The Future Symbiosis of Optical Fibre and Microwave Radio Systems

Many of the time-honoured techniques developed during the sixty-year history of microwaves are now being adopted for optical fibre applications. Until comparatively recently, optical systems were more akin to the early wireless spark transmitters rather than the now sophisticated and ubiquitous radio systems. However, with the advent of coherent optics and photonic amplifiers based on semiconductor laser structures and pumped non-linear undoped/doped fibre, the next generation of optical systems looks set to ape modern microwave radio. The use of optical heterodyne techniques and the arrival of intermodulation distortion are the first indication of a symbiotic relationship, with radio using thousands of electrons/bit in comparison with optics which requires <100 photons/bit. In this paper we explore the migration of optical system development and the future complementary role of microwave radio.