High-performance fiber-optic links for microwave applications

Directly and externally modulated fiber-optic links are examined using a number of parameters of importance in microwave applications. The parameters considered are gain and frequency response, noise figure, intermodulation-free dynamic range, cancellation ratio, and AM/FM noise. It is noted that considerable progress has been made over the last few years in fiber-optic links using both direct and external modulation. The improvements in directly modulated links stem mainly from the introduction of distributed-feedback diode lasers. Externally modulated links have benefited primarily from an improved understanding of the scaling of link gain and noise figure with average optical power.<>