandwidth. An optical isolator with the microwave circuitry makes it possible to reach coupling efficiencies as high as 60 percent.