Abstract

Efficient signal transmission at millimeter wave frequencies is essential for applications such as phased array radars, antenna remoting, and low-loss delay lines. Optical fibers with their light weight, low loss, and immunity to electromagnetic interference are an excellent medium for signal transmission at these frequencies. Millimeter wave modulated light may be generated by direct modulation, use of an external modulator, optical heterodyning, or resonantly enhanced external cavity lasers. Direct modulation bandwidth of semiconductor lasers is presently limited to 30 GHz.¹ Resonant enhancement of the modulation response greatly increases the transmission efficiency^2,3 at frequencies beyond this. In this scheme, optical feedback from the mirror in the external cavity causes the modulation response to be enhanced at frequencies corresponding to multiples of the cavity round trip time up into the millimeter wave range.

© 1993 Optical Society of America